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ENGINEERING (1290 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 8)
3D Research     Hybrid Journal   (Followers: 20)
AAPG Bulletin     Hybrid Journal   (Followers: 8)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 5)
ACS Nano     Hybrid Journal   (Followers: 299)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 7)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 3)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 10)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 9)
Advanced Journal of Graduate Research     Open Access  
Advanced Nonlinear Studies     Hybrid Journal  
Advanced Science     Open Access   (Followers: 6)
Advanced Science Focus     Free   (Followers: 5)
Advanced Science Letters     Full-text available via subscription   (Followers: 11)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 4)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 28)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 14)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 23)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 29)
Advances in Nonlinear Analysis     Hybrid Journal  
Advances in Operations Research     Open Access   (Followers: 12)
Advances in OptoElectronics     Open Access   (Followers: 6)
Advances in Physics Theories and Applications     Open Access   (Followers: 16)
Advances in Polymer Science     Hybrid Journal   (Followers: 45)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 49)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 3)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 6)
AIChE Journal     Hybrid Journal   (Followers: 35)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access   (Followers: 1)
Al-Nahrain Journal for Engineering Sciences     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 27)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 10)
American Journal of Engineering Education     Open Access   (Followers: 11)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 25)
Annals of Combinatorics     Hybrid Journal   (Followers: 4)
Annals of Pure and Applied Logic     Open Access   (Followers: 3)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Antarctic Science     Hybrid Journal   (Followers: 1)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 20)
Applied Clay Science     Hybrid Journal   (Followers: 6)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 13)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access   (Followers: 3)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 6)
Applied Sciences     Open Access   (Followers: 3)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Arab Journal of Basic and Applied Sciences     Open Access  
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 9)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asia-Pacific Journal of Science and Technology     Open Access  
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 9)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Automotive Experiences     Open Access  
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 5)
Batteries     Open Access   (Followers: 6)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 28)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 1)
BER : Motor Trade Survey     Full-text available via subscription  
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 1)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Beyond : Undergraduate Research Journal     Open Access  
Bhakti Persada : Jurnal Aplikasi IPTEKS     Open Access  
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Bilge International Journal of Science and Technology Research     Open Access  
Biofuels Engineering     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 11)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering     Hybrid Journal   (Followers: 1)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 20)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 35)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomicrofluidics     Open Access   (Followers: 5)
BioNanoMaterials     Open Access   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 41)
Bitlis Eren University Journal of Science and Technology     Open Access  
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 12)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 13)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 14)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers Droit, Sciences & Technologies     Open Access  
Calphad     Hybrid Journal   (Followers: 2)
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 31)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 43)
Carbon Resources Conversion     Open Access   (Followers: 1)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 6)
Case Studies in Thermal Engineering     Open Access   (Followers: 6)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 7)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal  
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 3)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencia y Tecnología     Open Access  
Ciencias Holguin     Open Access   (Followers: 3)
CienciaUAT     Open Access   (Followers: 1)
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 13)
City, Culture and Society     Hybrid Journal   (Followers: 22)
Clean Air Journal     Full-text available via subscription   (Followers: 1)
Clinical Science     Hybrid Journal   (Followers: 9)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 6)
Coatings     Open Access   (Followers: 4)
Cogent Engineering     Open Access   (Followers: 3)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 3)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 15)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Information Science and Management Engineering     Open Access   (Followers: 4)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 28)
Composite Interfaces     Hybrid Journal   (Followers: 7)
Composite Structures     Hybrid Journal   (Followers: 291)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 225)
Composites Part B : Engineering     Hybrid Journal   (Followers: 262)
Composites Science and Technology     Hybrid Journal   (Followers: 200)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access   (Followers: 1)
Computational Geosciences     Hybrid Journal   (Followers: 17)
Computational Optimization and Applications     Hybrid Journal   (Followers: 8)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Science and Engineering     Open Access   (Followers: 19)
Computers & Geosciences     Hybrid Journal   (Followers: 31)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 9)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 5)

        1 2 3 4 5 6 7 | Last

Journal Cover
Case Studies in Thermal Engineering
Journal Prestige (SJR): 0.991
Citation Impact (citeScore): 3
Number of Followers: 6  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2214-157X
Published by Elsevier Homepage  [3162 journals]
  • Parametric analysis on the temperature response rules in inner surfaces
           for the homogeneity walls

    • Abstract: Publication date: Available online 13 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Xi Meng, Wentao Hu, Jiao Zhou, Ying Cao, Yanna Gao, Lili Zhang The response rules of the surface temperature with indoor air temperature have been particularly important under the air-conditioning and heating intermittent operation due to their affecting the thermal comfortable level and building energy consumption. In this study, a homogeneity wall was built and the effect of many parameters including the density, the specific heat capacity, the heat conductivity coefficient, the convective heat transfer coefficient, initial temperature and setting temperature of indoor air was analyzed on the response rules of surface temperatures by the analytical solution of the one-dimensional and unsteady heat conduction equation. And a multi-factor coupling regression formula was obtained for the time constant, which was used to evaluate the response rate of inner surface temperature.
  • Cattaneo-Christov model for Electrical Magnetite Micropoler Casson
           Ferrofluid over a stretching/shrinking sheet using effective thermal
           conductivity model

    • Abstract: Publication date: Available online 12 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Zahir Shah, Abdullah Dawar, I. Khan, Saeed Islam, Dennis Ling Chaun Ching, Aurang Zeb Khan Nanofluids are the key building block of nanoparticles. So in particular, the researchers got attention in the development of nanotechnology. The knowledge of heat transmission in magnetohydrodynamic nanofluid flows through diverse geometries is significant for heat exchangers design, transpiration, fiber coating, etc. Currently, the nanomaterial's are among the well-known tackles for refining the low thermal conductivity of working liquids. Naturally, magnetite (Fe3O4) nanoparticles move randomly within the base fluid. When transverse magnetic force is applied, the motion of nanofluid becomes uniform. With this instigation, a mathematical model is developed to examine the heat transmission performance of electrically conducting MHD flow of a Casson ferrofluid over a stretching sheet. Moreover, we have considered water as a base fluid in this work. The formulated model has been solved with homotopy analysis method (HAM) by using similarity variables. The impact of embedded parameters on velocity, micro-rotation velocity, and temperature profiles have been shown graphically and discussed in detail. Also the impact of embedded parameters on surface drag force and heat transfer rate have been shown through tables and discussed as well.
  • Cooling performance of Al2O3-water nanofluid flow in a minichannel with
           thermal buoyancy and wall conduction effects

    • Abstract: Publication date: Available online 12 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): C.J. Ho, Yu-Hui Chiou, Wei-Mon Yan, Mohammad Ghalambaz The effect of highly conductive thick walls on the mini channel heat transfer performance is systematically addressed while two constant heat flux sources are considered at the bottom of the channel. The influence of using different mass fractions of Al2O3 nanoparticles dispersed in water as working fluid are studied. The buoyancy effects on the thermal performance and pressure drop of the mini channel are also investigated. The finite volume method is employed to simulate the flow and heat transfer of nanofluid in the channel. The results show that the axial heat transfer is an important effect in mini channels with thermal conductive walls and should be taken into account. It is found that the presence of nanoparticles with the mass fraction of 5% and 10% drops the maximum temperature (and increases the pressure drop) by 1.28% (17.0%) and 1.48% (41.0%), respectively when Reynolds number is 500 and neglecting buoyancy effects. The presence of buoyancy effects reduces the pressure drop by 21.08% in a case with Reynolds number 500 and the nanoparticles mass fraction 5%. This is while the presence of buoyancy effects would decrease the maximum temperature by 1◦C.
  • Room air conditioning performance using liquid-suction heat exchanger
           retrofitted with R290

    • Abstract: Publication date: Available online 6 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): D.M. Nasution, M. Idris, N.A. Pambudi In this paper, a study of room air conditioning performance when using a liquid-suction heat exchanger retrofitted with R290 has been carried out with the aim of determining the influence of LSHX and R290 in terms of refrigeration effect, power consumption, COP, and heat exchanger effectiveness. A liquid-suction heat exchanger (LSHX) with length of 178 mm was designed and installed in air conditioning pipelines. The RAC used is a split-type with input power of 395 W and initial refrigerant R22. The experiment was conducted on two system conditions with 6 tests each. The results showed that LSHX provides an advantage in improving the energy efficiency of the standard RAC systems. Energy savings and increased COP can be as much as 27.69% and 38.29%. The adoption of R290 also helps reduce the potential of ozone depletion and global warming. It can be concluded that the combination of LSHX and R290 can produce better performance.
  • Case study for co and counter swirling domestic burners

    • Abstract: Publication date: March 2018Source: Case Studies in Thermal Engineering, Volume 11Author(s): Ashraf Kotb, Hany Saad In this case study, the influence of equivalence ratio for co and counter-swirl domestic burners compared with non-swirl design on the thermal efficiency as well as CO emissions has been studied using liquefied petroleum gas (LPG). Also, the flame stability, and pot height, which is defined as the burner-to-pot distance (H), of the co and counter domestic burners were compared. The analysis of the results showed that, for both swirl burners co and counter one the thermal efficiency under all operation conditions tested is higher than the non-swirled burner (base burner). For example, the thermal efficiency increased by 8.8%, and 5.8% than base burner for co and counter swirl, respectively at Reynolds number equal 2000 and equivalence ratio 1. The co and counter swirl burners show lower CO emission than the base burner. The co swirl burner has wider operation range than counter swirl. With the increase of pot height, the thermal efficiency of all burners decreases because the flame and combustion gases are cooled due to mixing with ambient air. As a result, the heat transfer is decreased due to atmospheric loss, which decrease the thermal efficiency.
  • Overall performance optimization of a spiral pipe type heater by fluid-
           structure interaction modeling and partitioning screening method

    • Abstract: Publication date: March 2018Source: Case Studies in Thermal Engineering, Volume 11Author(s): Lei Guo, Guofeng Li, Yu Liu, Ganqing Zhang, Zechao Wu A spiral pipe type heater is applied to the natural gas transportation system to inhibit gas hydrate, but fracture failure often happens at the joint of a coil pipe and a gathering pipe. To understand the mechanical behavior of the spiral pipe heater, a mechanical model of the coil pipe acted by the gas fluid is constructed, and the mechanical characteristics of the fracture point are obtained by numerical calculation. Then, the relation between angle parameters and the axial force, shear force, bending moment as well as stress of the structure is gotten. Comparison calculations of heat exchange before and after structural adjustment are done to get the optimized structure parameters of better mechanical properties and high heating rate. From this study, it is found that although the mechanical properties are improved, when increasing an angle parameter, the heat transfer performance is decreased. A coordination method is used for resolving the contradiction between heat transfer performance and mechanical properties to get an overall performance optimization. The provided partitioning screening method can improve the heating efficiency and mechanical properties of the heater obviously and conveniently.
  • New design of solar chimney (case study)

    • Abstract: Publication date: March 2018Source: Case Studies in Thermal Engineering, Volume 11Author(s): Omer Khalil Ahmed, Abdullah Sabah Hussein The solar chimney power plant has a promising future in the world. Α new design of solar chimney is offered including both PV panels with solar chimney plant for electricity generation. Two experimental models of a hybrid solar chimney were built and designed (systems A&B). System (A) had a collector glass roof cover and a PV panel as an absorber with a chimney of 2 m height while system (B) is similar to system (A) but with PV panel as collector roof cover and plywood as an absorber in the base of the chimney.Two similar experimental models were built to achieve the performance of these new designs. Practical tests were conducted in Kirkuk (35° 28' latitude and 44° 24' longitude), northern Iraq. The results showed that system (A) had higher thermal gain than system B while the daily average of electrical power in system (B) was (75.6 W) higher than system (A) (79 W). This is because the high thermal gain raised the operating temperature of the PV panel which led to a decrease in its power output. The results also presented that system (A) converted thermal power to kinetic power with daily average (0.008 W) because of the great thermal gain which made air less dense in turn increased its velocity more than system (B) (0.006 W) which had lower kinetic power. The total useful power produced by the system (B) is greater than the useful power produced from the system (A).
  • Reduction of the return temperature in district heating systems with an
           ammonia-water absorption heat pump

    • Abstract: Publication date: Available online 30 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): N. Mirl, F. Schmid, K. Spindler In this study, a new setup for the reduction of the return temperature in district heating systems will be presented. For this purpose, an ammonia-water absorption heat pump will be integrated within a district heating substation and theoretically investigated. The idea of this coupling is that the district heating flow is used to power the generator of the heat pump. The district heating return is cooled in the evaporator. In this way, the capacity of the district heating system can be increased or the mass flow rate can be reduced. Additionally, the lower return temperature leads to a higher efficiency of the whole system.The field of possible operating points for such a system will also be revealed and discussed.
  • Darcy-Forchheimer Flow of Radiative Carbon Nanotubes with Microstructure
           and Inertial Characteristics in the Rotating Frame

    • Abstract: Publication date: Available online 30 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Zahir Shah, Abdullah Dawar, Saeed Islam, Ilyas Khan, Dennis Ling Chuan Ching The current study deals with Darcy-Forchheimer three-dimensional micropolar rotational nanofluid flow of single wall and multiwall carbon nanotubes base on the fluids (water, engine oil, ethylene glycol and kerosene oil). The nanofluid flow are examined between parallel and horizontal plates in a rotating system. The micropolar nanofluid in permeable media is designated by assuming the Darcy-Forchheimer model where drenching permeable space obeys the Darcy-Forchheimer expression. The thermal radiation impact is taken to be varying in the absorption/generation for the purpose, to see the concentration as well as the temperature modifications between the nanofluid and the surfaces. The impacts of the porosity, rotation and inertia coefficient analysis have been mainly focused in this research. Plots have been presented in order to examine how the velocities and temperature profile get affected by various flow parameters. The leading equations are converted to a system of differential nonlinear equations and then homotopic method has been used for solution.
  • Research on temperature profile in a large scaled floating roof oil tank

    • Abstract: Publication date: Available online 27 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Lin Yang, Jian Zhao, Hang Dong, Junyang Liu, Weiqiang Zhao The temperature test system for the floating roof oil tank is established. Four different kinds of test tubes are invented to test the temperature profile in the oil tank. Based on the test system, the temperature profile of a 10×104 double-deck floating roof oil tank is investigated. There are three low temperature regions near walls in the tank, surrounded by these regions is the high temperature region in the center of the tank. The temperature distribution in different regions is presented in detailed. With the changing of ambient temperature, there is the corresponding temperature fluctuation of oil in the surface layer. With the ambient temperature increasing, the influence range decreases. And as the variation of ambient temperature increases, the temperature fluctuation of oil increases. Moreover, the heating process of oil in the tank by the entering oil is presented by the test data. Based on the principle of conservation of energy, the total heat transfer coefficient of oil tank on different working conditions is calculated with the value from 1.09 W/m2 °C~2.32 W/m2 °C.
  • Analysis of Activation Energy in Magnetohydrodynamic Flow with Chemical
           Reaction and Second Order Momentum Slip Model

    • Abstract: Publication date: Available online 26 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Aaqib Majeed, F.M. Noori, A. Zeeshan, T. Mehmood, S U Rehmand, I. Khan This paper is communicated theoretically to study the collective effects of Arrhenius activation energy and binary chemically reactive species in the presence of the second order momentum slip model which has not been studied so far. To support these declaration in addition with electrically conducting boundary layer flow and heat transport have considered towards an exponential stretching sheet. The current study incorporates the impact of activation energy, temperature difference ratio parameter, 1st and 2nd order slip parameter, chemical reaction rate on fluid velocity, fluid temperature and concentration of chemical species are elaborated through graphically and discussed in detail. Appropriate transformations are betrothed to acquire nonlinear highly coupled ordinary differential equations (ODE's) from partial differential equations which are then solved numerically by employing finite difference collocation process that apply three-stage Lobatto IIIa scheme. The obtained results confirm that an excellent agreement is achieved with those available in open literature. It is found that concentration profile decreases in the presence of chemical reaction rate and temperature difference ratio parameter whereas opposite demeanour is seen for activation energy.
  • Thermal Performance Analysis of Net Zero Energy Home for Sub Zero
           Temperature Areas

    • Abstract: Publication date: Available online 25 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Muhammad Irfan, Naeem Abas, Muhammad Shoaib Saleem With the increase in energy demand globally, environmental risks are also becoming more serious than ever before. Emission of carbon dioxide (CO2) and other greenhouse gases (GHGs) are hastily contributing to global warming and ozone depletion phenomenon. Buildings play a major role in consumption of energy and emission of greenhouse gases. It is need of the hour to design such buildings which have zero emission and have renewable resources of energy for on-site generation. The theory of net zero energy and zero emission home is hot topic in the sustainable building industry these days. This study targets to design a model towards energy-neutral or net-zero energy home in sub-zero temperature areas. On-site renewable energy resources are employed to generate energy independently including solar and wind energy. System is simulated for whole year on hourly basis in TRNSYS® simulation software. Results have shown good tendency for the construction of net-zero energy homes and renewable energy resources have shown promising outputs for on-site energy generation. Cold climate areas may have lower energy generation due to lower solar insolation during winter season. Pakistan has shown very good results and surplus energy produced. Lowest value of photovoltaic electric power generated is recorded 680 W in Barcelona during January, whereas Sydney has a lot of potential for PV generation of 1400 W. For wind turbine with hub height at 46 m, system produced 0.2 MW lowest value in California and highest value 1.85 MW in Karachi. Annual peak zone temperature has been recorded for Lahore 65 °C. System designed finds highest implementation with stated conditions.
  • Entropy generation in MHD radiative viscous nanofluid flow over a porous
           wedge using the bivariate spectral quasi-linearization method

    • Abstract: Publication date: Available online 23 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): S.P. Goqo, S.D. Oloniiju, H. Mondal, P. Sibanda, S.S. Motsa We study the viscous nanofluid flow over a non-isothermal wedge with thermal radiation. The entropy due to irreversible processes in the system may degrade the performance of the thermodynamic system. Studying entropy generation in the flow over a porous wedge gives insights into how the system is affected by irreversible processes, and indicate which thermo–physical parameters contribute most to entropy generation in the system. The bivariate spectral quasi-linearization method is used to find the convergent solutions of the model equations. The impact of significant parameters such as the Hartmann number, thermophoreis and Brownian motion parameter on the fluid properties is evaluated and discussed. The Nusselt number, skin friction coefficients and Sherwood number are determined. An analysis of the rate of entropy generation in the flow for various parameters is presented, and among other results, we found that the Reynolds number and thermal radiation contribute significantly to entropy generation.
  • Theoretical Analysis of Humidification – Dehumidification Process in an
           Open Type Solar Desalination System

    • Abstract: Publication date: Available online 23 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Salman H. Hammadi A theoretical study of humidification – dehumidification (HDH) process in transient mode inside an open solar distiller is presented. Energy and mass balances of the water layer, airstream, and glass cover of the distiller are formulated and numerically simulated. Dry air enters into the distiller is heated up and humidified by solar radiation. When the glass temperature is lower than or equal to the dew point of the humid air, the vapor condenses on the inner side of the glass cover and runs down where the fresh water is collected. The results show that the productivity of fresh water is strongly affected by the water, air, and glass temperatures and the maximum productivity achieved in March was 2.2 kg/ The increase in air velocity inside the solar distiller increases the evaporation rates and decreases the productivity. The distiller length required to reach the saturated state essentially depends on the air velocity and the water temperature. A comparison of the current analysis with other works showed a good agreement.
  • Absorption refrigeration system using engine exhaust gas as an energy

    • Abstract: Publication date: Available online 22 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Sorawit Kaewpradub, Prawit Sanguanduean, Wattanapong Katesuwan, Nares Chimres, Phatthi Punyasukhananda, Lazarus Godson Asirvatham, Omid Mahian, Ahmet Selim Dalkilic, Somchai Wongwises A single-effect absorption refrigeration system that uses LiBr-water solution and engine exhaust gas is investigated. The generator is a spiral fin-and-tube heat exchanger, while the condenser, evaporator, and absorber are shell and coil heat exchangers. Experiments are conducted at engine speeds of 1000, 1200, 1400, and 1600 RPM; expansion valve opening percentages of 54.5%, 72.7%, and 90.9% at the separator outlet and 3.41%, 4.55%, and 5.68% at the condenser outlet; refrigerant temperatures at the condenser outlet of 25, 30, and 35 °C; and LiBr-water solution flow rates of 0.35 and 0.7 LPM. The results show that the system could work with an engine speed of 1200 to 1400 RPM. The cooling load and coefficient of performance (COP) increase with increasing engine speed. The highest COP of 0.275 is reached at an engine speed of 1400 RPM, opening percentage of 72.7% at the separator outlet and 4.55% at the condenser outlet, water temperature of 25 °C at the condenser outlet, and LiBr-water flow rate of 0.7 LPM. The decreased refrigerant temperature at the condenser outlet helps to increase both cooling load and COP. The increase of the LiBr-water solution flow rate helps to increase cooling load but decrease COP.
  • Effect of Diffuse Solar Radiation on the Thermal Performance of Solar

    • Abstract: Publication date: Available online 21 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Kung-Ming Chung, Chia-Chun Chen, Keh-Chin Chang To characterize the thermal performance of solar thermal collectors, lab tests are required to evaluate the maximum thermal efficiency and heat loss. The CNS 15165-1:2008 is in compliance with ISO 9806:1994, which is an outdoor steady-state test method. The test time may get quite long due to the requirement of the ratio of diffuse to global solar radiation. The experimental data indicate the effect of diffuse solar radiation on the thermal performance of glazed, metallic, flat-plate solar thermal solar collectors is not significant.
  • Numerical analysis of flow and heat transfer enhancement in a horizontal
           pipe with P-TT and V-Cut twisted tape

    • Abstract: Publication date: Available online 13 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Azher M. Abed, Hasan Sh. Majdi, Zainab Hussein, Doaa Fadhil, Ammar Abdulkadhim In this work, forced convection heat transfer through a horizontal pipe built-in with/without twisted tape-inserts is numerically studied under a uniform heat flux condition. Water is used as a working fluid. The governing equations are numerically solved in the domain by a finite volume method (FVM) using the Realizable κ–ε (RKE) model. The computational results are performed for a range of the Reynolds number (4000 ≤ Re ≤ 9000), the twisted ratio (4.0 ≤ TR ≤ 6.0), and heat flux (5000 ≤ q ≤ 1000 W/m²). Two type of twisted tape which inserts across a circular pipe (P-TT) and (V-cut) are carried out. The influence of these parameters on the local, average Nusselt Number and the thermal performances were examined and compared with a plain pipe under similar conditions. The results show that the average Nusselt number and friction factor raise as the twisted ratio rise for any value of Reynolds number. Furthermore, thermal performance factor tended to increase with increasing Re and decreasing tape twist ratio. Obviously, the (V-cut) twisted- tape and (P-TT) twisted tape with TR = 4 gave a higher mean thermal performance factor (4.45, and 4.19) than that with TR = 6, respectively. Finally, the present study can offer some useful results to select optimum geometrical parameters for use in shell and tube heat exchangers with a twisted tape inserted based on their specific applications.
  • Study of Heat Transfer with Surface Treatment in Pre-Coolers for
           Aeroengine Applications

    • Abstract: Publication date: Available online 10 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Rangesh Jagannathan, Mark Elliott, Craig Johansen, Simon Park The effect of surface roughness on convective heat transfer and pressure drop is assessed for a simplified pre-cooler system for application in high-speed airbreathing engines. The pre-cooler system comprises of four circular cylinders in cross-flow inside a square duct. The cylindrical wires of 1 mm diameter were textured using an economical method of surface treatment, via sand-blasting with 100 μm (diameter) particles. Experiments were conducted at Reynolds numbers ranging from 600 to 8000. The Nusselt number was observed to decrease for the rough wires, indicating decreased convective heat transfer rates. Moreover, roughness was found to have no appreciable effect on pressure drop for these conditions. This is attributed to a fully developed turbulent duct flow upstream of the wires, which was confirmed by observing the Nusselt-Reynolds number correlation for treated and untreated cases. Surface roughness strategy in pre-coolers for an ascent trajectory of a high-speed airbreathing engine is also discussed.
  • Cycle improvement and hydrogen steam superheating at Mutnovsky geothermal
           power plant

    • Abstract: Publication date: Available online 9 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Dunikov This study is aimed at a possibility of hydrogen production and hydrogen steam superheating at a single-flash 50 MW Mutnovsky geothermal power plant stage 1. A modification by introduction of a low-pressure single-flash unit utilizing energy of the separated liquid is proposed, and the integrated single- and double-flash cycle is analyzed. The second flash process gives a maximum possible increase of the installed capacity on 11.1 MW for the flash temperature of 92 °C, and 9 MW for 120 °C. Currently the plant does not use 12.3% of the geothermal steam for electricity generation, partly due to demand side management from a grid operator. Excess power can be used for water electrolysis and for each 1% of saved steam 92 t of H2 can be produced annually. Hydrogen combustion in a high temperature hydrogen-oxygen steam generator can be used for steam superheating in a second flash process, achieving the increase of steam temperature at the low pressure turbine inlet by 20–30 K, and an increase of steam dryness at the turbine outlet by 2–4%. Additional available power rises by 5–10% (0.5–0.9 MW) and overall thermal efficiency of the plant can be increased from 10% to 12.5%.
  • Influence of the base fluid on the thermo-physical properties of PV/T
           nanofluids with surfactant

    • Abstract: Publication date: Available online 9 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Ali H A Al-Waeli, Miqdam T Chaichan, K Sopian, Hussein A Kazem Nanofluids have become widely used in different applications. One of these applications, it may be used in Photovoltaic/Thermal PV/T systems, as there is many research that works to determine the best type of nanofluids for this important application. In this study, differences in the thermo-physical properties of three types of nanofluids were emphasized, which used nano-SiC as additive and cetyl-trichromyl ammonium bromide as surfactant. Water was mixed with 35% ethylene glycol, and with 35% of propylene glycol. The study aims to find the best base fluid for use in solar PV/T applications.The increase in density and viscosity of all studied nanofluids was evident as well as the superiority of the density of ethylene glycol water mixture (for the tested temperature range, nano-EG-water density was higher than nano-water and nano-PG-water densities by 15.51% and 0.066%, respectively compared to water). The propylene glycol-water mixture has higher viscosity than the other two nanofluids (it was higher than nano-water and nano-EG-water viscosities by 16.066% and 0.212%, respectively compared to water). The thermal conductivity of the three nanofluids was close to each other in the studied temperatures region. Glycol solutions were more stable than water when ultra-shaking hours were from four to six hours.
  • Influence of the oblique fin arrangement on the fluid flow and thermal
           performance of liquid cold plate

    • Abstract: Publication date: Available online 1 October 2018Source: Case Studies in Thermal EngineeringAuthor(s): Nur Irmawati Om, Rozli Zulkifli, P. Gunnasegaran Electric vehicle (EV) is advancing as the transportation industry and the demand is expanding globally. The use of liquid cold plate (LCP) in EV battery is more effective in providing the desire temperature rather than using the conventional air cooling. The use of straight fins is being switched to oblique-shape fins to assist disruption of the thermal boundary layer development. The arrangement of fins in the LCP also will affect the performance of it cooling the battery. Three different arrangement of the oblique fin are developed to enhance the fluid flow and heat transfer performance. The LCP contains three arrangements of oblique fin namely as inline, incline and loureved. Experimental and numerical results reveal the good aggrement where the Nusselt number is enhanced with the louvered arrangement. Among three arrangements, loureved obtained the lowest surface temperature of the battery followed by inline and incline. It also found that Nusselt number increases as the Reynolds number increases. The LCP is able to maintain the average surface temperature of the battery below permitted working temperature of 50°C. This shows that the present LCP with oblique fin could be a promising method for EV battery thermal management.
  • Average View Factors for Extended Surfaces with Fractal Perforations

    • Abstract: Publication date: Available online 25 September 2018Source: Case Studies in Thermal EngineeringAuthor(s): David Calamas, Daniel Dannelley Extended surfaces are often used for passive thermal management of electronic devices. By perforating extended surfaces in accordance with the Sierpinski carpet fractal pattern, an increase in surface area and a decrease in mass can be achieved. Intersurface thermal radiation, within the perforations, can account for a significant percentage of the total radiative heat transfer rate. As the perforations are of a non-uniform size, a correlation for the average fin view factor as a function of fractal iteration and width-to-thickness ratio was developed. For example, while a fin inspired by the fourth iteration of the Sierpinski carpet fractal pattern has 23.30% more surface area than a solid rectangular fin of equal width-to-thickness ratio the same fin only exchanges 67.37% of the radiation emitted with the surroundings due to intersurface thermal radiation. Regardless of width-to-thickness ratio, there was found to be a finite number of fractal iterations after which the average view factor of the extended surface approached zero. Similarly, the percentage of the total surface area that the perforations account for approaches an asymptote at approximately 100% by 10 iterations, regardless of width-to-thickness ratio. Finally, while there is an exponential increase in surface area with iteration, the increase in area did not offset the decrease in average view factor.
  • Optimization of Area Ratio and Thrust in Suddenly Expanded Flow at
           Supersonic Mach Numbers

    • Abstract: Publication date: Available online 24 September 2018Source: Case Studies in Thermal EngineeringAuthor(s): Khizar Ahmed Pathan, P.S. Dabeer, Sher Afghan Khan In this investigation the flow field has been computed by the numerical approach using Computational Fluid Dynamics (CFD) Analysis to investigate the efficacy of the supersonic Mach numbers due to the flow from supersonic nozzle exhausted in a larger circular duct and the corresponding thrust force created due assess the flow development in the circular pipe, its measurement and the magnitude. For this study the nozzles were modeled using academic licensed ANSYS Workbench software. The nozzles were modeled for the Mach numbers 1.5, 2.0 and 2.5. The flow from the nozzles was numerically simulated for nozzle pressure ratios (NPRs) in the range from 2 to 8, and the area ratios of the study were 2, 4, 6, 8 and 10. The simulation results were compared for geometrical and the kinematical parameters. The results indicate that the pressure in the base corner of enlarged duct is influenced by the level of expansion (i.e. Nozzle pressure ratio), inertia level (i.e. Mach number) at the nozzle exit and the relief available (i.e. area ratio) to the shear layer. If the maximum thrust is the aim then the optimum area ratios should be considered. Lower area ratio is not suitable for higher NPR and higher area ratio is not suitable for lower NPR. The higher area ratio provides more space to expand compressed air. Also, the lower area ratio will offer minimum base drag. The base drag is strongly influenced by the area ratio up to certain limit. If the area ratio is again increases then there is no effect of increase in the area ratio on the base drag and Thrust. As the Mach number increases for the same Nozzle pressure ratio and the area ratio, the net thrust force also increases. From the obtained results the optimum area ratio can be selected to maximize thrust for a given Nozzle pressure ratio and Mach number.
  • The Effect of Solar Radiation on the Energy Consumption of Refrigerated

    • Abstract: Publication date: Available online 20 September 2018Source: Case Studies in Thermal EngineeringAuthor(s): Muhammad Arif Budiyanto, Takeshi Shinoda Refrigerated containers are a special type of cargo container, equipped with an integral refrigeration unit. External power supply is required to run the refrigeration system to control the temperatures inside the container during transporting perishable goods. The amount of power consumption of Refrigerated container will change depending on many external variables. This paper provides an investigation of the effect of solar radiation on the energy consumption of Refrigerated container through experimentation. 40 ft high cube Refrigerated container is employed as a measurement object. Environmental parameters have been collected, i.e., solar radiation, surface temperature, and air temperature. Data analysis shows that the direct effect of solar radiation on the container surface causes the temperature penetration of the container wall and increases the amount of energy consumption. With the maximum solar radiation of about 700 W/m2 causes the surface temperature to reach up to 35 °C, and the maximum power consumption reaches 7.5 kW/h during the noon.
  • Extraction of Bio-Oil during Pyrolysis of Locally Sourced Palm Kernel
           Shells: Effect of Process Parameters

    • Abstract: Publication date: Available online 14 September 2018Source: Case Studies in Thermal EngineeringAuthor(s): J.O Ogunkanmi, D.M Kulla, N.O Omisanya, M. Sumaila, D.O Obada, D. Dodoo-Arhin The aim of this study was to determine the effect of particle size, pyrolysis temperature and residence time on the pyrolysis of locally sourced palm kernel shells and to characterize the bio-oil products. Pyrolysis experiments were performed at pyrolysis temperatures between 350 oC and 550 oC and particles sizes of 1.18 mm, 2.36 mm and 5 mm in a time range less than 120 mins. The maximum bio-oil yield was 38.67 wt.% at 450 oC for a feed particle size of 1.18 mm with a residence time of 95 mins. It was observed that the percentage of liquid collection was 28% of the total biomass feed for particle size of 1.18 mm. In terms of the effect of temperature, the lowest bio-oil yield was 28% of the total biomass feed at temperature of 550 oC. For the variation in residence time and the associated effects, the maximum liquid product was 38.67 wt.% of biomass feed, at a particle size of 1.18 mm for 95 mins. As observed, the optimum residence time was 95 mins as times either side led to a decrease in the liquid yield. The bio-oil products were analysed by Fourier Transform Infra-Red Spectroscopy (FTIR) and Gas Chromatography-Mass Spectrometry (GC-MS). The FTIR analysis showed that the bio-oil was dominated by phenol and its derivatives. The phenol (38.44%), 2-methoxy-phenol (17.34%) and 2, 6-dimethoxy phenol (8.65%) that were identified by GC-MS analyses are highly suitable for extraction from bio-oil as value-added chemicals. The highly oxygenated oils can therefore be upgraded in order to be used in other applications such as transportation fuels.

    • Abstract: Publication date: Available online 4 September 2018Source: Case Studies in Thermal EngineeringAuthor(s): P. Soto, L.A. Domínguez-Inzunza, W. Rivera A solar absorption cooling system of 5 kW of cooling capacity operating with the ammonia/lithium nitrate mixture was developed at the Instituto de Energías Renovables (IER) of the Universidad Nacional Autónoma de México (UNAM) and then transferred and installed at the Instituto Tecnológico de Culiacán (ITC), in Culiacán, Sin. The heat was supplied to the cooling system by means of a solar collector field. The cooled water produced by the absorption systems was used to provide air conditioning. Temperatures as low as 7 °C were achieved by the absorption system with COP varying from 0.28 to 0.48.
  • Case Study on Solar Water Heating for Flat Plate Collector

    • Abstract: Publication date: Available online 4 September 2018Source: Case Studies in Thermal EngineeringAuthor(s): Walaa Mousa Hashim, Ali Talib Shomran, Hasasn Ali Jurmut, Tayser Sumer Gaaz, Abdul Amir H. Kadhum, Ahmed A. Al-Amiery This paper describes performance solar water heating for flat plate collector. The system of thermal performance designed for dimensions 125 × 110 cm and width 25 cm, in such a way that fluid can flow from inlet to outlet through pipe with longer is 15.9 m, designed as lope square pattern, used the water as fluid flow working with two different flow rate (5.3 and 6.51 L/min). The experiments were carried out under the University of Technology, conditions of Baghdad, Iraq. The result shows that the water at flow rate 5.3 L/min heated more than the flow rate 6.51 L/min, which causes the higher efficiency and effectiveness of the collector, so the maximum temperature was (51.4 oC and 49 oC) at flow rate (5.3 L/min and 6.51 L/min) respectively. The main conclusion is that used this system to heated the water and then used in-house, building and other purposes.
  • Control of Electric Power Generation of Thermal Power Plant in TamilNadu

    • Abstract: Publication date: Available online 1 September 2018Source: Case Studies in Thermal EngineeringAuthor(s): M.S. Murshitha Shajahan, V. Aparna, D. Najumnissa Jamal, M.K.A. Ahamed Khan A control configuration for controlling the generated power in NLC TamilNadu Power Limited (NTPL) Thermal Power Station by manipulating the coal flow rate, air flow rate and feed water flow rate is proposed here. Real Time data from NTPL Thermal Power Station Unit-Tuticorin unit of 500 MW capacity is recorded over an interval of time. This real-time data is used to model the coal flow rate, air flow rate and feed water flow rate loops which will be controlled to eventually control the generated power. The controller for the three loops is tuned using evolution and optimization techniques like Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). Results of the controller tuned using both the techniques are provided and they are compared with each other. From the simulation results, it can be emphasized that the controller performs fairly well in servo and regulatory configurations.
  • Flow Characteristics of Two Dimensional Classical and Pulsating Jet in
           Crossflow at Low Reynolds Number

    • Abstract: Publication date: Available online 31 August 2018Source: Case Studies in Thermal EngineeringAuthor(s): Jianlong Chang, Xudong Shao, Jiangman Li Numerical cases are studied for the behaviors of two dimensional classical and pulsating jet in crossflow (JICF) with Reynolds number 100. The corresponding flow characteristics of two dimensional JICF are presented by k-ε model in this paper in the range of velocity ratio r 1≤r≤4.. Flow characteristics of vortex structure for two dimensional classical JICF have been analyzed first. The investigated vorticity field shows that the JICF falls into the turbulent flow with the increasing velocity ratio quickly. A vortex action is formed in the leeward side. The streamline field for the classical JICF have been obtained computationally and analyzed. The analysis of two dimensional pulsating JICF assumes the vorticity field at various velocity ratios, in which the ejected jet is enclosed by the fixed Strouhal number. The following analysis assumes the stream fields based on the same cases of the analyzed vorticity field. Vortex action area is also existing in the two dimensional pulsating JICF. Finally, the contrast of pulsating JICF with different Strouhal numbers have been obtained computationally and analyzed in detail to reveal the differences and connections between the pulsating JICF with different Strouhal numbers.
  • Drying behaviour of lemon balm leaves in an indirect double-pass packed
           bed forced convection solar dryer system

    • Abstract: Publication date: Available online 30 August 2018Source: Case Studies in Thermal EngineeringAuthor(s): Shahrbanou Shamekhi Amiri, Tahereh B. Gorji, Mofid Gorji-Bandpy, Mohammad Jahanshai The thin-layer drying behaviour of lemon balm leaves in an indirect-mode solar dryer with forced convection was investigated. The solar air heater employed a novel counter flow double-pass packed-bed wire mesh layer configuration to enhance the energy gain of the heated air. The thermal performance of the solar dryer was experimentally evaluated under Babol (36.5387 ° N, 52.6765°E) prevailing weather conditions. The system was comprised of a double-pass packed bed of wire mesh air heater attached to a dryer cabinet. The collector thermal efficiency was determined under realistic conditions wherein solar irradiance changed from 600 to 900 W/m2, atmospheric temperature varied from 22 °C to 25 °C and the collector outlet temperature ranged from 38 °C to 68 °C. It was found that while increasing the flow rate from 0.006125 m3/s to 0.01734 m3/s improved the collector thermal efficiency by ~ 20%; further increasing the flow rate to 0.034378 m3/s had an adverse effect on the collector efficiency. Drying experiments were performed for lemon balm leaves with initial moisture content of 80% on wet basis to the final moisture content of 10%. Mathematical models were also tested to find the best thin layer model for describing the drying behaviour of lemon balm leaves.Graphical abstractGraphical abstract for this article
  • Numerical investigation of heat transfer from multi‒bulges pins

    • Abstract: Publication date: Available online 24 August 2018Source: Case Studies in Thermal EngineeringAuthor(s): Amr Owes Elsayed This paper presents an attempt to improve the thermal performance of the absorber plate in photovoltaic solar systems by introducing novel configurations of pin fins. The cross-sectional area of these pins varies along the pin length producing small bulges with regular geometric shapes. The objective of changing the pin profile is to increase the heat transfer area and to produce a better mixing effect in the passages of the cooling fluid. Three shapes of bulges (diamond, cylinder and circular rings) have been employed to produce three forms of multi-bulges pin. The novel pins have been investigated under the influence of steady laminar forced convection flow. The effect of fin design on the absorber heat dissipation behavior has been studied and reported. The numerical model has been carried out by using CFD Fluent software. Finite volume technique is used and SIMPLE algorithm is applied. The thermal performance is presented in terms of surface temperatures of fin and plate, thermal efficiency of the absorber and average Nusselt number. In comparison with conventional pin fins, the results showed that the proposed pin fins indicate a good insight in the heat dissipation process and more effective in thermal performance.
  • Bree's diagram of a functionally graded thick-walled cylinder under
           thermo-mechanical loading considering nonlinear kinematic hardening

    • Abstract: Publication date: Available online 22 August 2018Source: Case Studies in Thermal EngineeringAuthor(s): Mohsen Damadam, Reza Moheimani, Hamid Dalir, Ali Nayebi In this paper, elasto-plastic analysis of a thick-walled cylinder made of functionally graded materials (FGMs) subjected to constant internal pressure and cyclic temperature gradient loading is carried out using MATLAB. The material is assumed to be isotropic and independent of temperature with constant Poisson's ratio and the material properties vary radially based on a power law volume function relation. The Von Mises’ yield criterion and the Armstrong-Frederick nonlinear kinematic hardening model were implemented in this investigation. To obtain the incremental plastic strain, return mapping algorithm (RMA) was used. At the end, the Bree's interaction diagram is plotted in terms of non-dimensional pressure and temperature which represents an engineering index for optimum design under thermo-mechanical loading.
  • Numerical optimization on thermal performance characteristics of interior
           walls based on air-conditioning intermittent running

    • Abstract: Publication date: Available online 20 August 2018Source: Case Studies in Thermal EngineeringAuthor(s): Xi Meng, Wentao Hu, Ying Cao, Yisheng Huang, Junfei Du, Yanna Gao When the air-conditioning runs intermittently, there may be the large temperature differences of the indoor air in two adjacent rooms due to the air-conditioning different running behaviors. Under this condition, a lot of the cold quantity was lost through interior walls and then the large cooling load was formed by interior walls. Aimed to this, six typically-employed interior walls were built to compare their thermal performance characteristics under air-conditioning intermittent running. The heat transfer model was built by the finite volume method and verified by the experimental data. The numerical results showed that the air-conditioning running behavior in the adjacent room had an observable influence on temperature response rates and heat flow values in inner surfaces. Compared with the solid brick walls, the daily cooling load formed by interior walls can be reduced by 26.1% for the foamed concrete wall and 12.7% for the hollow brick wall, respectively. When the temperature environment in the adjacent room was beneficial to improving the thermal response rate of the interior wall, the thin wall was the reasonable choice and whereas, the thick wall was the reasonable one.
  • Thermal and hydraulic characteristics of turbulent nanofluids flow in
           trapezoidal-corrugated channel: Symmetry and zigzag shaped

    • Abstract: Publication date: Available online 14 August 2018Source: Case Studies in Thermal EngineeringAuthor(s): Raheem K. Ajeel, W. Saiful-Islam, Khalid B. Hasnan Thermal and hydraulic characteristics of turbulent nanofluids flow in a trapezoidal-corrugated channel are numerically investigated by implementing the finite volume method to solve the governing equations. The adiabatic condition for the straight walls, constant heat flux for the corrugated walls, and two configurations of trapezoidal channel symmetry and zigzag shape were examined. The performance of a trapezoidal-corrugated channel with four different kinds of nanofluids ( ZnO, Al2O3, CuO, and SiO2), with four various nanoparticle volume fractions of 2%, 4%, 6% and 8% using water as base fluid is thoroughly analyzed and discussed. The nanoparticles diameter, another parameter is taken into consideration, varied from 20 to 80 nm. Results show that the symmetry profile of trapezoidal-corrugated channel has a great effect on the thermal performance compared with a straight profile and zigzag profile. The Nusselt number dropped as the nanoparticle diameter grew; however, it grew as the nanoparticle volume fraction and Reynolds number dropped. The best improvement in heat transfer among the nanofluids types was by SiO2-water. The present investigation uncovers that these trapezoidal symmetry-corrugated channels have favorable circumstances by utilizing nanofluids and in this manner fill in as a promising contender for incorporation in more compact heat exchanger devices.
  • Heat transfer enhancement and pressure drop of Fe3O4 -water nanofluid in a
           double tube heat exchanger with internal longitudinal fins

    • Abstract: Publication date: Available online 13 August 2018Source: Case Studies in Thermal EngineeringAuthor(s): Mohammad. Sikindar Baba, A.V.Sita Rama Raju, M.Bhagvanth Rao Use of internal fins in tubes of heat exchangers is a good practice for heat transfer enhancement. This paper reports an experimental study of forced convective heat transfer in a double tube counter flow heat exchanger with multiple internal longitudinal fins using Fe3O4 –water nanofluid.The convective heat transfer enhancement and pressure drop are investigated for the nanofluid flowing in a horizontal circular tube with internal longitudinal fins under turbulent conditions (5300
  • Numerical investigation of V-groove air-collector performance with
           changing cover in Bangi, Malaysia

    • Abstract: Publication date: Available online 4 August 2018Source: Case Studies in Thermal EngineeringAuthor(s): Idris Zulkifle, Ali H.A. Alwaeli, Mohd Hafidz Ruslan, Zahari Ibarahim, Mohd Yusof Hj Othman, Kamaruzzaman Sopian Air-based solar collectors are the simplest forms of flat plate solar collectors; without complications of introducing water or nanofluids into the process. They are used to raise the entering atmospheric air temperature to a level where it can be used for different low and medium temperature applications. The main components of their design are the collector, absorber and airflow arrangement. However, they exhibit the lowest efficiencies among other collectors. Hence, V-groove absorber designs are implemented to raise the thermal efficiency of air collectors. In this paper, a parametric study on the thermal performance of single-pass solar air collector with a v-groove absorber has been conducted using theoretical model and ran numerically using an excel sheet. The v-groove will enhance the convective heat transfer of the collector; as it has superior performance to flat-plate collectors. Two different cover designs are proposed; one with glass cover and the other with Fresnel lens cover. A comparison of different parameters is presented for various design conditions and operating conditions to drive the efficiency with respect to mass flowrate and incident solar radiation. This paper differs from other works in the literature in that it presents comparison between Fresnel lens and glass cover for V-groove single pass air heater. The results obtained shows that at solar irradiance of 755 W/m2 the collector covered with Fresnel less has the highest efficiency value of 71.18% compared to solar collectors with glass which has efficiency 54.10%. The mass flowrate contributed to efficiency enhancement. Moreover, a case study for Bangi, Malaysia was conducted to numerically test the performance of the two types using real-data from an outdoors test. Highest achieved temperatures from both collectors were around 35.85 °C for the glass-covered type and 38.39 °C for the Fresnel lens covered type.
  • Performance Analysis of Shell and Tube Heat Exchanger: Parametric Study

    • Abstract: Publication date: Available online 29 July 2018Source: Case Studies in Thermal EngineeringAuthor(s): Ammar Ali Abd, Mohammed Qasim Kareem, Samah Zaki Naji Enhancement of heat transfer through shell and tube exchangers stills taking high attention by researchers. The present work investigated the effect of shell diameter and tube length on heat transfer coefficient and pressure drop for shell side with both triangular and square pitches. In addition, the effect of baffle spacing and cutting space on heat transfer coefficient and pressure drop were studied. Moreover, standards fouling rates used for both shell and tube sides to estimate the reduced heat transfer. Increasing shell diameter with a triangular pitch and pull-through floating head recorded 3% increasing in heat transfer coefficient for only 0,05 m increasing in shell diameter. While 2.8% increase in heat transfer coefficient for shell side by 0.05 m increasing in shell diameter with split-ring floating head and square pitch. Heat transfer coefficient for shell side reduced by 15.15% by increasing baffle space by 0.2 from shell diameter and the pressure drop by 41.25%. Increasing cutting space from 15% to 25% decreases heat transfer coefficient by 5.56% and the pressure drop diminished by 26.3%. Increasing tube length by 0.61 m leads to enhance the heat transfer coefficient by 31.9% and pressure drop by 14.11% for tube side. For shell side, increasing tube length by 0.61 m gives 2.2% increasing in heat transfer coefficient and 21.9% increasing for pressure drop. Fouling resistance change on shell side shows a high effect on heat transfer more than same rate change on the tube side. Based on the result, this study can help designers to quick understand of each parameter effect on heat transfer into shell and tube exchangers.
  • Pyrolysis behavior and kinetics of corn residue pellets and eucalyptus
           wood chips in a macro thermogravimetric analyzer

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Thossaporn Onsree, Nakorn Tippayawong, Anqing Zheng, Haibin Li Pyrolysis of corn residue in pellet form and eucalyptus wood in chip form was conducted on a continuously weighing fixed bed reactor acting as a macro thermogravimetric (TG) analyzer with 40 ± 1.0 g of sample loading under high purity nitrogen environment. Effect of heating rate (5, 10, and 15 °C/min) was investigated and pyrolysis behaviors of the pellets and wood chips were also compared with those performed on a typical TG analyzer. Experimental results showed that bigger particle size and higher heating rate significantly delayed the pyrolysis reaction, meanwhile the heating rate affected the characteristic temperatures of the pellets and wood chips more than the smaller size. By differential derivative TG technique, the pyrolysis behaviors could be divided into three stages. Within the main stage of pyrolysis process, only a peak could be differentiated clearly in the derivative TG curve, accounted for approximately 67–81% of weight loss. Flynn-Wall-Ozawa method was used to calculate the activation energy against conversion of reaction on the whole temperature domain. It was found that the activation energy values from the macro TG analyzer, which were 60–70 and 59–71 kJ/mol with average values of 64 and 62 kJ/mol for the pellets and wood chips, respectively, were about four times lower than that obtained from the typical TG analyzer.
  • Hybrid semi analytical method for geothermal U shaped heat exchanger

    • Abstract: Publication date: Available online 24 July 2018Source: Case Studies in Thermal EngineeringAuthor(s): P. Jalili, D.D. Ganji, S.S. Nourazar In this paper, convective-conductive heat transfer processes between the all components of geothermal borehole heat exchanger (BHE) such as pipe-in, pipe-out and grout have been studied. A set of coupled partial differential equations subjected to general initial and boundary conditions are governed to this problem. Modified Homotopy perturbation method (MHPM) is a hybrid of discrete Fourier Transform, spectral analysis and Homotopy Perturbation Method that is developed in order to solve the partial differential equations of geothermal borehole systems. The results of MHPM are compared with the numerical solution for validation and, furthermore, the effectiveness and accuracy of the applied method have been shown.
  • Analysis on the Influence of the Smoke Block Board on the Entrainment
           Phenomena near a Mechanical Exhaust Vent

    • Abstract: Publication date: Available online 24 July 2018Source: Case Studies in Thermal EngineeringAuthor(s): Zhisheng Xu, Hongguang Chen, Lu He, Jiaming Zhao, Qiulin Liu, Baochao Xie In this study, the Fire Dynamics Simulator (FDS) numerical simulation method is adopted to analyze the influence of various smoke block board sizes, heat release rates (HRR) and exhaust velocities on the smoke entrainment near a mechanical exhaust vent. The results indicate that the smoke extraction performance of the board-coupled shaft is influenced by the coordination of the smoke block board layout, the heat release rate and exhaust velocity. Besides, the reasonable size of the board can effectively reduce the air entrainment and achieve the best smoke exhaust efficiency. When the board size is smaller than the exhaust vent size, there will be an inefficient exhaust smoke. When the board size is larger than the exhaust vent size, the exhaust smoke efficiency increases rapidly with the increase in the board size. In addition, the exhaust efficiency is insensitive to the HRR under the same board. However, the exhaust velocity exerts a significant effect on the layered stability and smoke extraction performance near the exhaust vent.
  • Validated mathematical models of a solar water heater system with
           thermosyphon evacuated tube collectors

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): C. Wannagosit, P. Sakulchangsatjatai, N. Kammuang-lue, P. Terdtoon An evacuated tube solar water heater system using thermosyphon heat exchange was experimentally and theoretically investigated. Solar radiation and ambient temperature data from Chiang Mai Province were used as the modeling system by an Explicit Finite Difference Method (EFDM). The experimental setup consisted of 8 evacuated tube collectors (ETCs) with thermosyphon diameters of 15.88 mm for the evaporator and 22.22 mm for the condenser. Lengths of the evaporator, adiabatic, and condenser sections were 1700 mm, 150 mm and 100 mm, respectively. Mathematical model results of both thermal resistance method and EFDM were validated by experimental results. Theoretical results for temperature and thermal efficiency concurred with experimental results and previous research. Experimental result, thermal resistance method and EFDM results indicated that maximum temperature of hot water occurred at 4:00 p.m. as 65.25 °C, 71.19 °C, and 69.46 °C, respectively. Thermal efficiency of the solar water heater system was 58.28% of the experimental result, 55.97% of the thermal resistance method and 57.60% of the EFDM result. EFDM provided better accuracy than the thermal resistance method by 2.97%.
  • An investigation of Dynamic Behavior of the Cylindrical Shells under
           Thermal Effect

    • Abstract: Publication date: Available online 19 July 2018Source: Case Studies in Thermal EngineeringAuthor(s): Adawiya Ali Hamzah, Hussein K. Jobair, Oday I. Abdullah, Emad Talib Hashim, Laith A. Sabri Study the vibration characteristics of the cylindrical shell is considered a very important issue, because of the cylindrical shells are used for different applications in engineering fields such as missiles, electric motors, rocketry, etc. In different applications, the cylindrical shells have produced a high level of noise and vibration that effect on the behavior and performance of the systems. In some cases, when those systems work under these conditions for enough time, this will lead the systems to failure or at least change the situation of those systems from stable zone to unstable zone. In this paper, the finite element method was used to investigate deeply the vibration characteristics of cylindrical shells under different surrounding temperatures. Furthermore, the effect of thickness on the dynamic characteristics was investigated.
  • Studies of the unavoidable exergy loss rate and analysis of influence
           parameters for pipeline transportation process

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Qinglin Cheng, Anbo Zheng, Lu Yang, Hao Wu, Lili Lv, Hongjun Xie, Yang Liu According to the exergy balance relationship among the various items in the crude oil transportation process system, the exergy balance equation is established and each exergy loss is calculated. In a sense, the essence of exergy analysis method relies on the calculation and the analysis of system exergy loss. The unavoidable exergy loss is defined based on the required minimum exergy loss from the technology standpoint during the pipeline conveying process. In order to truly reflect the degree of effective energy utilization, this article puts forward the unavoidable exergy loss rate as evaluation index, which is based on the exergy analysis criterion consisted by exergy loss coefficient and exergy loss rate. Taking an oil pipeline as an example, the changes of the unavoidable exergy loss are studied under different designed parameters. And the unavoidable thermal exergy loss is the dominant position. Change situations of the unavoidable exergy loss rate are explored. Through analysis, the trend and the regularity of the unavoidable total exergy loss rate are identical with the unavoidable thermal exergy loss rate. Then the orthogonal experiment method is used to compare the different influence degrees to the pipeline unavoidable exergy loss rate. The results are as follows: diameter, insulation thickness and buried depth, which can provide the reference for the energy-saving transportation of crude oil pipeline.
  • Assessment of heat transfer and fluid flow characteristics within finned
           flat tube

    • Abstract: Publication date: Available online 17 July 2018Source: Case Studies in Thermal EngineeringAuthor(s): Aadel A.R. Alkumait, Maki H. Zaidan, Thamir K. Ibrahim In this paper, the heat transfer and flow characteristic of air over flat finned tube with perforated and non-perforated fin have been carried out numerically. The mesh generation and finite volume analyses have been conducted using Ansys 15 with a RNG k–e turbulent model to estimate heat transfer coefficient and pressure drop. The free stream velocity ranging between 3,4,5,6, and 7 m/s have been applied for all cases in the simulation and verified with the available data. A satisfactory agreement was found between the percent results and the references with a maximum deviation of 7% for the finned circular tube with solid fin. The results present a considerable enhancement in Nusselt number with using perforation technique, where the perforation provide 8.5%, 13.6% and 18.4% enhancement using circular, square and triangular perforation respectively. Triangular perforation model offers a considerable finding due to the increment in the Nusselt number comparing to the pressure drop.
  • Experimental and numerical studies on ceiling maximum smoke temperature
           and longitudinal decay in a horseshoe shaped tunnel fire

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Yunji Gao, Guoqing Zhu, Sinian Gu, Haijun Tao, Yongchang Zhao The present paper investigates the ceiling maximum smoke temperature and longitudinal decay in tunnel fires using a horseshoe shaped 1:3.7 scale-model tunnel constructed by concrete and a full-scale model tunnel established by SIMTEC for the first time. The maximum smoke temperature beneath the ceiling and the longitudinal temperature profiles were obtained and analyzed. The major conclusions are summarized as follows: The ceiling maximum smoke temperature rise right above the fire source is directly proportional to the terms of Q2/3/Hf5/3 and the ceiling maximum smoke temperature decreases as a sum function of two exponential equations of horizontal distance. Modified equations are proposed for maximum smoke temperature rise beneath the ceiling and longitudinal temperature decay, and the predictions show a good agreement with the values measured by experiments and numerical simulations. The results obtained by numerical simulations agree well with experimental results, and SIMTEC is reasonable to simulate the tunnel fires to predict the temperature profiles. The results are of important significance for tunnel fire safety and personnel evacuation.
  • Optimisation of tilted angles of a photovoltaic cell to determine the
           maximum generated electric power: A case study of some Iraqi cities

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Akeel M. Ali Morad, Ali K. Shaker Al-Sayyab, Mohammed A. Abdulwahid This work was carried out to predict both the monthly and yearly optimum tilt angle for the photovoltaic cells that are located in Baghdad (latitude 33°20′), Diyala (33°14′), and Tikrit (34°35′). These Iraqi cities were selected based on their geographical location. Mathematical models were used and programmed by engineering equation solver, EES, to find the optimum tilt angle, depending on the maximum solar power intensity obtained; the tilt angle varied within a range from 0° to 90°. The results show that the optimum tilt angle for all these cities is the same for 31°. The monthly tilt angle was different from one month to another.
  • Thermal aspects of Carreau fluid around a wedge

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Usman Ali, Khalil Ur Rehman, M.Y. Malik, Iffat Zehra The Carreau viscosity model for a moving wedge with heat generation/absorption along with chemically reactive species has not been debated until yet. Therefore, this communication support these specifications in addition with steady boundary layer flow through a wedge. For this purpose, the mathematical model is constructed in terms of coupled partial differential equations and then sorted out in a numerical way with the aid of Runge-Kutta Fehlberg technique chartered with shooting scheme. To inspect the effects of physical parameter upon temperature and concentration, graphs are plotted. The temperature is examined for positive and negative values of heat generation parameter. The temperature profile enhances for the positive values while the influence of negative values show the declined nature. Further, the concentration gets diminished on chemical reaction parameter.
  • Effect of interfacial thermal resistance and nanolayer on estimates of
           effective thermal conductivity of nanofluids

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Ali Khodayari, Matteo Fasano, Masoud Bozorg Bigdeli, Shahin Mohammadnejad, Eliodoro Chiavazzo, Pietro Asinari Colloidal suspensions of nanoparticles (nanofluids) are materials of interest for thermal engineering, because their heat transfer properties are typically enhanced as compared to the base fluid one. Effective medium theory provides popular models for estimating the overall thermal conductivity of nanofluids based on their composition. In this article, the accuracy of models based on the Bruggeman approximation is assessed. The sensitivity of these models to nanoscale interfacial phenomena, such as interfacial thermal resistance (Kapitza resistance) and fluid ordering around nanoparticles (nanolayer), is considered for a case study consisting of alumina nanoparticles suspended in water. While no significant differences are noticed for various thermal conductivity profiles in the nanolayer, a good agreement with experiments is observed with Kapitza resistance ≈10−9 m2K/W and sub-nanometer nanolayer thickness. These results confirm the classical nature of thermal conduction in nanofluids and highlight that future studies should rather focus on a better quantification of Kapitza resistance at nanoparticle-fluid interfaces, in order to allow bottom up estimates of their effective thermal conductivity.
  • Numerical evaluation of the effects of fire on steel connections; Part 1:
           Simulation techniques

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Rohola Rahnavard, Robert J. Thomas Steel connections are used to connect between beam and column in steel moment frame structures. As of present time, there is a huge lack of understanding of the performance of steel connections and their response to fire especially the uncontrolled fires. Therefore, in this paper, by using a finite element program ABAQUS and with the static analysis of coupled temperature- displacement and to fully understand the behavior of such connection under the fire scenario, developed a temperature-dependent models for different types of steel connections are implemented. Finite Element Analyses (FEA) of selected experimental models are performed to verify the implementation of these models. Fully detailed, field-variable-dependent conductivity element models of the connections are developed, and analyses are performed to determine the effects of heat on the behavior of the materials in the elastic and plastic areas are considered. Moreover, severe deformation in the nonlinear region was investigated.
  • Effect of the particle size of pulverized olive cake on combustion
           parameters in Stirling engine in Morocco

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): N. Rassai, N. Boutammachte, H. El hassani, A. Al Mers, El Mostapha Boudi, A. Bekraoui Morocco is one of the richest countries with olive tree. Annually, about 675,000 t of Olive Cake are produced and injected which leads to damaging the environment especially the groundwater as well as the water table itself. To remedy this problem, and because olive cake has a high caloric value, the idea of this paper comes to valorize this waste through the Stirling engine in order to produce clean energy with low greenhouse emissions.To fulfill this purpose, the impact of the particle size of pulverized olive cake (OC) on the flow behavior and combustion parameters in a 3D vertical chamber was investigated. The spherical OC particles are injected through two injectors perpendicularly to the air inlet jets. Two particle sizes are chosen to conduct this study (PS1, PS2). The numerical approach is based on Reynolds averaged Navier–Stokes (RANS) method using the realizable k–ε turbulence model. For gas phase a non-premixed combustion model is used, and for the discrete second phase a Lagrangian approach is chosen. Temperature distribution, flow topology, velocity contours, and species concentrations profiles in the burner are obtained for the two cases. Results show that the first case particle size gives optimal results and is more suitable for this study.
  • Some particular design considerations for optimum utilization of under
           floor heating systems

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): S. Oubenmoh, A. Allouhi, A. Ait Mssad, R. Saadani, T. Kousksou, M. Rahmoune, M. Bentaleb This paper aims at studying the thermal behavior of an under floor heating system via CFD calculations. The results have discussed some important parameters that need to be controlled for an appropriate operation of the system. These parameters include the velocity inside the pipes, inlet temperatures and the patterns of the tubing form. A new parameter to measure the floor thermal homogeneity has been introduced and evaluated. It is found that, generally, the modulated spiral configuration is the best configuration allowing less pressure losses and better thermal homogenization.
  • Optical efficiency measurement of solar receiver tubes: A testbed and case

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Rafael López-Martín, Loreto Valenzuela Knowledge of the parabolic-trough collector (PTC) solar receiver performance is essential in solar thermal power plants using this type of collector technology because it is the component responsible for collecting the solar radiation and transferring it in the form of thermal energy to the heat transfer fluid. Its performance depends on two parameters, heat loss and the optical efficiency of the solar receiver tubes. Therefore, the receiver optical efficiency must be known for correct sizing of a PTC solar field. This article presents an outdoor testbed developed to measure the optical efficiency of solar receiver tubes under real solar radiation conditions, including a detailed description of the system developed, working principle, test procedure, and performance results for two sample receiver tubes tested showing proper system functioning.
  • Numerical study on the effect of operating nanofluids of photovoltaic
           thermal system (PV/T) on the convective heat transfer

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Ali H.A. Al-Waeli, Miqdam T. Chaichan, Hussein A. Kazem, K. Sopian, Javad Safaei Photovoltaic (PV) collectors are replaced with hybrid photovoltaic thermal (PV/T) systems to establish an electrical and thermal yields. The main function of such design is to provide cooling for the solar cell by absorbing its temperature. This temperature is used for the thermal energy generation of this hybrid design. High electrical and thermal efficiencies are associated with PV/T's. In this study, mathematical analysis was used to examine the effect of the type of nanoparticles added (SiC, CuO, and Al2O3), and the type of base fluids (water, glycerin, and ethylene glycol) on the convection heat transfer of PV/T system. The solar simulator type 'MINI-EESTC' was modified to work as a PV/T was used in the practical part of the study.The numerical results showed the base fluid and the added nanoparticles' thermophysical properties effect on the convective heat transfer and pressure drop. Glycerin showed the maximum pressure drop while water indicated the minimal value. The addition of nano-SiC for the studied base-fluids afforded higher convective heat transfer than nano-CuO and nano-alumina. The validation of the numerical results with the practical one showed a good agreement.
  • The energy and economic target optimization of a naphtha production unit
           by implementing energy pinch technology

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Ali Manizadeh, Ashkan Entezari, Rouhollah Ahmadi In this paper, energy pinch analysis is implemented on the Naphtha Production Unit as an operating process plant. It endeavors to approach the current system to the maximum energy recovery (MER) design by providing several scenarios in the heat exchangers network. Furthermore, the economic analysis considering the initial investment and operating costs of the system was conducted in each scenarios to achieve a cost-effective system. The results obtained just from the pinch analysis optimization technique, indicate that reducing the heating and cooling loads do not reduce the total costs. Therefore, two objective optimization of minimization of the levelized cost of product (LCOP) as well as maximization of the overall energy performance of the system are concerned to find out the optimal scenario of the energy network layout. Here, retrofit of the maximum energy recovery design is performed to represent the energetical and economical optimal layout.
  • CFD-Based research on control strategy of the opening of Active Grille
           Shutter on automobile

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): JiaCheng Li, YaDong Deng, YiPing Wang, Chuqi Su, Xun Liu Active Grille Shutter is a very promising technology to improve the performance and fuel economy of automotive engines. The engine room temperature and the automobile aerodynamic resistance should both been considered when controlling the opening of the Active Grille Shutter. A very complete geometric model was built for exterior of an automobile and interior of its engine room at a scale of 1:1 with different openings of the Active Grille Shutter. An aerodynamic drag coefficient variation curve at different grille openings was obtained through simulation analysis, which coincided with the actual aerodynamic drag coefficient. Research was made on the Active Grille Shutter opening control strategy based on computational fluid dynamics method and with radiator's heat dissipating capacity and the automobile aerodynamic drag coefficient as the evaluation parameters. The Active Grille Shutter opening control strategy was obtained, which guarantees that the automobile aerodynamic resistance is the lowest at different travel speeds, and the engine room temperature is within the optimal range.
  • Hybrid thermal model of a synchronous reluctance machine

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Payam Shams Ghahfarokhi, Ants Kallaste, Anouar Belahcen, Toomas Vaimann, Anton Rassõlkin This paper presents a hybrid thermal modeling methodology to analyze the temperature performance of radial flux electrical machines. For this purpose, the 2D finite element model of the active part of the machine is coupled with a lumped parameters thermal circuit of the end-winding region. A synchronous reluctance machine is used to validate the proposed approach. The results from the proposed method are compared with the experimental ones, which are obtained from a prototype machine. The computations show that the 2D FE model underestimates the temperature rise in the machine as it does not account for the power losses in the end-windings. The hybrid model accounts for these losses as well as for the heat dissipation in the end-winding region.
  • Case study of MHD blood flow in a porous medium with CNTS and thermal

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Asma Khalid, Ilyas Khan, Arshad Khan, Sharidan Shafie, I. Tlili This articles deals with unsteady MHD free convection flow of blood with carbon nanotubes. The flow is over an oscillating vertical plate embedded in a porous medium. Both single-wall carbon nanotubes (SWCNTs) and multiple-wall carbon nanotubes (MWCNTs) are used with human blood as base fluid. The problem is modelled and then solved for exact solution using the Laplace transform technique. Expressions for velocity and temperature are determined and expressed in terms of complementary error functions. Results are plotted and discussed for embedded parameters. It is observed that velocity decreases with increasing CNTs volume fraction and an increase in CNTs volume fraction increases the blood temperature, which leads to an increase in the heat transfer rates. A validation of the present work is shown by comparing the current results with existing literature.
  • Experimental study on upward flame spread characteristics of external
           thermal insulation material under the influence of porosity

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Qing xuan Meng, Guo qing Zhu, Miao miao Yu, Zhen huan Liang Upward flame spread characteristics over extruded polystyrene (XPS) foams with different porosities has been analyzed through experiments. In this paper, the average flame height and average maximum flame temperature first rise and then drop with increasing porosity, which is affected by the fuel and oxygen competition mechanisms. For P (the porosity of XPS samples) ≤ 35%, the positive effect of pores plays a dominant role; the average flame height and average maximum flame temperature increase with the increasing porosity. While the negative effect of pores plays a dominant role when P > 35%, causing the average flame height and average maximum flame temperature decrease with the increasing porosity. Modeling and experiments were conducted to study the heat flux from flame. The value of radiation is obviously higher than convection through formula derivation and the experimental results have high similarity with the theoretical results.
  • Effect on TEG performance for waste heat recovery of automobiles using MgO
           and ZnO nanofluid coolants

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Dhruv Raj Karana, Rashmi Rekha Sahoo Present study deals with the theoretical analysis for the performance comparison of automotive waste heat recovery system with EG-W, ZnO and MgO nanofluidas coolants for TEG system. Effects on performance parameters i.e power output, conversion efficiency and circuit voltage of TEG system with exhaust inlet temperature, total area of TEG, Reynolds number and particle concentration of nanofluids for TEG system have been investigated. Theoretical performance analysis revealed enhancement in output power, conversion efficiency and voltage of the TEG system for MgO nanofluid, followed by ZnO and EG-W coolants. The power output and the conversion efficiency using 1% vol. fraction MgO nanofluid at an inlet exhaust temperature of 500 K, were enhanced by 11.38% and 10.95% respectively, as compared to EG-W coolants. The further increase in nanofluid concentration exhibited a progressive effect on output performance of the TEG system. Further analysis shows that there exists an optimal total area of TEGs for maximum output performance of the system. With MgO nanofluid as a coolant, total area of TEGs can be reduced by up to 33% as compared to EG-W, which would bring significant convenience for the arrangement of TEGs and reduce the cost of TEG system.
  • Thermal characteristic research of associated power devices based on
           three-level inverters and power-loss calculation

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Shi-Zhou Xu, Chun-Jie Wang, Fang-Li Lin, Xiang-Yu Zhu, Xue Xia To reduce the size and improve the power density of three-level inverters, two or more associated power devices are assembled on the same heatsink, which, however, has a great influence on the thermal characteristics of heatsink because of heat accumulation, and is the main cause of thermal faults. The NPC (Neutral Point Clamped) three-level inverter was taken into this paper as a research target and platform. The dynamic power losses of two power devices were calculated firstly according to the working condition and then put into the solid model. Secondly, the thermal characteristics of heatsink with associated power devices on it were analyzed through finite element analysis, and the temperature rise of power devices were studied as well. Finally, the thermal characteristic experiment was conducted on a 1 MW NPC three-level inverter platform, and the results proved the effectiveness of the research method on thermal characteristics of heatsink with associated power devices.
  • Magneto-Marangoni nano-boundary layer flow of water and ethylene glycol
           based γ Al2O3 nanofluids with non-linear thermal radiation effects

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): N. Vishnu Ganesh, Ali J. Chamkha, Qasem M. Al-Mdallal, P.K. Kameswaran For the first time, a numerical investigation is performed to study the influences of magnetic field on Marangoni boundary layer flow of water and ethylene glycol based γ Al2O3 nanofluids over a flat surface in the presence of non-linear thermal radiation. Experimental based thermo-physical properties and an effective Prandtl number model for γ Al2O3 nanofluids are considered to analyse the Marangoni convection. To study the magnetic field effects, the electric conductivities of both nanoparticles and base fluids are taking into account. Numerical solutions of resulted equations are obtained using fourth order Runge-Kutta method with shooting technique. The combined effect of magnetic parameter with other involved parameters is discussed on velocity and temperature distributions and the local Nusselt number via graphical illustrations.
  • Lifted flame property and interchangeability of natural gas on partially
           premixed gas burners

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Zhiguang Chen, Chaokui Qin, Pengfei Duan The relationship between lifted flames and burner head temperature of partially premixed gas burners supplied by various natural gas sources was investigated, and the application of AGA(American Gas Association) lifting limit for Chinese domestic gas burners was studied. Results showed that lifted flames became more seriously with the burner head temperature decreasing, also with the increase of lift height of flames, it would lead to reduce the burner head temperature, eventually the burner head would reach the thermal equilibrium state which maintained stable flames and temperature. The lifting limit curve of partially premixed gas burners was only one under the same gas source, and it only depended on the burner structures and gas source characteristics, but nothing to do with the burner head temperature. The gas source with lower Wobbe index and calorific value made the burner appearing lifted flame more easily. Comparing with the experiment results and AGA lifting index prediction, it suggested that the limits of AGA lifting index IL≤ 1.10 should be change into IL≤ 1.05 using in China.
  • Micropolar nanofluid flow and heat transfer between penetrable walls in
           the presence of thermal radiation and magnetic field

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): M. Alizadeh, A.S. Dogonchi, D.D. Ganji Flow and heat transfer of MHD micro-polar nanofluid in a channel with penetrable walls and considering thermal radiation impact are investigated. A similarity transformation is utilized to transmute the governing momentum and energy equations into non-linear ordinary differential equations with the appropriate boundary conditions. The gained non-linear ordinary differential equations are solved by Duan–Rach Approach (DRA). This method allows us to detect a solution without applying numerical methods to evaluate the unspecified coefficients. The impacts of diverse active parameters such as the micro-polar parameter, the magnetic parameter, the volume fraction of nanofluid and the radiation parameter on the velocity and temperature profiles are examined. Furthermore, the value of the Nusselt number is calculated and presented through figures.
  • Magnetically stirring enhanced thermal performance of phase change

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Dao-Yu Sun, Si-Xin Yan, Zhi-Zhu He Here we report an active method to enhance the thermal performance of phase change material (PCM) based on magnetically-stirring method. The magnetic bead with small size embedded in the container filled with octadecanol, is driven to rotate by rotating magnetic field, and induce the forced convective heat transfer of the liquid octadecanol. We investigate the impact of rotating magnetic velocity, magnetic bead size, the distance between magnetic bead and rotating permanent magnet on the surface temperature of the simulated heating plate. The experimental results indicated that magnetically stirring obviously improve the heat transfer from liquid phase to solid phase of octadecanol and make simulated heat source keep a lower and smoother temperature platform. We also find that the best condition point could be determined by matching the rotation velocity for the given size of magnetic bead. These results are expected to provide insights into the design and optimization of latent heat thermal energy storage systems.
  • Influence of thermal contact on heat transfer from glowing firebrands

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Alok Warey The influence of thermal contact between a glowing firebrand and the target fuel bed on the resultant heat transfer into the fuel bed was investigated in this study. A zero dimensional (0-D) model for the firebrand coupled to a transient two dimensional (2-D) explicit finite difference model for the fuel bed were used simulate transient heat transfer from a firebrand deposited on a fuel bed. Two firebrand shapes, a disk shaped firebrand in contact with the fuel bed and a cylinder shaped firebrand with a protruding node in contact with fuel bed, were considered. A model was proposed to estimate the thermal contact resistance between the firebrand and the target fuel bed. Heat transfer from a cylinder shaped firebrand with two contact points was also investigated. The model developed in this study provided detailed information on the temperature distribution and thermal penetration depth in the target fuel bed. Predictions made by the model were in qualitative agreement with experimental data reported in the literature. The firebrand thermal contact resistance model presented in this study can be a useful tool to account for variations in firebrand shape and surface irregularities in both the firebrand and the target fuel bed.
  • Entropy generation in MHD mixed convection stagnation-point flow in the
           presence of joule and frictional heating

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): M.I. Afridi, M. Qasim, Ilyas Khan, I. Tlili This article looks at the second law analysis of MHD boundary layer stagnation-point flow past over linearly stretched sheet. The thermal boundary condition is supposed to be non-isothermal and the effects of friction and Joule heating have been analysed. By using similarity transformations, the model nonlinear partial differential equations in two independent variables are reduced to ordinary differential equations. The numerical techniques, namely shooting and fourth order Runge-Kutta are used to give a numerical solution. An expression for dimensionless entropy generation and Bejan number are obtained and computed using velocity and temperature profiles. The main objective of this article is to analyse the effects of a magnetic parameter, Prandtl number, Eckert number, stretching parameter, mixed convection parameter and dimensionless temperature parameter on the volumetric rate of entropy production and Bejan number. It is found that entropy generation increases with enhancing values stretching parameter and decrease with the increasing values of dimensionless temperature parameter.
  • Use of parabolic troughs in HVAC applications – Design calculations
           and analysis

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Khaled Chahine, Rabih Murr, Mohamad Ramadan, Hicham El Hage, Mahmoud Khaled The present work is concerned with the combination of solar energy systems with HVAC systems. Namely, the objective is finding a way of applying green energy concepts to HVAC systems. Particularly, solar concepts are employed to supply electrical power to HVAC systems. Hence, an innovative concept that permits the use of electrical energy provided by parabolic troughs to drive electrical components of the HVAC system is suggested. Thermal modeling along with governing equations of electricity production from parabolic troughs are presented. Calculations of the electrical power needed for HVAC system, showed that an order of magnitude of energy saving is attainable. Finally, the aforementioned concept was applied on a genuine case in Beirut city. It was shown that four mirrors with a 0.5 efficiency of the storage system are capable to drive the pumps of a HVAC system of a 4-floor building all over the year.Graphical abstractfx1
  • Detection of ammonia gas by Knudsen thermal force in micro gas actuator

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Ahmadreza Mahyari, M. Barzegar Gerdroodbary, M. Mosavat, D.D. Ganji Direct Simulation Monte Carlo (DSMC) method is applied to evaluate the performance of a new micro gas sensor (MIKRA) for mass analysis of ammonia in the rarefied gas. In order to simulate a rarefied gas inside the micro gas detector, Boltzmann equation is applied to obtain high precision results. This study performed comprehensive studies to reveal the main mechanism of force generation and applied this for the analysis of the gas mixture. Our findings show that value of generated Knudsen force significantly varies when the percentage of the NH3 varies in the mixture. According to obtained results, the maximum Knudsen force increases when the fraction of the ammonia decreases. Our findings reveal that the effect of gap size varies with the pressure of the domain. In addition, the increase of temperature gradient from 40 K to 100 K rises the maximum Knudsen force more than 400% on the shuttle arm.
  • Thermal analysis in Stokes’ second problem of nanofluid:
           Applications in thermal engineering

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Ilyas Khan, Kashif Ali Abro, M.N. Mirbhar, I. Tlili Present study is prepared to analyze the heat transfer for the Stokes’ second problem of nanofluid. Water is taken as base fluid and two types of nanoparticles namely copper (Cu) and silver (Ag) are suspended in it. Exact solutions for velocity field and temperature distribution have been investigated by utilizing the Laplace transform method and presented in the form simple elementary functions. The results lead to the few facts regarding the effects of rheological and pertinent parameters on the graphical illustrations. Heat transfer is decreased with increasing nanoparticles volume fraction. Hartman number and porosity have opposite effects on fluid motion. This study has several applications in thermal engineering.
  • Performance evaluation and parametric studies on variable nozzle ejector
           using R134A

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): B. Elhub, Sohif Mat, K. Sopian, A.M. Elbreki, Mohd Hafidz Ruslan, A.A. Ammar Computational fluid dynamics of variable nozzle ejector has been studied to determine the optimum nozzle exit position for reliable ejector cooling cycle operations. The flow rates of primary and secondary stream were varied to obtain the optimum entrainment ratio under different ranges of operating conditions.The refrigerant R134a was chosen based on the merit of its environmental and performance characteristics, the refrigerant was chosen because currently is used widely in air conditioning system. It was found that the computational fluid dynamics showed that the optimum positioning of nozzle exit position, which was based on the parameters such as pressure inlet variation the temperature inlet. The results obtained after the optimization of the results showed that the optimum nozzle exit position was found at 3 mm from the mixing chamber inlet when the operating conditions pressure inlet, secondary pressure inlet, primary temperature inlet and outlet pressure were at (18bar,6bar,373K,and5.6bar) respectively. Similarly, the range of entrainment ratio was varied between 0.24−1.283 at a constant area ratio, and at varied operating conditions.
  • Determination of effective moisture diffusivity and thermodynamic
           properties variation of regional wastes under different atmospheres

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Fernandez Anabel, Román Celia, Mazza Germán, Rodriguez Rosa During the thermal process to transform lignocellulosic wastes in energy, the drying process is an important stage because it requires energy and decreases overall process yield. Considering this process, moisture diffusivity is an important factor that is considered essential to understand for design, analysis, and its optimization. In this work, this parameter was analyzed at non-isothermal condition and considering the process under inert and oxidative atmospheres. Lower diffusivities were obtained under low heating rates, due to the disfavoring the moisture diffusion in the particles. Higher effective diffusivity (Deff) values were obtained when the drying is carried out under the atmosphere oxidative.Moreover, the thermodynamic parameters and DTA curves were determined. ∆H values are positive in all cases, showing that the drying process is endothermic. ∆G are positive and ∆S negative, indicating that the process is non-spontaneous. DTA curves show that the drying process is endothermic, according with the calculated ∆H.
  • The effect of multi-longitudinal vortex generation on turbulent convective
           heat transfer within alternating elliptical axis tubes with various
           alternative angles

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Hasan Najafi Khaboshan, Hamid Reza Nazif This study strives for a numerical examination of the turbulent flow and the heat transfer of water fluid flow in the alternating elliptical axis tube under various alternative angles. The purpose of this study is to increase the heat transfer by generating multi-longitudinal vortices along the tube flow. By increasing the rotation angle between pitches, the number of the formed multi-longitudinal vortices caused by the secondary flow increase from four to eight. This increase in the number of the multi-longitudinal vortices causes the cold fluid of the tube centre to have interaction in more paths with the hot fluid close to the wall and be mixed as well. This results in an increase of the heat transfer in this type of tubes. In addition, the results show that an improvement in the mean of average Nusselt numbers of alternating elliptical axis tube with the rotation angles of 40°, 60°, 80°, and 90° compared to the circular tube are 7.77%, 14.6%, 16.93%, and 24.42%, respectively. Finally, the correlations of the friction factor and the Nusselt number with the Reynolds number are presented for four AEA tubes with different pitches degree (40°, 60°, 80°, and 90°).
  • A numerical investigation on ethylene glycol-titanium dioxide nanofluid
           convective flow over a stretching sheet in presence of heat

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Kh. Hosseinzadeh, F. Afsharpanah, S. Zamani, M. Gholinia, D.D. Ganji In this article, TiO2-ethylene glycol nanofluid flow over a porous stretching sheet in presence of non-uniform generation or absorption of heat and convective boundary condition is investigated. The concentration of solute is set by the means of an isothermal model of homogeneous-heterogeneous reactions. The governing equations were simplified to ordinary differential equations and solved using Runge-Kutta-Fehlberg shooting method of fifth order. Effects of different variables such as nanoparticle volume fraction, porosity variable, and Schmidt number were studied and the results are graphically presented. The results showed that the stretching rate ratio has inverse effect of velocities in both directions. According to plots, nanoparticle volume fraction as well as convective heat intensity has a direct relation with wall heat flux, in the contrary, heat generation has an inverse effect on it.
  • Experimental analysis of using beeswax as phase change materials for
           limiting temperature rise in building integrated photovoltaics

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Razali Thaib, Samsul Rizal, Hamdani, T.M.I. Mahlia, Nugroho Agung Pambudi Indonesia has the potential of saving from 10% to 30% of energy in the commercial sector which consists of trade, hotels, restaurants, finances, government agencies, schools, hospitals, and communications. By simultaneously serving as building envelope material and power generator, BIPV systems can represent savings in the cost of materials and electricity. It reduce the use of fossil fuels and emission of ozone depleting gases, and also add architectural interest to buildings. However, the temperature rise poses a challenge for BIPV, given that it manifests itself in electrical efficiency and overheating. The experiments present in this study aim at understanding the behavior of the PV-PCM systems in realistic outdoor uncontrolled conditions to determine how effective they are. In addition, the PV-PCM systems were tried in the low latitude and hot climate of Banda Aceh, Indonesia. Experiments were conducted outdoors at the Engineering Faculty in Syiah Kuala University, located in Banda Aceh, Indonesia (05:57 N, 95.37 E). In this study, both paraffin wax and beeswax were used as a phase change material. The final results showed that the electrical efficiency of PV panels without PCM is ranged between 6.1% and 6.5%. While for PV panels with PCM the efficiency is ranged at 7.0–7.8%. This proved that the process of water cooling is capable of increasing the efficiency of PV panels.
  • Heat transfer phenomena on waste heat recovery of combustion stack gas
           with deionized water in helical coiled heat exchanger

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Rithy Kong, Thoranis Deethayat, Attakorn Asanakham, Tanongkiat Kiatsiriroat Theoretical and experimental studies on waste heat recovery of combustion stack gas and heat transfer phenomena of a fully developed laminar flow of deionized water in vertical helical coils were carried out with coil dimensions: tube diameter to coil diameter ,di/D=0.04−0.06 and pitch to coil diameter, p/D=0.1−0.25. The calculation of heat transfer data was based on countercurrent flow LMTD method. The result showed that deionized water (DI-water) possessed better heat transfer than that of normal water. The effect of coil pitch, coil diameter, and coiled tube diameter on heat transfer phenomena of helical coils had been discussed and a new set of correlation of heat transfer data was created and it could be found that the results from the correlation agreed well with the experimental data. In addition, the overall heat transfer coefficient between the hot exhaust gas and the heat transfer fluid in the helical coil was also considered. Smaller tube diameter gave better overall heat transfer coefficient at low water-side Reynolds number and when the Reynolds number was over 3500 the bigger tube diameter showed the advantage. Smaller coil diameter seemed to get better overall heat transfer coefficient at low water-side Reynolds number.
  • Thermo-physical aspects in tangent hyperbolic fluid flow regime: A short

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Khalil Ur Rehman, Ali Saleh Alshomrani, M.Y. Malik, Iffat Zehra, Muhammad Naseer The present attempt is made to report the flow regime characteristics of tangent hyperbolic fluid when both the magnetic field and heat generation effects are taken into account. The flow narrating differential equations subject to thermally stratified medium are transformed into a system of nonlinear ordinary differential equations. A computational algorithm is developed to offer a numerical solution of the flow problem. The physical outcomes against flow controlling parameters namely, curvature parameter, Weissenberg number, power law index, thermal stratification, heat generation and Prandtl number are discussed and illustrated via graphs and tables. The outcomes are certified by providing comparison with existing literature in a limiting sense.
  • Effect of cooled EGR on modified light duty diesel engine for combustion,
           performance and emissions under high pressure split injection strategies

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Gautam Edara, Y.V.V. Satyanarayana Murthy, Paleti Srinivas, Jayashri Nayar, Merigala Ramesh Environmental concerns demands light duty Engines to satisfy the stringent Euro VI emission norms. The aim of this study is to present the effect of cooled exhaust gas recirculation (EGR) on emission reduction. Tests are conducted on a modified single cylinder light duty diesel engine to run on high pressure common rail direct fuel injection. Diesel is injected directly in to the engine cylinder for both retarded and split injections at pressures of 200, 230, 250, 300 and 350 bar respectively. Cooled EGR is circulated along with intake air in to the inlet manifold of the engine for flow rates of 5% and 10%( wt/wt) of injected air respectively for both retarded and split injections. Single injection is retarded at − 11° ATDC and split injection consists of pilot injection at − 54°ATDC of 10% mass share and main injection at − 11°ATDC of 90% mass share. The result shows split injection (MPFI) decreases the ignition delay, In-cylinder combustion temperature and peak pressure for higher EGR flow rates compared to retarded single injection (SI) for all Injection pressure. Split injection reduced NOx from 1400 ppm to 200 ppm for 10% EGR flow rate at 350 bar injection pressure at full load operating conditions. Split injection at high Injection pressure decreases smoke by 10% as compared to retarded single injection. Test results show that there is trade-off exists between retarded and split injections at 350 bar injection pressure at full load conditions. Retarded injection has 33.61% brake thermal efficiency while split injection exhibits only 29.06% for 5% EGR flow rates. But higher EGR flow rates of 10% both retarded and split injection has nearly same brake thermal efficiency of 30.11%. Split injection reduced the combustion duration, ignition delay and exhaust gas temperatures for higher EGR flow rates compared to single retarded injection. The present research reveals that there exists an injection pressure map between the design operating pressure and maximum injection pressure. MPFI system under CRDI mode is very effective in reducing the NOx emissions with 10% EGR flow rates for maximum Injection pressure. While retarded SI injection is effective for moderate Injection pressure with the same EGR flow rates.
  • Nonlinear thermal radiation effect on magneto Casson nanofluid flow with
           Joule heating effect over an inclined porous stretching sheet

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): S.S. Ghadikolaei, Kh. Hosseinzadeh, D.D. Ganji, B. Jafari In this paper, mixed convection on MHD flow of casson nanofluid over a non-linearly permeable stretching sheet has been investigated and analyzed numerically. The effects of thermal radiation, chemical reaction, heat generation/absorption, viscous dissipation, suction and Joule heating are considered. The Brownian motion and thermophoresis phenomenon are used to model nanoparticles (Buongiorno's model). After converting PDEs governing the problem to ODEs, they have been solved by Runge-Kutta Fehlberg fourth-fifth order method. Obtained results of investigating the effects of different parameters changes on velocity, temperature, and concentration profiles are reported as diagrams. Fluid flow velocity reduction by increase in Hartman number (magnetic field parameter) is due to existence of Lorentz drag force against flow, flow velocity reduction due to increase in casson fluid parameter, increase in temperature profile due to increase in radiation parameter, and nanoparticle concentration profile reduction due to increase in chemical reaction parameter are some of valuable obtained results. Also, in final section of this paper effects of different parameters on skin friction coefficient, local Nusselt and Sherwood numbers are investigated that positive and ascending behavior for all three are reported.
  • New advancement of high performance for a combined cycle power plant:
           Thermodynamic analysis

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): M.N. Khan, I. Tlili A great amount of energy gets lost through the exhaust of simple, reheat and inter-cooling cycle. Sometimes, this energy is enough to run another cycle or can be used to heat the compressed air from the compressor to the combustion chamber which leads to an increase in the overall efficiency of the plant. Combined cycle is an alternative to utilize the lost energy. In this way, not only the efficiency of the plant increases but it also helps to reduce air pollution and global warming. This paper is a parametric analysis conducted in order to optimize the performance of combined cycle which involves the bypass valve. The result shows that gain in network output is about 45% when the temperature at the inlet of the turbine of topping cycle increases from 1000 K to 1400 K. The gain in net efficiency of the cycle is from 15% to 31% when the temperature at the inlet of the turbine of topping cycle increases from 1000 K to 1400 K. The bypass valve should be opened for small compression ratio and closed for high value of compression ratio.
  • Mathematical modeling and simulation of a solar agricultural dryer with
           back-up biomass burner and thermal storage

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Elieser Tarigan Solar drying is a cost-effective and environmentally friendly method for drying agricultural products. To design a proper solar dryer for specific products, thermodynamic relations for the dryer system need to be considered. Numerical simulations are commonly used for the design and operational control of dryers. This study presents the mathematical modeling and simulation of a solar agricultural dryer with back-up biomass burner and thermal storage. Thermodynamic and numerical simulations of the solar collector and drying chamber are performed, while back-up heater (biomass burner) operation is simulated with a computational fluid dynamics (CFD) simulation. For the solar collector, it was found that the presence of a glass cover significantly increases the temperature of the collector; however, increasing the number of glass covers from one to two does not significantly affect the temperature. Variation in thickness of the back insulation has negligible effects, especially for thicknesses over 3 cm. The results show that there is a small difference in temperature between the bottom three trays, while the temperature on the top tray is significantly higher. The CFD simulation showed that the average drying air temperature in the drying chamber was 56 °C, which is suitable for the drying of agricultural products.
  • Heat release analysis and thermal efficiency of a single cylinder diesel
           dual fuel engine with gasoline port injection

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Chondanai Vipavanich, Sathaporn Chuepeng, Sompol Skullong Cleaner diesel engines have been successively developed to meet a compromised solution for issues concerning performance and emission regulation. Combustion and exhaust gas after-treatment technologies are exhaustively settled to resolve those problems. A key improvement of the emissions is diesel dual fuel combustion that increases operating range of the premixed combustion. The main aim of this work is to explore the heat release, fuel consumption, and thermal efficiency of a single cylinder diesel dual fuel engine. An intake port fuel injection of gasoline with the flow rates between 0 and 0.06 g/s was accomplished to form a premixed charge prior to induction into the combustion chamber and ignition by the main diesel fuel. The engine was operated on medium load at 1700 rpm without exhaust gas recirculation. An engine indicating system composed of a cylinder pressure transducer and a shaft encoder was used to investigate combustion characteristics based on the first law of thermodynamics. The combustion of higher gasoline pre-mixer increased heat release rates, shortened combustion duration, and increased maximum cylinder pressure than neat diesel combustion. Increasing gasoline proportion reduced the diesel fuel and total fuel consumptions. This enhanced the engine thermal efficiency over the diesel baseline combustion.
  • Numerical simulation for the heat transfer behavior of oil pipeline during
           the shutdown and restart process

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Lixin Wei, Qimeng Lei, Jian Zhao, Hang Dong, Lin Yang Mathematical models for the heat transfer behavior of the oil pipeline during shutdown and restart are established. And the finite difference and finite volume method are used to disperse the mathematical models to investigate the heat transfer characteristics of the thermal system. Five simulation cases are executed to obtain some findings. During restart, the pipeline can be divided into three regions with each region has a certain temperature changing trait. And the increasing of temperature on certain position has two stages and each stage has a different temperature evolution due to the movement of remain cold oil and entering of hot oil. The surrounding soil has the analogical temperature evolution in contrast to the crude oil except some thermal hysteresis exists. And a thermal influence region is also found around the pipeline. The influence of restart flow and temperature on the oil pipeline is also investigated. There is a worthy of note that in case that the restart flow is lower than a certain value, there may be appears a period of time that the oil temperature continues to decrease although the pipeline has been restarted. This condition increases the risk of oil gelatinization.
  • Thermal and concentration aspects in Carreau viscosity model via wedge

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Usman Ali, Khalil Ur Rehman, Ali Saleh Alshomrani, M.Y. Malik The current pagination reports both the heat and mass transfer aspects subject to two dimensional steady flow over a moving wedge for the Carreau viscosity model with infinite shear rate viscosity. The results are reported for the both shear thinning and shear thickening cases. The set of ordinary differential equations has been obtained by transforming the nonlinear partial differential equations (manipulating fluid flow) with the aid of admissible transformation and then sorted out numerically by using the Runge-Kutta Fehlberg method merged with shooting proficiency. The Carreau fluid temperature reduces via higher values of viscosity ratio parameter for shear thickening case while Carreau fluid concentration shows decline towards wedge angle for both shear thinning and thickening cases.
  • Numerical simulation of fluid solid coupling heat transfer in tunnel

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Du Cuifeng, Bian Menglong In order to obtain the fluid solid coupling heat transfer law of the roadway, the coupled heat transfer between rock and air is analyzed through Fluent, Steady-State Thermal and Static Structural module in ANSYS. The heat flux and thermal strain of rock and the influence of air which under different wind speed and inlet temperature are obtained. The heat flux in the rock is approximately uniformly distributed in the circular ring shape, and the distribution of the heat flux from high to low is as follows: the roadway wall> rock mass> air. The heat flux of the rock near the wall is greater than that in the far side wall. The maximum is located at the wall, and the value is 160 W/m2. The thermal strain of rock is greatly influenced by local heat source, and the maximum value is 5.1 × 10−5 m/m in of rock is greatly influenced by local heat source, and the maximum valin of rock is greatly influenced by local heat source, and the maximum val. Compared with the loader, the hydrothermal water which has greater influence on the temperature of rock and wind can be regarded as the focus on the control of heat damage.
  • Numerical thermodynamic model of alpha-type Stirling engine

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Khaled M. Bataineh The objective of this study is to develop accurate practical thermodynamic model for alpha-type Stirling engine with Ross Yoke mechanism. Thermal, pumping, and regeneration loses are considered in developing the thermodynamic model. Two methods for solving the governing equations are proposed. The model is used to predict the power output, and the thermal efficiency. The proposed model is validated against experimental data available from the General Motor GPU-3 Stirling engine prototype. Parametric study is used to investigate the effect of geometric and operation parameters on the engine performance. The effect of regenerator effectiveness, the dead volume ratio, regenerator thermal conductivity, and the heat source temperature, the swept volume ratio on the maximum on engine performance are evaluated. It is found that significant improvement on engine performance can be achieved by optimizing geometric and operating parameters.
  • Combined heat loss analysis of trapezoidal shaped solar cooker cavity
           using computational approach

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Jayashree Nayak, Mohit Agrawal, Saumyakanta Mishra, Sudhansu S. Sahoo, Ranjan K. Swain, Antaryami Mishra The present paper focuses on computational approach to analyze the heat loss due to natural convection and radiation in a trapezoidal shaped solar cooker. Heat losses due to forced convection and radiation are considered from the top glass cover. The results are verified with standard procedure. Radiative heat loss from the cavity is found to be dominant mode which contributes around 70–80% of the total heat loss. Parametric studies regarding heat loss from the cavity are studied by varying cavity depths, heat transfer coefficients based on the wind speed above the glass surface, emissivity of the plate. Based on different parameters, flow pattern and isotherms inside the cavity have been analyzed. Results are obtained in non-dimensional forms for more generic use and correlation between the total average Nusselt number and its influencing parameters has been formulated for the considered solar cooker cavity.
  • Forecasting the heating and cooling load of residential buildings by using
           a learning algorithm “gradient descent”, Morocco

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Alaoui Sosse Jihad, Mohamed Tahiri In this study, the main objective is to predict the energy needs of residential buildings in the climate zone of Agadir, Morocco, benefitting from orientation, relative compactness, glazing rate, wall surface area, the height and the surface area of the building by using artificial neural networks (ANN) as a learning algorithm. The training data of the neural network were produced using parametric analysis giving rise to 5625 samples in accordance with the mode of construction and use of residential buildings. For each building, it is assumed that the angles of orientation of the samples vary from 0° to 180°, the glazing rates were chosen between 5% and 45%, the heights between 3.5 and 17.5 m and with 25 possible building areas. Three residential buildings "Economic Villa, Economical Construction and Medium Class building" were selected as test data for the neural network model. The Design Builder tool was used for energy demand calculations and a computer program written in Python is used for predictions. As a conclusion; When comparing the calculated values with the outputs of the network, it is proved that the ANN gives satisfactory results with an accuracy of 98.7% and 97.6% for the prediction and test data respectively.
  • Experimental and theoretical research on the fire safety of a building
           insulation material via the ignition process study

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Yufeng Huang, Yufeng Li A series of experiments were carried out on extruded polystyrene (XPS) foam using a vertical thermal radiator. Measurements were taken for the ignition time, the pyrolysis mass and the temperature distribution. Two kinds of XPS foam with flame retardant levels of B1 and B2 were tested in the experiments and the incident heat fluxes were set as 20, 30, 35, 40, 50 and 60 kW/m2. For the XPS shrinks to a thin layer under the thermal radiator heating, thus the classical ignition theory may be improper and the new functions relationship between the ignition time and the radiant heat flux was derived in theory and experiment. What's more, the pyrolysis mass increases with the radiant heat flux, while the extent of increasing reduces as the radiant heat flux increases. And the result of temperature distribution indicated that under high incident heat flux the flame retardant treatment becomes less effective. The research results were useful for the theory and the experimental study on the fire characteristic of foamed polymer under vertical radiation condition.
  • Experimental study on smoke temperature distribution under different power
           conditions in utility tunnel

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Yong-chang Zhao, Guo-qing Zhu, Yun-ji Gao The longitudinal and cross-sectional temperature distributions are measured in reduced-scale tunnel fire experiments with different fire power conditions. Field tests are carried out in a utility tunnel with pool fires. The experiments studied the ceiling temperature along the tunnel centerline, the vertical temperature below the ceiling and the temperature in the direction of radian in the same section with the fire source. The results from the burning experiments are analyzed. The longitudinal temperature distribution along the tunnel can be fairly well fitted by exponential equations. And the thermal radiation of the smoke layer has a significant effect on the temperature below the ceiling. In addition, in the direction of tunnel radian, the temperature growth rate of the region above 45° are obviously faster and the temperature is higher. Therefore, to shorten the response time of the detector to the fire, it is desirable to place the heat and smoke detectors at the top of the utility tunnel.
  • Case study on thermal impact of novel corrosion inhibitor on mild steel

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Hussein Jwad Habeeb, Hasan Mohammed Luaibi, Thamer Adnan Abdullah, Rifaat Mohammed Dakhil, Abdul Amir H. Kadhum, Ahmed A. Al-Amiery Just a few investigations have studied the function of various temperatures in distribution system mild steel corrosion. Generally, increasing temperatures caused the accelerated corrosion of mild steel. In addition, the average of chemical processes were increased as the temperatures were increased regarding to Arrhenius' Law. The synthesis and characterization of a novel organic corrosion inhibitor 4-(((5-ethyl-1,3,4-thiadiazol-2-yl) imino) methyl) phenol, for mild steel in hydrochloric acid was successfully reported for the first time. This inhibitor is tested as corrosion inhibitor on a mild steel sample MS in 1 M hydrochloric acid solution using Potentio-dynamics (PD) and Electrochemical Frequency Modulation (EFM) method. The results obtained indicate that inhibitor acts as an excellent corrosion inhibitor for mild steel sample in HCl solution with efficiency above 90%. Changes in the results parameters suggested adsorption on the surface of mild steel sample, which it leading to the formation of protective coating layer. However, this protective layer becomes weak when the temperature of the solution increases.
  • Exhaust noise, performance and emission characteristics of spark ignition
           engine fuelled with pure gasoline and hydrous ethanol gasoline blends

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Xiaokang Deng, Zhenbin Chen, Xiaochen Wang, Haisheng Zhen, Rongfu Xie The exhaust noise, performance and emission characteristics of a gasoline engine fuelled by hydrous ethanol gasoline with 10%, 20% hydrous ethanol by volume (E10W and E20W) and pure gasoline (E0) were experimentally investigated. The tests were performed at full load and different engine speeds varying from 1500 rpm to 5000 rpm. The results showed that compared with E0, E10W and E20W had much lower exhaust noise at low engine speeds. With the increase of engine speed, E0 showed an advantage in low exhaust noise. However, engine fuelled with three fuels displayed comparable noise emissions at high speed. In addition, better thermal efficiency, significantly decreased CO and HC emissions were achieved by hydrous ethanol gasoline at all tested operating conditions. However, significant NOx emission and slight BSFC were observed for E10W and E20W. Compared with E20W, E10W showed decreased BSFC, HC and NOx emissions with the increase of engine speed, while CO emission was only slightly increased. Hydrous ethanol gasoline was capable of realizing comparable torque and power with E0 at all operating conditions. From the results above, hydrous ethanol gasoline could be considered as a promising alternative for SI engine. What's more, E10W exhibits enhanced performance.
  • Influence of mechanical smoke exhaust on smoke spread in underground

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Hai jun Tao, Guoqing Zhu, Yu Xia, Yongchang Zhao The model of a tunnel in Beijing is established, and the smoke reflux, the smoke reflux length and the influence of longitudinal wind speed on temperature distribution of the tunnel vault are studied using numerical simulation method. The length of the tunnel is 150 m, the cross section is circular, the height of the tunnel is 6.3 m and the width is 6 m. The simulation results show that the smoke reflux length of the subway tunnel fire decreases with the increase of the longitudinal positive pressure wind speed, and the reflux length decreases linearly with the increase of wind speed when the reflux length is more than 10 m. The gradient of the reflux length decreases with the increase of the wind speed when the distance from the fire source decreases. The temperature curve of tunnel vault is consistent. Under the same fire source heat release rate, the flue gas temperature decreases with the increase of ventilation wind speed, and the distance between the highest temperature of the ceiling and the fire source decreased with the increase of the longitudinal ventilation wind speed.
  • On the conceptual design of the novel balanced rolling piston expander

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Antonio Giuffrida, Gianluca Valenti, Davide Palamini, Luigi Solazzi This work presents a novel type of positive-displacement expander, named the balanced rolling piston expander. It proposes also a design procedure and assesses the mechanical behavior of a virtual prototype. The expander is conceptually capable of operating at higher fluid temperatures than other positive-displacement expanders, such as scroll- or screw-type machines. Moreover, it employs a radially balanced rotor, differently from common rolling piston technologies and does not require any timing mechanism for filling and emptying the working chambers, differently from Wankel or reciprocating solutions. The investigated virtual prototype is chosen for the study case of a small-scale heat recovery unit currently under investigation. The results indicate that a prototype of about 300 mm in diameter and 100 mm in length is capable of an ideal power of 20 kW. Moreover, vane accelerations can be relatively high but anyhow comparable to those in sliding vane machines, while pressure drops in percent terms are in general lower than 1%. Lastly, load-induced displacements are manageable by a proper radial clearance at room temperature. In brief, the balanced rolling piston expander is a promising option for small-scale power generation units operating with temperatures not achievable by common technologies and, hence, it deserves further investigation.
  • An integrated program of a stand-alone parabolic trough solar thermal
           power plant: Code description and test

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Sanan T. Mohammad, Hussain H. Al-Kayiem, Morteza K. Assadi, Osama. Sabir, Ayad K. Khlief Solar thermal systems produce steam after being energized by solar parabolic trough concentrators, are incorporated with a steam turbine-generator assembly to produce electricity. This study presents a code for prediction of performance, while under-taking preliminary plant-sizing for a variety of parabolic trough solar fields operating under nominal conditions. The code, named as PTPPPP (Parabolic Trough Power Plant Performance Predictor) consists of four blocks. The code allows prediction of variables including: heat loss coefficient, UL, aperture effective direct normal irradiance, I, heat gain, Qgain, and the thermal efficiency of stand-alone parabolic trough solar thermal power plant in commerce, ηp. The conceptual design of the stand-alone parabolic trough solar involves: selection and sizing of system components, power generation cycles, working fluid types, and power block sizing. The input weather parameters and the operational parameters to the code have been acquired from in-situ measurements. The prediction results of the code have been found in good agreement with literature data with mean error of 0.18% in prediction of output power. In addition, this code is able to provide a flexibility in terms of temperature, heat transfer, and pressure range.Graphical abstractA solar thermal power plant model, based on parabolic trough concentrators has been proposed as above. The plant has been modelled mathematically and in-site weather measured data have been input to the model to assist in sizing and analysis of the process parameters.fx1
  • Carreau fluid flow in a thermally stratified medium with heat
           generation/absorption effects

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Khalil Ur Rehman, Ali Saleh Alshomrani, M.Y. Malik In this article theoretical attempt is carried to inspect the flow field characteristics of Carreau fluid model. The fluid flow is achieved by stretching cylindrical surface with no slip condition that is the relative velocity of Carreau fluid particles and cylindrical surface is zero. The role of both temperature stratification and heat generation/absorption are considered with the source of energy equation. The physical illustration of flow model with both temperature stratification and heat generation/absorption effects is translated in terms of partial differential equations through fundamental laws, namely law of conservation of mass, momentum and energy. The obtained partial differential equations are non-linear in nature and it seems difficult to solve them analytically. Therefore the boundary layer approximation is utilized to retain the active parts of flow narrating differential equations. Then to step down the partial differential equations in terms of ordinary differential equations a set of transformations is introduced. The reduced system is solved by shooting method and self-coded algorithm is executed in this regard. The note down observations are offered with the aid of graphs and tables. It is noticed that the Carreau fluid temperature shows decline nature towards the positive values of thermal stratification parameter and heat absorption parameter but it reflects opposite trend for the case of heat generation parameter.
  • Studies on energy consumption of crude oil pipeline transportation process
           based on the unavoidable exergy loss rate

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Qinglin Cheng, Anbo Zheng, Lu Yang, Chenlin Pan, Wei Sun, Yang Liu In order to ensure the crude oil pipeline process smoothly, the driving force has a certain exergy loss. Based on the exergy analysis method, according to the required minimum potential difference of pipeline transportation, the unavoidable exergy loss is defined in the process. In order to reflect the real effective utilization degree of energy consumption, the unavoidable exergy loss rate is put forward as the evaluation index. And it is calculated by the ratio of related the unavoidable exergy loss and the exergy loss. The crude oil pipeline exergy loss rate is calculated under different conditions. The orthogonal experiment analysis used to compare the influence degree of different operating parameters on the pipeline unavoidable exergy loss rate show that the influence degree on the unavoidable exergy loss rate in turn is: outbound temperature, flow and outbound pressure. It also provide the reference for the energy-saving transportation of crude oil pipeline.
  • Some solar passive concepts in habitat through natural ventilation case
           study: Dry climate in Algeria Ghardaia

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): M.K. Cherier, T. Benouaz, S.M.A. Bekkouche, M. Hamdani The main objective of this paper is to study the effect of one of the most important negative concepts through natural ventilation as an economical solution and an inexpensive health phenomenon. Ventilation of buildings is a commitment and requires a minimum of flue that must be guaranteed to avoid discomfort. Air leakage in heated space increased incoming flow rates. Therefore, the leakage in the envelope building plays a major role in thermal losses. Loss created by air exchange system. So experts stressed that opening and closing windows provides a way to control the outside air in all cases. Through the daily programming schedule by climate and region, for example Ghardaia. The area of Ghardaia features characteristics of a high temperature zone especially for the months May to October. This period is characterized by climate and is often hot and in our case with habitat to strong thermal inertia of it can generate discomfort. In this case the thermal inertia is not suitable. Therefore, no other solution of ventilation night becomes more important in hot weather.
  • Numerical Investigation of heat transfers in the water jacket of heavy
           duty diesel engine by considering boiling phenomenon

    • Abstract: Publication date: Available online 10 July 2018Source: Case Studies in Thermal EngineeringAuthor(s): M. Gholinia, M. Pourfallah, H.R. Chamani The flow of the coolant fluid and its heat transfer directly affect the cooling performance, heat load of the hot parts and also the thermal efficiency of the diesel engine. The proper estimation of heat transfer and temperature distribution in a diesel engine is essential for investigating the thermal stresses and calculating its performance, which requires a precise simulation of the cooling water jacket. An efficient approach to study the cooling system is to simulate using Computational Fluid Dynamics (CFD) as a three-dimensional model by simultaneously solving the structure and fluid, which leads to accurate prediction of wall temperature and heat flux. In the present paper, the distribution of heat transfer coefficients (HTC) in the cooling jacket of a 16-cylinder heavy-duty diesel engine has been calculated using ANSYS/Fluent based on 3D-CFD method. Also, equations of subcooled boiling phenomenon have been solved based on methods of Chen and BDL, and the effects of fluid pressure, velocity, and temperature (At the time of the phenomenon of boiling) on the heat transfer of cooling jacket wall have been studied. The results show that the sensitive thermal region that is at risk is the region between the exhaust valve and around the glow-plug. This region if not properly cooled, will result in gas leakage from the combustion chamber, which will result in a decrease in engine power and torque.
  • Actual validation of energy simulation and investigation of energy
           management strategies (Case Study: An office building in Semnan, Iran)

    • Abstract: Publication date: Available online 30 June 2018Source: Case Studies in Thermal EngineeringAuthor(s): Afshin Fathalian, Hadi Kargersharifabad Due to the wide range of parameters effect in energy consumption within a building, it is not possible to make a proper decision about the impact of different energy efficiency strategies without simulation tools. In this study, the annual energy consumption of an office building in Semnan, Iran is simulated using DesignBuilder software. The validation of simulation results is down by monthly electricity and natural gas energy consumption billing records with the highest simulation error of about 1.6%. Three strategies are proposed to management the energy consumption, e.g. the replacement of single-glazed windows with low-emission double-glazed window, installation of a thermal insulation sheet on the external wall of the building and use of horizontal shadings on the outside and removal of the internal shades. The simulation results show that these strategies lead to 14%, 18% and 13% reduction in energy consumption, respectively. In order to revalidate the simulation, the strategy of replacing the existing windows with low-emission double-glazed is adopted and the actual energy consumption of the building is compared with the simulated value after one year, indicating a good agreement at this stage.
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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Fax: +00 44 (0)131 4513327
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