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  Subjects -> ENGINEERING (Total: 2526 journals)
    - CHEMICAL ENGINEERING (212 journals)
    - CIVIL ENGINEERING (219 journals)
    - ELECTRICAL ENGINEERING (121 journals)
    - ENGINEERING (1326 journals)
    - ENGINEERING MECHANICS AND MATERIALS (403 journals)
    - HYDRAULIC ENGINEERING (57 journals)
    - INDUSTRIAL ENGINEERING (85 journals)
    - MECHANICAL ENGINEERING (103 journals)

ENGINEERING (1326 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: 21)
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: 7)
ACS Nano     Hybrid Journal   (Followers: 319)
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: 6)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 10)
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: 24)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 23)
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: 51)
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: 12)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 25)
Anadolu University Journal of Science and Technology A : Applied Sciences and Engineering     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 4)
Annals of Pure and Applied Logic     Open Access   (Followers: 3)
Annals of Regional Science     Hybrid Journal   (Followers: 8)
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: 7)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 20)
Applied Clay Science     Hybrid Journal   (Followers: 6)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 14)
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: 4)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 7)
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: 6)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 9)
Arid Zone Journal of Engineering, Technology and Environment     Open Access   (Followers: 2)
Arkiv för Matematik     Hybrid Journal   (Followers: 2)
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: 2)
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 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  
AURUM : Mühendislik Sistemleri ve Mimarlık Dergisi = Aurum Journal of Engineering Systems and Architecture     Open Access  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autocracy : Jurnal Otomasi, Kendali, dan Aplikasi Industri     Open Access  
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: 2)
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: 12)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering     Hybrid Journal   (Followers: 2)
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: 19)
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: 40)
Bitlis Eren University Journal of Science and Technology     Open Access  
Black Sea Journal of Engineering and Science     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: 32)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 44)
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: 8)
Catalysis Science and Technology     Hybrid Journal   (Followers: 9)
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: 23)
Clean Air Journal     Full-text available via subscription   (Followers: 1)
Clinical Science     Hybrid Journal   (Followers: 8)
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: 3)
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 Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering     Open Access  
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: 29)
Composite Interfaces     Hybrid Journal   (Followers: 7)
Composite Structures     Hybrid Journal   (Followers: 295)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 233)
Composites Part B : Engineering     Hybrid Journal   (Followers: 272)
Composites Science and Technology     Hybrid Journal   (Followers: 205)
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)

        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  [3161 journals]
  • Heat transfer simulation and thermal efficiency analysis of new vertical
           heating furnace

    • Abstract: Publication date: Available online 15 February 2019Source: Case Studies in Thermal EngineeringAuthor(s): Wang Chunsheng, Zhou Yan, Yang Fuxiang, Liang Zejun In view of the unclear heat transfer characteristics of the new type natural ventilation heating furnace designed by Liaohe Oilfield, the simulation combined calculation method is adopted. The heat transfer capacity of different components is analyzed through the flue gas temperature drop. The thermal efficiency is calculated by the positive and negative balance method combined the simulation results, and the efficiency under the different inlet temperature, the inlet flow rate and the flow rate of crude is analyzed and calculated. The results show that the designed heating furnace efficiency is over 90%, which is nearly 7% higher than that of the old heating furnace. The heat transfer effect of different components is different. The horizontal smoke pipe makes the temperature drop effect of the flue gas the most obvious, and the temperature drop can be achieved. 313 °C, is an important heat transfer component in the furnace. At the same time, no heat collection at the top of the furnace is found. Among the factors affecting the thermal efficiency, the amount of crude oil processed by the heating furnace has the greatest influence on the thermal efficiency, which can cause the efficiency fluctuation to reach 12%.
       
  • Numerical study of MHD effective Prandtl number boundary layer flow of γ
           Al 2 O 3 nanofluids past a melting surface

    • Abstract: Publication date: Available online 12 February 2019Source: Case Studies in Thermal EngineeringAuthor(s): N. Vishnu Ganesh, Qasem M. Al-Mdallal, P.K. Kameswaran This research article numerically study the influences of an effective Prandtl number along with magnetic field on the melting heat transport characteristics of Ethylene glycol/Water with gamma Al2O3 nanoparticles over a stretching sheet. To analyse the impacts of effective Prandtl number, the non-dimensional melting heat transfer boundary conditions are derived for the first time with and without effective Prandtl number. A non-linear form of thermal radiation is used. The experimental based thermo-physical properties of gamma Al2O3 nanofluids are considered. The electric conductivities of Al2O3, water and ethylene glycol are used to calculate of effective electric conductivity to study the magnetic field effects. Mathematical models are developed and solved by numerical technique based on the Iterative Power Series (IPS) method with shooting strategy. The numerical outcomes are discussed through plots and tables.
       
  • Thermal performance analysis of net zero energy home for sub zero
           temperature areas

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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.
       
  • Numerical optimization on thermal performance characteristics of interior
           walls based on air-conditioning intermittent running

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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.
       
  • Architectural design of Residential Buildings in Qinba Mountains based on
           knowledge mapping

    • Abstract: Publication date: Available online 7 February 2019Source: Case Studies in Thermal EngineeringAuthor(s): Lin Zhao, Juan Xu This article has selected knowledge mapping as the research method and China HowNet as the references source, 222 related research papers are selected to analyze and summarize the keyword co-occurrence network, aiming at the problems of residential architecture research in Qinba Mountains. For the clustered hotspots, taking the traditional residential buildings in Qinba Mountains as an example, this paper carries out a survey and summarizes the ways of residential design in Qinba Mountains, with a view to providing a better reference for the design of residential buildings in this area.
       
  • Experimental thermal characterisation of an ironless inductive position
           sensor

    • Abstract: Publication date: Available online 6 February 2019Source: Case Studies in Thermal EngineeringAuthor(s): Adrian Grima, Alessandro Masi, Mario Di Castro, Nicholas Sammut This article reports an experimental study performed on the ironless inductive position sensor to understand the relationship between changes in the surrounding temperature and position reading of the novel linear position sensor. The measured variation of the basic electrical components with temperature is presented and shows that the position drift of the sensor varies with the state of the sensor. The states include the moving coil position, and the frequency of operation. The results also reveal that the resistance and inductance changes happen in all the coils. Furthermore, the results show that when subjected to an even temperature change, the moving coil contributes to the highest change. In addition, uneven thermal distribution along the body of the sensor leads to high sensitivity from the sense coils. The results also indicate that the inductance change is small and leads to a small position change.
       
  • Modelling surface temperature of granite seawalls in Singapore

    • Abstract: Publication date: Available online 4 February 2019Source: Case Studies in Thermal EngineeringAuthor(s): Kuifeng Zhao, Jing Yuan, Lynette H.L. Loke, Shelley H.M. Chan, Peter Alan Todd, Philip Li-Fan Liu Temperature is a critical abiotic factor structuring intertidal life on hard-bottom habitats, including manmade coastal defense structures. To quantitatively describe the daily surface temperature variations of a seawall in Singapore, a physically based mathematical model is developed, which considers key thermal processes (i.e., solar radiation absorption, long wave emission, and heat convection). This model is nonlinear because of the nonlinear boundary conditions and the moving seawater level boundary. It is therefore solved numerically with appropriate initial conditions. Good model - data comparison is confirmed with field measurements. Results show that the maximum seawall temperature reached as high as about 48 C∘. Temperature variation was illustrated using contour plots. A high temperature index on the seawall, T95%, is defined as the threshold temperature that 95% of all temperatures at a given elevation do not exceed. T95% will be useful for investigating the effects of temperature on biodiversity in intertidal systems. The effect of seawall slopes and monsoons on T95% is further examined. For Singapore’s seawalls, it is found that the extreme temperature decreases with increasing slope, and the T95% during the southwest monsoon season is approximately 4 C∘ higher than that during the northeast monsoon.
       
  • Entropy generation in MHD radiative viscous nanofluid flow over a porous
           wedge using the bivariate spectral quasi-linearization method

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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, thermophoresis 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.
       
  • Analysis of activation energy in magnetohydrodynamic flow with chemical
           reaction and second order momentum slip model

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Aaqib Majeed, F.M. Noori, A. Zeeshan, T. Mahmood, S.U. Rehman, 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.
       
  • Effect of diffuse solar radiation on the thermal performance of solar
           collectors

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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.
       
  • Cooling performance of Al2O3-water nanofluid flow in a minichannel with
           thermal buoyancy and wall conduction effects

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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.
       
  • Numerical study on air ventilation in the workshop room with multiple heat
           sources

    • Abstract: Publication date: Available online 1 February 2019Source: Case Studies in Thermal EngineeringAuthor(s): Songkran Wiriyasart, Paisarn Naphon In the present study, the application of computational fluid dynamic (CFD) to analyze air quality and thermal distribution in the workshop room with the multiple heat sources are investigated. In numerical study, a three-dimensional of a single-phase turbulent flow model is employed to analyze temperature distribution and fluid flow in workshop room. The initial and boundary conditions of the models are based on the experimental data. By solving the equations of continuity, momentum, and energy, the velocity and temperature distributions of air within workshop room are presented. It was found that the predicted air temperature and air velocity within the workshop room are consistent with the experimental results. The ventilation system positions and the installed position of equipment inside the workshop have significant effect on suction force which results in the accumulated heat and transport air pollution within the workshop room. The obtained results of the study are expected to lead to guidelines that will allow the designing the ventilation of air-cooling system to transport air pollution and accumulated heat for large workshop room coupled with multiple heat sources.
       
  • Cycle improvement and hydrogen steam superheating at Mutnovsky geothermal
           power plant

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): D.O. 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%.
       
  • Extraction of bio-oil during pyrolysis of locally sourced palm kernel
           shells: Effect of process parameters

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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 °C and 550 °C and particles sizes of 1.18 mm, 2.36 mm and 5 mm for a residence time not greater than 120 min. The maximum bio-oil yield was 38.67 wt% at 450 °C for a feed particle size of 1.18 mm with a residence time of 95 min. 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 °C. 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 min. As observed, the optimum residence time was 95 min 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.
       
  • Control of electric power generation of thermal power plant in TamilNadu

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): M.S. Murshitha Shajahan, D. Najumnissa Jamal, V. Aparna, 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.
       
  • Performance, energy loss, and degradation prediction of roof-integrated
           crystalline solar PV system installed in Northern India

    • Abstract: Publication date: Available online 1 February 2019Source: Case Studies in Thermal EngineeringAuthor(s): Nallapaneni Manoj Kumar, Ramjee Prasad Gupta, Mobi Mathew, Arunkumar Jayakumar, Neeraj Kumar Singh This article predicts the performance, energy loss, and degradation of a 200 kW roof-integrated crystalline photovoltaic (PV) system installed at IRB Complex-5, Chandigarh in the Northern part of India. PVsyst simulation tool is used for predicting the energy generation, and energy loss. Analysis of the energy generation and various input parameters are carried out for evaluating the capacity factor (CF), performance ratio (PR), and efficiencies. For a detailed analysis of the energy losses, a three-stage approach (sunlight reaching onto the PV array, sunlight into DC electricity conversion, and DC to AC electricity conversion) is used. The light-induced degradation (LID), which is possible in the PV modules in the second stage (sunlight into DC electricity conversion) is predicted using the PVsyst simulation modeling. Apart from this, the possible degradation rate (DR) in the crystalline PV systems is considered based on the All-India survey of PV module reliability reports. The predicted results show that 292954 kWh of energy generation is possible on an annual basis from the planned PV system. The system is estimated to operate with a yearly CF, PR, and energy losses as 16.72%, 77.27%, and -26.5% respectively. The estimated DR of the PV system would lie between 5%/year, and the possible LID is 2.5%/year. Finally, the energy losses due to LID, and DR are predicted as 8109.99 kWh/year, and 14647.7 kWh/year respectively.
       
  • Techno-economic assessment of corn stover for hybrid bioenergy production:
           A sustainable approach

    • Abstract: Publication date: Available online 1 February 2019Source: Case Studies in Thermal EngineeringAuthor(s): Subhash Paul, Animesh Dutta, Mahendra Thimmanagari, Fantahun Defersha Corn stover (CS) contains high moisture in the fall and farmers keep it unharvested until next spring for its natural drying. CS contains 70% more carbon than other grain crop residues. Farmers traditionally use a portion of CS for livestock bedding and cattle feed but the rest is kept unharvested. Potential soil erosion, carbon sequestration, and nutrient removal concerns might be considered before CS harvesting. Hydrothermal carbonization (HTC) of wet biomass can produce energy dense solid bio-carbon. Hydrothermal process water (HTPW) can produce energy and recover nutrient in anaerobic digestion (AD). This study reported the results of various experiments performed on non-rooted fall harvested CS of an Ontario farm. Ontario CS was finally assessed for techno-economic and environmental aspects. This research showed 78% energy and a portion on nutrients as liquid bio-fertilizer of fall harvested CS are recoverable. Corn roots with 6–10 cm stalks, cobs and husks can be kept in the soil to recover soil organic matter (SOM) and protection of soil erosion. The process indicates the sustainable CS harvesting in the fall with possibility to reduce 75% of existing harvesting cost and reduction of greenhouse gas (GHG) emission.
       
  • Combined effect of pulsating flow and magnetic field on thermoelectric
           cooler performance

    • Abstract: Publication date: Available online 31 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): M.S. Nassar, A.A. Hegazi, M.G. Mousa The performance enhancement of the thermoelectric cooler (TEC) by controlling the working conditions is the main target of the present experimental investigation. The present study handles the variation of the most effective parameters through changing the pulsating air flow by introducing cases of Womersley number (Wo); 0 ≤ Wo ≤ 41.28. The magnetic field intensities Bo; 0.875 ≤ Bo ≤ 1.25 T, at different input current (I) from 4.6 to 7.4 Amp, at 0.0542 kg/s mass flow rate. The test section consists of a set of four TEC integrated with eight heat sinks, exposed to a magnetic field emitter, and two DC motors to create pulsating flow, all enclosed in a rectangular duct. The maximum obtained coefficient of performance (COP) in case of pulsating flow was 0.24. While at the case of both magnetic field and pulsating flow was 0.277. Comparing with the case of TEC without both effects it was 0.192. Comparing with previous works the results shows a good trend agreement.
       
  • Numerical investigation on fire-extinguishing performance using pulsed
           water mist in open and confined spaces

    • Abstract: Publication date: Available online 31 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Zhun Lin, Rongwei Bu, Jiaming Zhao, Yang Zhou The objective of this study is to bring basic information on the fire extinguishing mechanism in a pulsed water mist system using the method of Large Eddy Simulation (LES). The fire extinguishing performances with continuous and pulsing discharge modes were numerically investigated by measuring smoke temperature, oxygen concentration and fire-extinguishing time. The results found that the pulsed water mist has no obvious advantage over the continuous water mist in the open space, but has a considerable extinguishment performance by optimizing the interval of the pulsing discharge mode in the confined space. The optimum pulse interval was obtained. Moreover, the oxygen dilution effect of pulsed water mist plays an important role in fire extinguishment. The numerical simulations conducted in this work can provide global information on the fire-extinguishing time under different discharge modes as well as spatially-resolved information on the advantages of pulsed water mist extinguishment based on oxygen concentration and water vapor concentration. The results suggested that the best suppression performance of the pulsed water mist was achieved when the oxygen concentration around the flame base was diluted. The above results can provide a significant reference for the optimal design of water mist system.
       
  • Net-zero building designs in hot and humid climates: A state-of-art

    • Abstract: Publication date: Available online 31 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): K. Sudhakar, Maximilian Winderla, S. Shanmuga Priya Net Zero building is becoming a global trend as a strategy to reduce the carbon footprint. In order to achieve Net-Zero building design in hot and humid climates, efforts must be put to reduce the overall energy use to the maximum extent by integrating appropriate building technologies into the architectural designs. In this paper, the latest ideas dealing with building performances and net-zero building design projects, are reviewed and an outlook is given including new concepts of combined systems in hot and humid climate regions. The paper is structured in the following manner which includes basic guidelines, natural ventilation systems, cooling and dehumidification, insulation and construction materials, reviews of several net-zero energy building projects. The paper also proposes novel wind tower dehumidification design and ventilated attic building design for the hot and humid region. Thus the state of art review is presented for net-zero buildings in a hot and humid climate.
       
  • Phase-change heat transfer analysis of shutdown overhead pipeline

    • Abstract: Publication date: Available online 31 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Xu Ying, Nie Xin, Cheng Qinglin, Dai Zhonghua, Liu Xiaoyan, Liu Yang, L.I. Cong according to the characteristics of waxy crystal phase change during waxing process of crude oil, a novel model that was a wide phase transition interface partition model was established, and the equivalent specific heat capacity method was used to deal with latent heat problem. The governing equations for each partition were proposed. Compared with the experimental data, the maximum relative error was 3.41%, and then the model was used to analyze the heat transfer process of oil phase change. The research results can provide important theoretical support for the practical application of overhead pipeline shutdown and maintenance.
       
  • Analysis of working parameters for an ammonia-water absorption
           refrigeration system powered by automotive exhaust gas

    • Abstract: Publication date: Available online 31 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Sérgio Hanriot, Pedro Brito, Cristiana Maia, Attenister Rêgo In the present work, an experimental investigation was performed to determine effective working parameters for an ammonia-water absorption refrigeration system powered by waste heat from the exhaust gases of a vehicular internal combustion engine. The automotive exhaust system was connected to the generator of a commercial absorption refrigerator originally intended to operate with the heat generated from an LPG burner. In an attempt to increase performance, a close-looped exhaust gas flow control system was designed and implemented that allowed the generator temperature to be maintained at pre-determined values. Thus, a series of tests were performed with varying generator temperatures (180, 200, 240, and 270 °C) while monitoring engine torque, speed, and temperature at different points of the system. Using this methodology, it was found that the system is significantly sensitive to generator temperatures, and satisfactory performance was only noted for the set value of 200 °C. Under this operating condition, after 240 min test runs, minimum temperatures of −12.5 and −0.6 °C were obtained, respectively, at the evaporator element and interior of the absorption refrigerator, while the maximum coefficient of performance (COP) registered was almost 0.05.
       
  • Numerical study on the effects of opening form on the deflation for an
           air-supported membrane structure

    • Abstract: Publication date: Available online 30 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Jinju Zhou, Guoqing Zhu, Yunji Gao, Shuai Gao, Guoqiang Chai Air-supported membrane structure has been widely applied to large-span space due to its advantages of light weight, low cost, reusability. The static load bearing capacity and the dynamic deployment simulation of air-supported membrane structure have received extensive attention. However, very few studies have been reported to investigate its deflation behavior. Although several dynamic finite element algorithms can be applied to the deflation simulation, their computational costs are large. The concept of critical pressure point was introduced in this paper, by which the deflation process was divided into two stages of decompression and collapse. A series of numerical simulations were performed to study the effects of opening area and position on the pressure change in decompression process for air-supported membrane structure. The study showed that the required time for the critical pressure point reached initially decreases sharply gradually evolving into a slight decrease as the opening area increases from 0.5 to 6 m2, which followed a power equation as a function of opening area. Moreover, for a fixed opening area, opening position at top exhibits a minimum value followed by middle position, while a maximum value is shown when the opening is at bottom position. It is obviously that the decompression phase is affected significantly by the opening area and position. The above results have a certain meaning for safety assessment of personal evacuation under emergency deflation of the air-supported membrane structure.
       
  • Planned production of thermal units for reducing the emissions and costs
           using the improved NSGA II method

    • Abstract: Publication date: Available online 29 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Mehdi Neyestani, Sadegh Hesari, Mohammad Hatami This paper presents a new algorithm for production planning, thermal units called so-called economic dispatch. The selected problem for algorithm implementation is a bounded and non-linear optimization problem. In the present paper, it has been tried to reduce the production costs, as well as the polluting gases emitted while generating energy. The proposed algorithm is based on multi-objective optimization algorithm of Genetic Algorithm, which is a meta-heuristic algorithm. In this paper, an idea is suggested to improve the efficiency of the multi-objective optimization algorithm. After implementation and comparing the results obtained for the multi-objective standard algorithm with the previous works, it was observed that the proposed algorithm can obtain better results. To investigate the results, a 3-generator system with and without considering the losses was used. However, in each state, 3 different demands for energy was considered and the algorithm was implemented on this system. The proposed algorithm, find answers with less than 0.15% improvement in production costs, as well as on average 0.30% improvement on the find answers with less contaminant.
       
  • Evaluation and analysis of water-based photovoltaic/thermal (PV/T) system

    • Abstract: Publication date: Available online 28 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Hussein A. Kazem Water-based PV/T collectors are useful for simultaneous hot water and electricity generation. This paper presents the design of a grid-connected water-based PV/T and performance evaluation from outdoor experiments in weather conditions of Oman. The paper focuses on the electrical performance of the system under three days of testing and draws conclusions onto the effect of ambient conditions and solar irradiance on conventional PV panels and PV/T collectors. The proposed PV/T shows superior electrical performance during the examination period, with consistent rise in electrical efficiency over conventional PV. The peak electrical power and voltage achieved by the system are around 67 Wp and 18.9V, respectively. The average power of the PV/T panel is 6% higher than average power of conventional PV panel.
       
  • 3-D numerical investigation on commercial PTFE membranes for membrane
           distillation: Effect of inlet conditions on heat and mass transfer

    • Abstract: Publication date: Available online 28 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Mohamed S. Salem, Ahmed H. El-shazly, Norhan Nady, Mohamed R. Elmarghany, Mahmoud A. Shouman, Mohamed Nabil Sabry Computational fluid dynamics (CFD) techniques were implemented to develop a 3-D numerical model to investigate the effect of several inlet conditions on the heat and mass transfer through a commercial PTFE membrane in a specific direct contact membrane distillation (DCMD) cell design. The model was validated against other researchers’ results and was found to have a good arrangement. The model was then used to predict the effects of changing the direction of the flow, inlet Reynolds number and feed inlet temperature on the permeate flux through the membrane and the process thermal efficiency. It has been found that changing the flow arrangement from parallel to counter flow slightly increased the permeate flux. Changing the inlet Reynolds number from 25 to 50 significantly increased the permeate flux and the process thermal efficiency, while raising it from 50 to 150 had little to no effect. It has also been found that increasing the feed inlet temperature from 303 K to 323 K almost tripled the permeate flux.
       
  • Hybrid nanofluid to enhance heat transfer under turbulent flow in a flat
           tube

    • Abstract: Publication date: Available online 28 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Sheren A. Kaska, Rafeq A. Khalefa, Adnan M. Hussein The heat transfer enhancement by utilizing hybrid nanofluid is a new class of heat transfer enhancement. In this paper, CFD model with commercial software adopting the finite volume method and SIMPLE algorithm has been conducted. Mixture of Aluminum Nitride (AlN) and alumina (Al2O3) nanoparticles into water as a base fluid is considered as a new concept of hybrid nanofluid for enhancing heat transfer. It was performed the simulation procedures with the volume fraction (1, 2, 3 and 4%) and Reynolds number are changing from 5000 to 17000. The heat flux applied along the elliptical tube is 7000 w/m2 and the nanoparticles size diameter is fixed at 35 nm. The validation of computational results has been performed with experimental data available in the literature. The results indicated that the hybrid nanoparticles of AlN - Al2O3 suspended in water as a base fluid tends to enhance heat transfer significantly.
       
  • Average view factors for extended surfaces with fractal perforations

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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.
       
  • Magnetoresistance of Cryogenic Linear Temperature Sensor

    • Abstract: Publication date: Available online 15 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Qiumin Meng, Zhengrong Ouyang, Shuai Zhang, Junjie Li, Hongqiang Li, Lei Shi, Ming Fang The 40 T hybrid magnet was developed at High Magnetic Field Laboratory, Chinese Academic of Science, it is composed of 30 T resistive magnet insert and 10 T superconducting outsert which is cooled with forced flow of supercritical helium at 4.5 K supplied by cold box and valve box. The gaseous helium temperatures in valve box are measured by CLTS (Cryogenic linear temperature sensor). This paper presents the characteristics of CLTS, reports the magnetoresistance of the CLTS which is 5.8 m away from 40 T hybrid magnet centre when the 10 T superconducting outsert was in the field of excitation, and CLTS resistance offset for remanent magnetization. CLTS was not influenced by resistive magnet because of the small stray field of hybrid magnet 30 T resistive magnet.
       
  • Simulation of Natural Convection Boiling Heat Transfer for Refrigerant
           R-134a Flow in a Metal Foam Filled Vertical Tube

    • Abstract: Publication date: Available online 14 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Ali Samir, Ihsan Y. Hussain Natural convection boiling heat transfer for Refrigerant R-134a flow in a metal foam filled vertical tube is numerically investigated in the present work by using the Multiphase Mixture Model MMM at constant heat flux for both transient and steady state behavior under different parameters. The effect of changing imposed heat flux, porosity, PPI (pore per inch), and tube diameter was analyzed. It is found that liquid saturation will reach its minimum value at the exit, and the dry out point will be seen always at the 2nd half of the tube length. Results also show that smaller tube diameter and higher porosity for the same PPI caused a higher temperature variation over the entire metal foam tube. Comparisons with previous works show good agreement.
       
  • Case study on solar water heating for flat plate collector

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Walaa Mousa Hashim, Ali Talib Shomran, Hasan 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 °C and 49 °C) 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.
       
  • Solar Absorption Chiller Performance Prediction based on the Selection of
           Principal Component Analysis

    • Abstract: Publication date: Available online 11 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Nasruddin, Nyayu Aisyah, M.I Alhamid, Bidyut B. Saha, S. Sholahudin, Arnas Lubis In this paper, a method to predict the performance of an absorption chiller using solar thermal collectors as the energy input is analyzed rigorously. Artificial Neural Network (ANN) is developed based on experimental data to predict the performance of the solar absorption chiller system at Universitas Indonesia. In order to perform ANN accurately, some parameters such as chilled water inlet and outlet temperatures, cooling water inlet and outlet temperatures, solar hot water inlet and outlet temperatures, hot water inlet and outlet temperatures, ambient temperature and fuel consumption flow rate are chosen as the input variables. In addition, a Principle Component Analysis (PCA) is used to reduce the number of input variables for performance prediction. Without sacrificing the ANN's prediction accuracy, PCA identified the sensitive variables from all input variables. The developed ANN model combined with PCA (ANN + PCA) shows good performance which has a comparable error with ANN model, specifically the configuration 9-6-2 (9 neurons, 6 inputs, 2 outputs) of the ANN + PCA model leads to a COP root-mean-square error of 0.0145.
       
  • Effect of Calcination Temperature on Microsturctures, Magnetic Properties,
           and Microwave Absorption on BaFe11.6Mg0.2Al0.2O19 Synthesized From Natural
           Iron Sand

    • Abstract: Publication date: Available online 9 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Martha Rianna, Timbangen Sembiring, Marhaposan Situmorang, Candra Kurniawan, Anggito P. Tetuko, Eko Arief Setiadi, Ignu Priyadi, Masno Ginting, Perdamean Sebayang The syntheses of BaFe11.6Mg0.2Al0.2O19 with calcination temperature variations of 900, 1050, and 1200 °C were conducted through a co-precipitation method to be used as Radar Absorbing Material. The raw materials used in the syntheses were: BaCl2, MgCl2, AlCl3 and natural iron sand from Kata Beach-Sumatera Barat, Indonesia. The material was characterized using XRD, FE-SEM, VSM, and VNA. The results confirmed that the structure of the barium hexaferrite crystal did not change due to the effect of calcination temperature. The optimum conditions properties obtained for BaFe11.6Mg0.2Al0.2O19 at a calcination temperature of 900 °C, Ms = 20.64 emu g−1, Mr = 9.89 emu g−1, Hc = 1708 Oe, and BHmax = 45800 GOe, respectively. In addition, the maximum reflection loss and the microwave absorption values obtained were −58.60 dB and 99.99% at a frequency of 10.91 GHz.
       
  • Characteristic Investigation of an Electrochemical-thermal Coupled Model
           for a LiFePO4/Graphene Hybrid Cathode Lithium-ion Battery

    • Abstract: Publication date: Available online 8 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Yuan Li, Fei Qi, Hao Guo, Zhiping Guo, Meiying Li, Wenliang Wu It is a promising development strategy to use LiFePO4/Graphene (LFP/G) hybrid cathode lithium-ion batteries for electric vehicles (EVs), which can simultaneously solve issues of the lengthy charging time and the battery pack heat. To capture the characteristic regulation of the temperature distribution, the working voltage, the current density, and the total heat generation of the LFP/G battery, an electrochemical-thermal coupled model for the LFP/G battery was developed through a new modeling method in ANSYS FLUENT. The experimental results showed that tendencies of the temperature distribution and the working voltage were not only agreed well with simulations, but also accurately verified the hottest area of the LFP/G battery. Further studies used the comparative analyses of the maximal temperature between the LFP/G battery and the conventional LFP battery at different discharged C-rates, the results indicated that the LFP/G battery could restrain the increase of temperature through reduced contact resistances. Our results suggested that the electrochemical-thermal coupled model could be used for electric vehicles battery management system applications.
       
  • Bree's diagram of a functionally graded thick-walled cylinder under
           thermo-mechanical loading considering nonlinear kinematic hardening

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Mohsen Damadam, Reza Moheimani, Hamid Dalir 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.
       
  • Evaluation and analysis of nanofluid and surfactant impact on
           photovoltaic-thermal systems

    • Abstract: Publication date: Available online 7 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Ali H.A. Al-Waeli, Miqdam T. Chaichan, Hussein A. Kazem, K. Sopian The use of Nanofluids as a heat transfer agent has spread and expanded as its thermal conductivity is higher than the base fluid, so its use has been increased in heat exchangers and PVT systems. In this study, water was used as a base fluid and nano-silicon carbide as an additive to improve the thermal conductivity of the resulted nanofluid and its thermophysical properties were studied using five surfactants. In this study, the stability time of nanofluid was the main variable investigated. The stability of nanofluid depends on the surfactant used to slow the suspended nanoparticles deposition in the emulsion. The deposition process significantly reduces the thermal conductivity of nanofluids and thus reduces heat transfer. The study results indicated that the time of nanoparticles suspended in emulsion depend mainly on the type of the surfactant used and the ultrasonication time. The used surfactants are: ammonium cetyl cetyl (CTAB), sodium dodecyl sulfate (SDS), tannic acid+ammonia solution, dodecylbenzenesulfonate (SDBS), and Sodium deoxycholate. Ammonium cetyl cetyl (CTAB) and tannic acid+ammonia solution gave the highest stability period (more than two months) with ultrasonication mixing time for six hours by adding 0.1 ml. The addition of larger amounts of surfactant (more than 0.75 ml) increased the stability time for all nanofluids used. The maximum stability time achieved was 88 days when cetyl cetyl (ammonium cTAB) was added by 0.5 ml. The density, viscosity, and thermal conductivity measurements showed that there was no significant change with the change of the surfactant used. The addition of larger amounts of surfactant (more than 0.5 ml) caused a very limited increase in the density and viscosity of nanofluids. It also caused a small reduction in thermal conductivity.
       
  • Flow characteristics of two dimensional classical and pulsating jet in
           crossflow at low Reynolds number

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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.
       
  • Numerical investigation of heat transfer enhancement in plate-fin heat
           sinks: effect of flow direction and fillet profilet

    • Abstract: Publication date: Available online 3 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): Ammar A. Hussain, Basim Freegah, Basima Salman Khalaf, Hossein Towsyfyan Many researchers have studied the thermal performance of heat sinks, however to the best knowledge of the authors, the effect of flow direction (place of fan) on the thermal performance of plate-fin heat sinks with fillet profile have not yet been investigated. In this paper, the investigation develops a computational fluid dynamics (CFD) model, validated through comparison with an experimental data from the literature, which demonstrates the effect of flow direction and fillet profile on the thermal performance of plate-fin heat sinks. In particular, a plate-fin heat sink with fillet profile subject to parallel flow has been compared with the conventional design (plate-fin heat sink without fillet profile subject to an impinging flow) and satisfactory results have been perceived. The results of this study show that the base temperature along with the thermal resistance of the heat sink is lower for the proposed design. Therefore, the developed approach has strong potential to be used to improve the thermal performance of heat sinks and hence to develop more advanced effective cooling technologies.
       
  • Hydrodynamics Investigation of Pepper Drying in a Swirling Fluidized Bed
           Dryer with Multiple-Group Twisted Tape Swirl Generators

    • Abstract: Publication date: Available online 3 January 2019Source: Case Studies in Thermal EngineeringAuthor(s): V. Chuwattanakul, S. Eiamsa-ard The present work aims to investigation the behavior of drying peppers in a swirling fluidized bed dryer (S-FBD) fitted with multiple twisted tape swirl generators. A multiple-group twisted tape swirl generator was located at the air inlet at the bottom of the bed. The effects of the superficial air velocity (U⁎=U/Umf = 1.0, 1.1 and 1.2) on the moisture content (MC), moisture content ratio (MR) and drying rate (DR) were examined. The experimental results showed that the S-FBD can reduce the moisture content of peppers more rapidly than a conventional fluidized bed dryer (FBD). The S-FBD gave a higher DR and decreased drying time compared to that of a FBD. The results also indicated that operation at higher superficial air velocities resulted in a greater DR, especially at the beginning stage of the drying process. For the S-FBD, the reduced of MC, MR and DR at a high superficial air velocity (U⁎=U/Umf = 1.2) was better than at low superficial air velocities (U⁎ = 1.0 and 1.1). Furthermore, five different drying models were evaluated to predict the performance of the S-FBD.Graphical abstractGraphical abstract for this article
       
  • Heat transfer enhancement and pressure drop of Fe3O4 -water nanofluid in a
           double tube counter flow heat exchanger with internal longitudinal fins

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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 
       
  • Analysis on the influence of the smoke block board on the entrainment
           phenomena near a mechanical exhaust vent

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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.
       
  • Thermodynamic performance analysis of a R245fa organic Rankine cycle (ORC)
           with different kinds of heat sources at evaporator

    • Abstract: Publication date: Available online 29 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Rithy Kong, Thoranis Deethayat, Attakorn Asanakham, Nat Vorayos, Tanongkiat Kiatsiriroat The first and the second law analyses of a 20kWe R245fa organic Rankine cycle (ORC) with low grade temperature heat sources were numerically studied. There were three different heat sources such as hot water, saturated steam, and combined hot water/saturated steam used to supply heat at the ORC evaporator. The heat source temperature was varied in a range of 80-110oC and the pinch temperature difference between the heat source temperature and the evaporating temperature was in a range of 1-10oC. The ORC condensing temperature was kept constant at 40oC. The results revealed that the combined hot water/saturated steam heat source provided a highest second law or exergy efficiency due to less irreversibility generated at the evaporator followed by the saturated steam and the hot water heat sources, respectively. The increase of heat source temperature at a specific pinch could increase the second law efficiency of the cycle. However, the increase of pinch value resulted in lower second law efficiency. In addition, for the below pinch zone, with the hot water/saturated steam heat source, the reduction of the hot water flow rate slightly enhanced the ORC second law efficiency as the exergy destruction below pinch was reduced. However, there was a limit that the flow rate should not be reduced below a specific value otherwise a very high heat exchanger area was needed.
       
  • Experimental study on width effects on downward flame spread over thin
           PMMA under limited distance condition

    • Abstract: Publication date: Available online 28 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Shuai Gao, Guoqing Zhu, Yunji Gao, Jinju Zhou In this paper, a series of burning experiments with the downward fire spread were carried out using 1 mm thick, 200 mm tall PMMA with different widths varying from 50 mm to 150 mm in 13 mm restricted distance. The fire propagation parameters were observed and analyzed, including flame shape, pyrolysis front, pyrolysis length, flame height, and fire spread rate. The major conclusions are summarized as follows: The trends of the pyrolysis fronts and pyrolysis lengths with different widths show the increasing development under the limited condition. The flame height increase linearly as a function of time with the largest increase in 150 mm, followed by 100 mm and 50 mm. The wider the sample width, the faster the flame spread rate, Moreover, flame spread rate and flame width are exponentially related under constrained conditions, and the flame spread rate is proportional to the flame width with power value of 0.24 lowering than 0.5 and 0.35 in unlimited distance. The phenomenon is due to limited distance in this paper, and the flame spread rate of thermal thin materials is mainly affected by net heat flux. The conclusions of the study are meaningful for fire protection and fire development mechanisms.
       
  • Hydrothermal analysis of Non-Newtonian second grade fluid flow on
           radiative stretching cylinder with Soret and Dufour effects

    • Abstract: Publication date: Available online 28 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Ahmadreza Shojaei, A. Jafarian Amiri, S. Saedi Ardahaie, Kh. Hosseinzadeh, D.D. Ganji The present paper examines the analytical approach of a second grade fluid flow along a stretching cylinder and the Soret and Dufour effects is also investigated on the problem. The flow is subjected to thermal radiation. A system of non-linear equations has been extracted using the mathematical modeling of a second grade fluid flow in a cylindrical coordinate system. Homotopy analysis method (HAM) was implemented to solve this problem which an excellent agreement between this method and the numerical approach was observed in the results. The effect of the following physical parameters on the velocity, temperature and concentration profiles has been investigated in this paper; viscoelastic parameter (We), curvature parameter γ, Dufour parameter (Du), Soret parameter (Sr), temperature exponent (n), effective Prandtl number Preff and Schmidt number (Sc), etc. moreover, the drag coefficient on surface along with heat and mass transfer rate are also investigated and presented in various tables. For instance, it is predicted that Simultaneous variations of Du and Sr has an inverse relation for heat and mass transfer rate. In this case increasing Du and decreasing Sr would cause a decrease in heat transfer rate along with an increase in mass transfer rate.
       
  • Experimental investigation on the flow behavior during the Solid particles
           lifting in a micro-bubble generator type airlift pump system

    • Abstract: Publication date: Available online 28 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Deendarlianto, Intan Supraba, Akmal Irfan Majid, Muhammad Reza Pradecta, Indarto, Adhika Widyaparaga The airlift pump system includes the both air and liquid inlet sections, and the vertical pipe as the transporting medium. The low performance of the concurrent airlift pump systems has promoted efforts to further improve performance in implementation of these devices in various conditions of real sediment transport on sea and lakebeds. In the present experimental study, we have modified the conventional airlift pump system by equipped our developed micro-bubble generators in the system. Here the three-phase flow behavior during the solid particle lifting of the micro-bubble generator type airlift pump system during the transient conditions is reported. The inner diameter of the vertical pipe of this airlift pump system was 50 mm. Several inclination angles of micro-bubble injection were used: 15°, 30°, and 45° from the horizontal. The working fluids were air and water. The tested solid particles were solid and coal with the averaged of particle diameters were 0.33 mm, 0.52 mm, and 0.81 mm. The ranges of supplied flow rates of liquid and air, QL and QG, were 7.0 m3/hr. ~ 9.0 m3/hr., 0.3 l/min ~ 0.8 l/min, respectively. The obtained visualization images were analyzed by using the developed image processing technique.As a result, it was obtained that (1) the optimum solid lifting performance was found under the slug flow pattern due to their buoyancy force, (2) main parameters such as the injected inclination angle of the micro-bubble generator, the liquid and gas volumetric flow rates, the averaged particle diameters, and the density of the lifted particles affect the ability of the micro-bubble generator type of the airlift pump system, (3) The used of micro-bubble generators in the air lift pump system will increase their capability to bring the solid particles upward at least 17% compared to conventional airlift pump systems.
       
  • 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.
       
  • A numerical investigation of Newtonian fluid flow with buoyancy, thermal
           slip of order two and entropy generation

    • Abstract: Publication date: Available online 23 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): N. Vishnu Ganesh, Qasem M. Al-Mdallal, Ali J. Chamkha In the present article, the Newtonian fluid flow problem with buoyancy and thermal radiation in non-linear form is investigated by considering the entropy generation. The boundary is mathematically modeled with slip conditions (velocity and thermal) of order two. The parameters for the slip conditions of order two are calculated from the slip parameters of order one. The governing PDE's and the corresponding BC's are derived and transformed into ODE's by suitable transformation. Fourth order RK with shooting method is utilized to solve the transformed non-dimensional governing equations along with the boundary conditions. The efficiency of the present type of thermal fluidic system can be increased by reducing the generation of entropy. In view of these, the influences of slip conditions of order two on the entropy generation number are discussed. It is found that the increase of second order velocity and thermal slip effects reduces the entropy generation. Furthermore, the significant results are discussed with buoyancy effects. The present research work suggests to increase the second order slip factors in order to achieve the higher efficiency in the present type of thermal fluidic system.
       
  • Thermal Analysis Evaluation of Direct Contact Membrane Distillation System

    • Abstract: Publication date: Available online 22 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Mohamed R. Elmarghany, Ahmed H. El-Shazly, Mohamed S. Salem, Mohamed Nabil Sabry, Norhan Nady In this work, thermal analysis evaluation for a membrane distillation (MD) system is experimentally calculated. Variable feed flow rates and feed temperatures are investigated by calculating the thermal efficiency, gained output ratio and specific energy consumption. The increase in the feed flow rate resulted in increasing the thermal efficiency by 97% and the gained output ratio from 0.31 to 0.60, while the specific energy consumption decreased from 2064 to 1037 kWh/m3. Enhanced thermal performance can be attributed to the turbulence flow and the short residence time due to the increased flow rate. On the other hand, increasing the feed temperature affect negatively on the thermal performance due to heat loss from the membrane cell to the ambient. An increasing in the feed temperature leads to the higher temperature difference between the cell and the ambient that decreased the thermal efficiency up to 34% and the gained output ratio from 0.96 to 0.6, while the specific energy consumption increased from 689 to 1037 kWh/m3.
       
  • Performance and emitted pollutants assessment of diesel engine fuelled
           with Biokerosene

    • Abstract: Publication date: Available online 22 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Noora Salih Ekaab, Noor Hussein Hamza, Miqdam T. Chaichan Iraq is suffering from kerosene surplus in the summer because kerosene consumption is significantly reduced. This product contains less sulphur than diesel, and it gains viscous and lubrication properties similar to those of diesel when mixed with a small percentage of biodiesel. The possibility of using biokerosene as a fuel instead of conventional Iraqi diesel was investigated. The fuel consumption was relatively increased by 5.56% and 5.19% when the studied biokerosene KB10 and KB20 blends were used while the engine's exhaust-gas temperatures and thermal efficiency were decreased. The biokerosene blends KB10 and KB20 also emitted lower concentrations of particulate matter (22.4%, and 25.63%), hydrocarbon (7.74%, and 21.93%), and carbon monoxide (15, and 20.31%) compared to diesel at small or medium engine loads. Nitrogen oxide concentrations increased by (2.11% and 4.57%) with KB10 and KB20, while the engine noise measurements were lower than those from diesel by (1.51% and 3.57%) for all tested engine-load ranges. The PM–NOx trade-off for biokerosene was the best among all tested blends.
       
  • Performance analysis of shell and tube heat exchanger: Parametric study

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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.
       
  • Prediction of heat transfer coefficient during quenching of large size
           forged blocks using modeling and experimental validation

    • Abstract: Publication date: Available online 21 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Yassine Bouissa, Davood Shahriari, Henri Champliaud, Mohammad Jahazi In this study, a new method is developed to predict an accurate convective heat transfer coefficient (HTC) during quenching of large size steel blocks, using a combination of 3D Finite Element (FEM) simulations and a progressive artificial neural network (ANN).The HTC profile of the first inputs used for FEM simulations were acquired from the literature to calculate the cooling temperature profiles at specific locations. The training of the ANN was set up between HTCs and their corresponding FEM-calculated temperature. Experimental validation was carried out by instrumenting a large size forged steel block during the quench process. The experimental cooling curves were used for validation of the FEM simulation, as well as for the prediction of new HTCs by simulating the ANN. Results show that the proposed method provides progressively more accurate predictions than the existing ones reported in the literature.A mean absolute percentage error (MAPE) of 1.47% was found between experimental and calculated cooling curves for the predicted HTC, further demonstrating a better prediction ability of the proposed method.
       
  • Optimization of energy saving gathering and transportation mode in a block
           of Tahe oilfield

    • Abstract: Publication date: Available online 21 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Yi Zhao, Lirong Yao, Lijun Liu, Ying Xu With the increase of water content and the number of shutdown wells in old areas, the existing gathering and transportation mode can no longer meet the energy saving demands of oilfield production for Tahe oil field. Therefore, it is an urgent need of oilfield production management to reduce energy consumption. In this paper, the temperature drop and pressure drop models of oil-gas-water three-phase flow were deduced theoretically, and for four wells in a block in Tahe oilfield, taking 30 ℃ as safe gathering and transportation temperature limit, operation parameters in three kinds of gathering and transportation modes, namely, single well gathering and transportation, branch connection gathering and transportation, and ring gathering and transportation, were determined. The energy consumption and operation cost were calculated, and the comparative analysis results showed that, for these four wells, the most energy saving gathering mode was the branch connection form of pipe network.
       
  • 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%.
       
  • Combustion analysis of hydrogen-diesel dual fuel engine with water
           injection technique

    • Abstract: Publication date: Available online 18 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Osama H. Ghazal In this paper, the effect of direct diesel injection timing and engine speed on the performance and emissions of CI engine operating on RCCI (H2/diesel mixture) coupled with water injection have been numerically investigated and validated. The simulation have been carried out using GT-Power professional software. A single cylinder dual fuel compression ignition model has been built. The diesel fuel was injected directly to the cylinder. The hydrogen and water were injected to the engine intake manifold and engine port with constant mass flow rate and constant temperature for all engine speed. During the simulation the engine speed was varied from 1000 – 5000 rpm and the diesel injection timing was varied from (−5° to −25 ° CAD). In addition, the optimized diesel injection timing for specific engine operation parameters has also been performed.The results show that, for specific injection timing and constant hydrogen and water mass flow rate, the increase of engine speed results in an increase in the cylinder temperature, engine brake power, brake specific fuel consumption and NO emissions; but decreases brake thermal efficiency. Moreover, the analysis performed shows that, the advanced injection timing decreases the engine power, brake thermal efficiency and CO emissions; but increases NO emissions.
       
  • Actual validation of energy simulation and investigation of energy
           management strategies (Case Study: An office building in Semnan, Iran)

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(s): Afshin Fathalian, Hadi Kargarsharifabad 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.
       
  • Investigation on smoke temperature distribution in a double-deck tunnel
           fire with longitudinal ventilation and lateral smoke extraction

    • Abstract: Publication date: Available online 13 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Xin Zhang, Zhisheng Xu, Tianxiao Ni, Jinzhi Peng, Jiawei Zeng, Qibing Ran A set of experiments is carried out in a 1/15 reduced-scale double-deck tunnel to investigate the effect of longitudinal ventilation and lateral smoke extraction on the temperature distribution. The factors of the longitudinal ventilation velocity and the location of fire source are considered under the heat release rate (HRR) of 23 kW. The thermal behavior of the tunnel is observed. The experimental results show that the upstream ceiling temperature decreases with the increase of longitudinal ventilation velocity, while the downstream ceiling temperature increases with the increase of longitudinal ventilation velocity. With the increasing of distance away from fire source, the dimensionless smoke temperature rise reduces exponentially along the tunnel ceiling. The upstream or downstream temperature of the upper tunnel at the location with the same distance away from the fire source is higher than that of the lower tunnel, and the maximum temperature difference can be reached 93 °C. With the longitudinal ventilation velocity at 0.516 m/s, the downstream smoke layering length are 8.35 m and 7.65 m longer than the upstream smoke layering length in the upper and lower tunnel, separately.
       
  • Performance comparison of BAPV and BIPV systems with c-Si, CIS and CdTe
           photovoltaic technologies under tropical weather conditions

    • Abstract: Publication date: Available online 12 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Nallapaneni Manoj Kumar, K Sudhakar, M Samykano This paper compares the performance of photovoltaics (PV) for building applications in two configurations: building applied photovoltaics (BAPV) and building integrated photovoltaics (BIPV). 32.7 kWp PV capacity is proposed for a roof building and its performance in BAPV and BIPV configurations with three PV technologies namely crystalline (c-Si), CIS, and CdTe is analyzed. Standard methodology with performance parameters such as energy yield (EY), yield factor (YF), capacity utilization factor (CUF), performance ratio (PR), and losses is used. It is found that the EY, YF, and year to year energy production variability of BIPV and BAPV technologies varies from 43700 to 46800 kWh, 1336.39 to 1431.19 kWh/kWp, and 1910 to 2100 kWh respectively. The CUF and PR vary from 15.25 to 16.33%, and 72.23 to 77.36% respectively. Irrespective of PV configuration and technology, observed losses due to the angle of incidence, spectral effects, effects of change in irradiance and module temperatures are observed to be −2.8%, −1 to −5%, and −7.4 to −13.6% respectively. Total system losses range from −22.6% to 27.8% causing a fair amount of loss in the PV efficiency. Among, three PV technologies, CdTe is observed to perform better than CIS, and c-Si.
       
  • Numerical investigation of heat transfers in the water jacket of heavy
           duty diesel engine by considering boiling phenomenon

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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.
       
  • INVESTIGATIVE STUDY OF THE THERMAL PERFORMANCE OF A TRIAL AIR SOLAR HEATER

    • Abstract: Publication date: Available online 11 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Hocine Mzad, Kamel Bey, Rabia Khelif, Abdessalam Otmani Solar collectors need to be inclined at the optimum angle to maximize the receiving energy. The evaluation of the thermal performance of solar air collectors is important for the proper design and sizing of the collector for a given application. In our experimental/theoretical study, which consists of a thermal performance investigation, we have sought to optimize the efficiency–temperature rise couple of the designed solar air heater by considering the appropriate assembling materials regarding the absorber, the glazing and the insulation. Obviously, efficiency is dependent on the orientation of solar collectors and the measured parameters climate conditions such as wind speed, solar radiation and ambient temperature. In order to achieve possible performance optimization of the receiver plane using a low number of variables and equations, the calculations were carried out considering four values of azimuth angle, γ = 0°, 22.5°, 45° and 67.5°, and by varying the tilt angle β by 5 degrees from 15° to 70°.
       
  • Numerical investigation of sand-basalt heat storage system for Beam-down
           Solar Concentrators

    • Abstract: Publication date: Available online 8 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Suhil Kiwan, Qusai R. Soud This study aims to investigate the performance of a novel combined receiver storage system (RSS) for beam down solar concentrator. The proposed system consists of large sand volume located at the ground underneath the secondary reflector of the beam-down tower. The top of the storage volume is covered by an absorber system which contains a thick black painted metal plate. The absorber plate absorbs the reflected solar flux and converts it to heat. The heat energy is then transferred to the storage media using metal rods. The performance of the thermal storage material of different mixing ratios of sand and basalt are investigated. The unsteady governing equations for the system are solved using a finite element heat transfer model. The model is validated and used to predict the temperature distribution inside the storage media of different conducting rods configurations. The utilization factor of the storage media for various cases is calculated and documented. The results showed that the utilization factor is in the range 0.53 to 0.73 depending on the conductive rods configuration and the sand – basalt mixture ratio.
       
  • Investigations on ablation for highly-intensified diesel engine piston
           material

    • Abstract: Publication date: Available online 7 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Qin Zhaoju, Jia Chuanfa, Zhang Weizheng, Wang Lijun With the improvement of the degree of diesel engine enhancement, the thermal load of the piston is greatly increased, and higher requirements is imposed on the ablation resistance of the piston material. Three kind of piston materials were selected and the ablation performance was analyzed through experiments and simulation calculations, then the ablation mechanism and ablation model of piston materials were analyzed. Results revealed that Ablation mechanisms of piston material are melting ablation and gas flow erosion. Al-Si alloy materials have poor anti-ablative properties. Al2O3f/Al-Si composites and aluminum borate whisker reinforced Al-Si matrix composites exhibited higher anti-ablation properties, which contributed by the dense structure and high yield strength at high temperature of the composites. Aluminum borate whisker reinforced Al-Si matrix composites has the best anti-ablative properties.
       
  • Miniature Vapor Compression Refrigeration System for Electronics Cooling

    • Abstract: Publication date: Available online 5 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Akasit Poachaiyapoom, Rattapon Leardkun, Somchai Wongwises A miniature vapor compression refrigeration system using R134a is investigated for electronics cooling. The system consists of four main components: an evaporator, a compressor, a capillary tube, and a condenser. The evaporator is a micro-channel heat sink with 106 rectangular cross-sectional channels. Each micro-channel has a depth of 450 μm, a width of 150 μm, a wall thickness of 150 μm, and a length of 20 mm. Experimental conditions include compressor speeds ranging between 3000 and 6000 RPM and heating power of 100 W, 150 W, and 200 W. The experimental results of the experiment show that increased compressor speed could reduce the surface temperature of the heater but also decrease the coefficient of performance (COP). The highest COP gained is 9.069 at a compressor speed of 3000 RPM and a heating power of 200 W, which yields the heater surface temperature of 73.3°C. This miniature vapor compression refrigeration system could be used for electronics cooling with the most suitable conditions at heating power of 200 W and compressor speed of 3000 RPM. However, the proposed system is not suitable for electronics cooling at a heating power of 100 W and 150 W, because the heater surface temperature is less than 40°C.
       
  • EXCESS AIR RATIO EFFECTS ON FLOW AND COMBUSTION CARACTERISTICS OF
           PULVERIZED BIOMASS (OLIVE CAKE)

    • Abstract: Publication date: Available online 5 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Abdallah Elorf, Brahim Sarh The aim of this paper is to study effect of excess air ratio (λ) on combustion dynamics of pulverized olive cake (OC) in a vertical furnace. Four cases namely (a), (b), (c) and (d) for the air inlet conditions with different excess air ratio (EAR) (λ=1.3, 1.7, 2.3 and 2.7 respectively) are studied. The numerical approach is based on Reynolds Average Navier-Stokes (RANS) equations. The chosen turbulence closure model is the k–ε model. For turbulence-chemistry interactions of the non-premixed combustion, a mixture fraction/PDF approach is used. The particles of OC are injected perpendicularly to the central axe of furnace near the lower base. This injection mode increases the particle residence time in the furnace. The mean size particles diameter is 70 μm. The OC thermal characteristics are determined from thermogravimetric analysis (TGA). A comparison is done between (a), (b), (c) and (d) cases for, flow topology, velocity contours, temperature distribution and species concentration profiles in several locations along the furnace. Results show that increasing excess air ratio dilutes the emission of CO and CO2 inside to the furnace, lowered the temperature in the furnace exit and reduced the visible flames lengths Lvisible.
       
  • Sensible Air Cool-Warm Fan with Thermoelectric Module Systems Development

    • Abstract: Publication date: Available online 4 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): S. Wiriyasart, P. Naphon, C. Hommalee An experimental investigation on the application of thermoelectric modules for cooling and heating supply air of the conventional fan system is performed. The thermoelectric cooling module is comprised of six thermoelectric plates, two cold water boxes and a hot water box. While the thermoelectric heating module is comprised of three thermoelectric plate, a cold and hot water boxes. The obtained results from the heating capacity of the sensible air cool-warm fan system are presented and compared with those from the conventional fan system (without thermoelectric module). It can be found that the minimum and maximum water temperature obtained from the thermoelectric module are 12 °C and 70 °C, respectively. For on-off modes every 5 minutes, average cool air obtained from the fan system with thermoelectric module is 2.0 °C lower than that without thermoelectric module while average warm air temperature is 2.5 °C higher than that without thermoelectric module. The obtained results are also expected to guideline that will allow designing and developing the sensible air cool-warm fan system with thermoelectric module system to higher thermal performance.
       
  • Spacing Effects on Downward Flame Spread over Thin PMMA Slabs

    • Abstract: Publication date: Available online 4 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): Hui Zhu, Yunji Gao, Rongliang Pan, Bo Zhong To explore the flame spread mechanism over non-charring materials, the downward flame spread over polymethyl methacrylate (PMMA) samples is studied experimentally under the spacing scenarios of 2 mm, 7 mm, 13 mm, 19 mm and 25 mm. The experimental results show that: (1) As the spacing increases, the flame height, the length of the preheating zone and mass loss rate all increase first and then decrease. When the spacing is 13 mm, each value reaches the maximum. (2) As the spacing increases, the flame spread speed increases first and then decreases, approaching the single burning PMMA slab finally. In this study, a heat transfer model is proposed to examine the spacing effect over PMMA slabs. According to experimental results, a correlation between the flame spread rate and spacing is derived. Besides, experimental data agree well with the theoretical model.
       
  • Influence of the oblique fin arrangement on the fluid flow and thermal
           performance of liquid cold plate

    • Abstract: Publication date: September 2018Source: Case Studies in Thermal Engineering, Volume 12Author(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.
       
  • Numerical Heat Transfer Enhancement using Different Nanofluids Flow
           through Venturi and Wavy Tubes

    • Abstract: Publication date: Available online 1 December 2018Source: Case Studies in Thermal EngineeringAuthor(s): M. Hatami, A. Kheirkhah, H. Ghanbari-Rad, D. Jing In this study, the k-ε turbulence model with enhanced wall function using ANSYS commercial software is used for studying the effect of convergent/divergent sections on the heat transfer of nanofluids in two different cases. In first case, a venturi is modeled with different nanoparticles (SiO2, Al2O3 and CuO) and in second case, a wavy tube with different sinusoidal wall functions (sin(x/2), sin(x) and sin (2×)) is considered. Results of first case revealed that SiO2-water had the most surface Nusselt number among the other nanofluids and outcomes of second case confirmed that when the wave length is smaller (for sin (2×)) the temperatures near the walls increased and consequently the surface Nusselt number in peak areas are greater among other tested wall functions.
       
  • Numerical evaluation of the effects of fire on steel connections; Part 2:
           Model results

    • Abstract: Publication date: Available online 29 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Rohola Rahnavard, Robert J. Thomas The resistance of beam-to-column connections to fire is an important consideration for the design of steel moment frames. The authors seek to study the effect of fire on such connections using finite element modeling in ABAQUS. The previously published first part of this paper detailed and validated the simulation technique by comparing model results to experimental results reported elsewhere in the literature. This, the second part of the paper, seeks to demonatrate the performance of four types of connections exposed to thermal loading: (1) bolted end plate, (2) bolted cover plate, (3) bolted tee, and (4) welded cover plate. A numerical study was performed to quantify the effects of thermal loading on beam buckling, displacement, rotation, connection stiffness, and moment-rotation behavior at temperatures between 20 and 900 °C. The bolted end plate connection exhibited the highest resistance to thermal loading with a significantly lower degree of degradation in connection performance compared to the other three connection types.
       
  • Effect of generator load on hybrid heat recovery system

    • Abstract: Publication date: Available online 29 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Hassan Jaber, Mahmoud Khaled, Thierry Lemenand, Mohamad Ramadan Heat recovery is the reutilization of lavished thermal energy. This paper proposes a hybrid heat recovery system that utilizes exhaust gases of a generator to heat water and produce electricity using thermoelectric generators. The system is composed of a concentric tank with a copper tube passing through it. At the inner surface of the tube, a layer of TEGs is located. The main purpose of the paper is to study the effect of changing the load of the generator on the water temperature and power generated. Knowing that 100 TEGs are utilized, results show that 47 °C hot water and 141 W are produced when load is 10 kW. It increases to 97 °C hot water and 1412 W when the generator load is 38 kW (14.12 W per TEG).Graphical abstractGraphical abstract for this article
       
  • Combustion performance of domestic gas cookers with swirling strip-port
           and normal round-port on various natural gas compositions

    • Abstract: Publication date: Available online 28 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Zhiguang Chen, Yangjun Zhang, Chaokui Qin, Pengfei Duan This document aims to assess the different performance of swirling strip-port and normal round-port domestic gas cookers with gas property fluctuation and propose suitable structure design parameter for both port types. Comparing with normal round-port gas cookers, swirling strip-port samples are not advantage on aspects of thermal efficiency and CO emission, but in term of NOx emission it performs very well which can effectively control NOx emission in a suitable range and improve gas cooker′s adaptive capacity, when natural gas is interchanged. It is easier to qualify CO emission with low NOx emission for swirling strip-port gas cookers, though it will sacrifice a part of thermal efficiency, while normal round-port gas cookers are easier to qualify CO emission with high thermal efficiency. The burner head design structure parameters of normal round-port gas cookers which can well adapt natural gas interchange are port thermal intensity in 7.2~8.4 W/mm2 and structure factor ε in 30~40, as well as swirling strip-port gas cookers are port thermal intensity in 8.0~11.5 W/mm2 with structure factor ε in 35~45.
       
  • Effect of parameters on moisture removal capacity in the desiccant cooling
           systems

    • Abstract: Publication date: Available online 27 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Ali Alahmer, Sameh Alsaqoor, Gabriel Borowski A mathematical model was developed to investigate the effect of crucial operating parameters, such as process inlet humidity ratio, inlet volume flow rate, R/P ratio (reactivation/process air flow), regenerative temperature and rotational speed on the performance of desiccant wheels in hot and humid climates, using wound silica gel and molecular sieve desiccants. The desiccant wheels were designed to operate in two modes, specifically, with 90° for reactivation and 270° for process (1:3 split) as well as with 180° for reactivation and 180° for process (1:1 split). The main results enabled to make the following observations: (i) higher regeneration air temperature leads to an improvement of dehumidification and reduction of the thermal coefficient of performance COPth, (ii) an increase in the process inlet volume flow rate causes a reduction in the process removed moisture; (iii) the greater R/P ratio is required to remove more moisture, while a lower R/P ratio implies the lower power consumption for regeneration; (iv) silica gel desiccant is preferred when greater moisture removal is required at high inlet relative humidity, while molecular sieve desiccant is preferred when low dew point is required at low inlet relative humidity.
       
  • TEMPERATURE IN PAVEMENT AND SUBGRADE AND ITS EFFECT ON MOISTURE

    • Abstract: Publication date: Available online 26 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): B.B. Teltayev, E.A. Suppes This paper gives the results of experimental research of temperature variation and its effect on distribution of moisture in pavement and subgrade of a highway located in the eastern region of Kazakhstan. The sensors consisting of two elements have been used to measure temperature and moisture. The first of them is designed for measurement of temperature and based on the effect of thermal resistance, and the second one based on diamagnetic penetration allows measuring of moisture.Peculiarities of temperature variation in time in pavement layers and points of subgrade, temperature distribution in the depth at different time moments have been described. Important characteristics have been determined – duration of a frozen condition and freezing, average rates of freezing and defreezing in points of pavement and subgrade located in various depths.Quantity of unfrozen water in subgrade soil depends on negative temperature and initial moisture and it is satisfactorily approximated by semi-logarithmic function.
       
  • A Lattice Boltzmann Investigation of Two-Phase Natural Convection of
           Cu-water Nanofluid in a Square Cavity

    • Abstract: Publication date: Available online 26 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Danjie Xu, Yang Hu, Decai Li A numerical investigation of two-phase natural convection of Cu-water nanofluid in a square cavity is conducted by using a novel volume fraction-thermal lattice Boltzmann method to solve the governing equations of the flow field, temperature field, and nanoparticle volume fraction distribution field. The study explores the effects of the variable nanoparticle volume fraction at different Rayleigh numbers (103≤Ra≤106) and initial nanoparticle volume fractions (0.01≤ϕinitial≤0.05) on streamlines, isotherms and the Nusselt number. The results have shown that the Nusselt number along side walls would decrease when the Rayleigh number is large, with the opposite effects on parts of the side walls when the Rayleigh number is small. The relative difference of Nusselt number has a positive correlation with both the Rayleigh number and the initial nanoparticle volume fraction. When the Rayleigh number or the initial nanoparticle volume fraction is relatively large, the slip mechanisms of nanoparticles play an important role, and the two-phase model should be adopted instead of the conventional homogeneous one-phase model.
       
  • Numerical Simulation Study of Novel Air-Cooled Condenser with Lateral Air
           Supply

    • Abstract: Publication date: Available online 24 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Yu Zhou, You-liang Cheng, Ning Zhang, Hong-bo Shi Uneven distribution of internal temperature and air flow field are considered to be the essential defects of the Λ-frame air-cooled condenser (ΛACC) in a power plant. Lateral air supplement to a noble, truncated cone-shaped air-cooled condenser (TCACC) is investigated by mean of numerical simulation to solve these problems fundamentally and improve the performance of the air-cooled condenser (ACC) obviously. A Circular ring, installing at the bottom of the heat transfer surface, the structure of which is optimized. According to compare a series of ACCs in different fan inlet air conditions, the TCACC with a lateral air supply (TCACCL) is obtained for heat transfer and safety. The numerical results indicate that the lateral air supplement is an effective way to improve the thermo-flow performance of TCACC.
       
  • Performance analysis and optimal parameters of a direct evaporative pad
           cooling system under the climate conditions of Morocco

    • Abstract: Publication date: Available online 23 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Azzeddine Laknizi, Mustapha Mahdaoui, Abdelatif Ben Abdellah, Kamal Anoune, Mohamed Bakhouya, Hassan Ezbakhe In this study, a direct evaporative pad cooling system to be used for a poultry house is simulated under the climate conditions of six Moroccan cities. The objective is to optimize the parameters affecting the performance of the system for each city. The thermodynamic properties of humid air are extracted from the open source program CoolProp, and a computer program is used to perform a parametric study in order to find the impacts of the pad thickness and the frontal velocity on system's performance. Simulations have been conducted on cellulosic pad cooling and obtained results show that the system has the potential to lower the outdoor temperature during the hottest period with a coefficient of performance higher than 80, while the average rate of water consumption is higher than 3.3kg per hour.
       
  • Investigation on the Accurate Calculation of the Temperature Field of
           Permanent Magnet Governor and the Optimization Method of Heat Conduction

    • Abstract: Publication date: Available online 22 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Wang Lei, Jia Zhenyuan, Zhang Li Since the heat resistance capacity of permanent magnet governor's key components is poor and high temperature will affect the governor's lifespan, it is extremely necessary to conduct the study on temperature field. Taking the 250 kW permanent magnet governor which is researched and developed independently as an example, the present paper focuses on the present problem of magnetic-thermal unilateralism coupling field's failure of precisely calculating the transmission torque and temperature distribution. The paper proposes adopting bidirectional coupling calculation method, considering temperature's effect on the performance of magnetizer as well as permanent magnet's magnetic field and magnetic characteristics’ influence on temperature field, so as to realize the accurate calculation of magnetic field and thermal field. In addition, simulation results of unilateralism and bidirectional coupling have been verified through experiments. It turns out that the magnetic-thermal bidirectional coupling calculation is closer to the temperature value measured in the experiment, with an error only within 2%, which proves that the bidirectional coupling calculation is more accurate and is of great importance to guiding the design of permanent magnet governor's magnetic field. Meanwhile, as most of the current simulation models neglect the air gap of the connection between the actual magnetizer and the steel disc's rigging screw, the calculation of temperature field is not precise enough. The present paper has conducted a temperature simulation comparison between no air film and air films of varying thicknesses. In this way, it is discovered that the thickness of air film exerts an apparent effect on temperature field, with the highest temperature difference up to 22℃. Aiming at the issue of air film's reduction of heat conduction performance, the present paper proposes that the magnetizer disc and steel disc employ explosive welding to form composite board craft, so as to optimize heat condition. In addition, experiments have been conducted for verification. It has been proved that the temperature in the situation where explosive welding heat conduction optimization method is used is lower than the temperature when air film's thickness is 0.15 mm by 7~10℃, thereby greatly increasing the efficiency of heat conduction and guaranteeing the steady as well as reliable operation of permanent magnet governor.
       
  • Bioethanol production from different Matooke peels species: A surprising
           source for alternative fuel

    • Abstract: Publication date: Available online 22 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): Abdulfatah Abdu Yusuf, Freddie L. Inambao Conversion of agro-industrial wastes to energy is an innovative technique for waste valorization and management which reduces exhaust emissions and offers socioeconomic benefits. The goal of this paper is to investigate the feasibility of producing bioethanol from a renewable and sustainable energy resource which is matooke species peels through a fermentation process using Saccharomyces cerevisiae. The properties of the bioethanol were measured according to relevant ASTM standards and compared, and analyzed by gas chromatography. The results shows that the bioethanol yield for the two samples through fermentation process was found to be 71.54 g/L for the Mbwazirume variety and 70.57 g/L for the Nakyinyika variety, and the selected parameters have a strong correlation with the ethanol yield, as analyzed by ANOVA. In conclusion, matooke bioethanol properties are within the acceptable range of standard ethanol and gasoline. These matooke bioethanol can be used in the development of further experiments on performance and exhaust emissions test in spark-ignition (SI) engines.
       
  • Investigation of MHD Eyring-Powell fluid flow over a rotating disk under
           effect of homogeneous-heterogeneous reactions

    • Abstract: Publication date: Available online 15 November 2018Source: Case Studies in Thermal EngineeringAuthor(s): M. Gholinia, Kh. Hosseinzadeh, H. Mehrzadi, D.D. Ganji, A.A. Ranjbar In this research, the characteristic of the Eyring-Powell Nano fluid flow due to rotating dick with various physical impacts, such as slip flow, magnetic field along with homogeneous-heterogeneous reactions is analyzed. Higher order non-linear expressions are converted to ordinary first-order differential equations and then solved using the numerical Method (4th–5th-order Runge–Kutta–Fehlberg) in Maple-18 software. The main view of this article is to investigate the impact of parameters and numbers in the problem on velocity, temperature and concentration profiles. Conclusions indicate that: the temperature profile has shown a dual behavior in terms of changes Nt and pr. T (ζ) is increased with increasing thermophoresis parameter (Nt) and is decreased with increasing Prandtl number (Pr).
       
  • 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.
       
  • 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.
       
  • 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.
       
  • 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
           Container

    • 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.
       
  • PRELIMINARY ASSESSMENT OF A SOLAR ABSORPTION AIR CONDITIONING PILOT PLANT

    • 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.
       
  • 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
       
  • 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.
       
  • 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.
       
  • 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.
       
  • 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.
       
  • 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.
       
  • 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.
       
 
 
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