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CFD Letters
Number of Followers: 8  Open Access journalISSN (Print) 2180-1363 Published by ISSR Journals  [3 journals]
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- Application of Box- Behnken Design with Response Surface Methodology to
Analyse Friction Characteristics for Corrugated Pipe via CFD
Authors: Azraf Azman, Mohd Zamri Yusoff, Azfarizal Mukhtar, Prem Gunnasegaran, Ng Khai Ching, Ahmad Shah Hizam Md Yasir
Pages: 1 - 13
Abstract: Due to the fact that modern technologies are getting smaller and more compact and are anticipated to perform better, there has been an increase in interest in heat transfer enhancement employing hybrid nanofluids in tubes and channels in recent years. This study seeks to establish an outward saw tooth corrugated wall model-based predictive friction characteristic for internal tube flow. Computational Fluid Dynamics (CFD) was used to simulate the model numerically. The response behaviour study was then conducted utilising the Design of Experiment (DOE) and the Response Surface Methodology (RSM). The established surrogate model has led to the consideration of RSM. In this study, the DOE was executed by utilising the Box-Behnken Design (BBD) method with two-level factorial by considering three parametric factors which are: (a) 10000 to 30000 axial Reynolds number, Re, (b) 1mm to 4mm wave amplitude, a, and (c) 5mm to 20mm wavelength, lw. The results showed that the expected response surface values are consistent with the CFD values and that the predictive model is therefore reliable. The R-squared (R2) value is 98.25%, indicating that the model can predict new observations. The wavelength and wave amplitude show significant factors influencing the friction factor which is -0.11235 and 0.14861 respectively and this is based on the normal plot of the effect from the regression model from RSM. These results provide data for estimating the geometric characteristics of tube corrugated wall.
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.113
Issue No: Vol. 15, No. 7 (2023)
- Study on the Effects of Individual Pitot Tube Inlet of a Bladeless Tesla
Microturbine using Numerical Analysis
Authors: Ernnie Illyani Basri, Adi Azriff Basri, Farah Nur Diyana Salim
Pages: 14 - 30
Abstract: In this paper, a comprehensive numerical analysis of a bladeless Tesla microturbine is presented. Various studies on the effects of Tesla design parameters have shown promising results. However, the limitations associated with the inherent nozzle design have often highlighted the low efficiency of the turbine. Therefore, the study was carried out using computational fluid dynamics (CFD) to demonstrate the efficiency of the turbine as a function of the performance of different openings of the inlet nozzles, i.e., as 1-opening and individual pitot tube opening. In this work, a validation study was performed with the existing manuscript before further investigating the effects of the different openings of the inlet nozzles. The results show that the configuration of 4 inlets with 4 openings (4i4o) results in higher velocity and pressure distribution compared to 4 inlets with 1 opening (4i1o). Consequently, 4i4o obtained a higher torque value compared to 4i1o with a difference of 10%. Hence, the thrust and efficiency values for the 4i40 were 33.69% and 34.30%, respectively, higher compared to the 4i1o. The performance of the Tesla turbine with the specified optimal configuration increased very significantly compared to the previous research studies. It can be concluded that the introduction of the functional theory of the ‘pitot-tube’, which considers the gaps individually by having a separate inlet for each of them, had a great impact on the performance of Tesla turbine.
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.1430
Issue No: Vol. 15, No. 7 (2023)
- Significance of Cattaneo-Christov Heat Flux on Chemically Reacting
Nanofluids Flow Past a Stretching Sheet with Joule Heating Effect
Authors: K. Sandhya Rani, G. Venkata Ramana Reddy, Abayomi Samuel Oke
Pages: 31 - 41
Abstract: This paper examined the significance of Cattaneo-Christov's theories on the flow of chemically reacting fluid past a stretching surface with thermophysical parameters. The mathematical modelling of the physical problem was represented by partial differential equations. The set of partial differential equations was simplified by employing suitable similarity variables to obtain the system of coupled nonlinear ordinary differential equations. The transformed equations were later solved using the spectral relaxation method. The spectral relaxation method employs the basic concept of the Gauss-Seidel relaxation techniques. The outcome of this method was presented in graphs and tables. The thermal radiation parameter was found to enhance the velocity and temperature distributions. Also, the effect of the magnetic field parameter was found to decline the velocity profile. It was found that the Brownian motion parameter greatly influences the velocity as well as temperature profiles
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.3141
Issue No: Vol. 15, No. 7 (2023)
- Radiative Heat Source Fluid Flow of MHD Casson Nanofluid over A Non-Linear
Inclined Surface with Soret and Dufour Effects
Authors: P. Raja Sekhar, S. Sreedhar, S. Mohammed Ibrahim, P. Vijaya Kumar
Pages: 42 - 60
Abstract: In this article, the impact of MHD Casson Nanofluid boundary layer flow, over an inclined extending surface with thermal radiation, heat source/sink, Soret and Dufour, is scrutinized. The model used in this study is based on the Buongiorno model of the thermal efficiencies of the fluid flows in the presence of Brownian motion and thermophoresis properties. The non-linear problem for Casson Nanofluid flow over an inclined channel is modeled to gain knowledge on the heat and mass exchange phenomenon, by considering important flow parameters of the intensified boundary layer. The governing non-linear partial differential equations are changed to ordinary differential equations and are afterward illustrated numerically by the homotopy analysis method (HAM). Numerical and graphical results are also presented in tables and graphs. It has been noticed that increasing the inclination parameter reduces the amount of friction experienced by the surface, but it has the opposite effect on the Nusselt number and the Sherwood number. In the concentration field, the inclination parameter reveals a decreasing trend, in contrast to the chemical reaction rate parameter, which reveals an increasing trend in the opposite direction. Likewise, the present results are noticed to be in an excellent agreement with those offered previously by other authors. Finally, some of the physical parameters in this study, which can serve as improvement factors for heat mass transfer and thermophysical characteristics, make nanofluids premium candidates for important future engineering applications
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.4260
Issue No: Vol. 15, No. 7 (2023)
- The Effect of Tortuosity on Wall Shear Stress of Porous Scaffold
Authors: Hasan Basri, Akbar Teguh Prakoso, Zainal Abidin, Ardiansyah Syahrom, Imam Akbar, Dendy Adanta
Pages: 61 - 73
Abstract: This study aimed to investigate the effect of morphology on permeability and fluid wall shear stress of porous scaffold. Fluids passing through the scaffold were analyzed using the computational fluid dynamics (CFD) method, and tortuosity was analyzed using the finite-different analysis (FDA) method. Based on the results, the higher the porosity, the higher the permeability. In contrast, by increasing the tortuosity, the permeability decrease. Then, control curvature in the negative Schwarz p design has the potential to increase the permeability, consequently, decrease the specific surface area. Therefore, the design negative Schwarz p was proposed met the requirements for a good implant which the permeability value was in the range of trabecular bone.
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.6173
Issue No: Vol. 15, No. 7 (2023)
- Carbon Nanotubes Flow on Mixed Convection of Aligned Magnetohydrodynamics
over a Static/Moving Wedge with Convective Boundary Conditions
Authors: Siti Shuhada Ishak, Nurin Nisa Mohd Noor Azhar, Nurul Syafiqah Nazli, Mohd Rijal Ilias, Roselah Osman, Zubaidah Sadikin, Abdul Rahman Mohd Kasim, Nurul Farahain Mohammad
Pages: 74 - 91
Abstract: Nanotubes have been designed to be significantly larger than any other material, and these cylindrical carbon molecules have exceptional properties that are important for nanoscience and nanotechnology. Due to their exceptional thermal conductivity and mechanical and electrical properties, carbon nanotubes are used as additives to improve heat transfer in various industrial applications. The study analyzed a steady, two-dimensional, carbon nanotubes (CNTs) flow on aligned magnetohydrodynamics mixed convection over a static or moving wedge with convective boundary conditions. The CNTs used are single-wall carbon nanotubes (SWCNTs), multi-wall carbon nanotubes (MWCNTs), and water as the base fluid. The similarity transformation was used to reduce the partial differential governing equations into ordinary differential equations. Then, the reduced equations were solved using fourth-fifth order Runge–Kutta–Fehlberg and coded into Maple Software. The results of velocity and temperature profiles were illustrated graphically while the results of skin friction coefficient and Nusselt number were presented in tabulated data. It is found that the velocity profiles increase, and temperature profiles decrease when the angle of aligned magnetic field parameter, the interaction of magnetic parameter, convective parameter, and total angle of the wedge parameter number increase. For case where Biot number and volume fraction of nanoparticles parameters increase, the velocity profiles decrease, and temperature profiles increase. SWCNTs have increased skin friction and Nusselt numbers due to their higher density and thermal conductivity compared to MWCNTs. The finding of this study will benefit the who works in research and development in a range of industries and the mathematics body of knowledge as it provides new information to people who are interested in this field.
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.7491
Issue No: Vol. 15, No. 7 (2023)
- Magnetohydrodynamic Effect in Mixed Convection Casson Hybrid Nanofluids
Flow and Heat Transfer over a Moving Vertical Plate
Authors: Norsyasya Zahirah Mohd Zukri, Mohd Rijal Ilias, Siti Shuhada Ishak, Roselah Osman, Nur Asiah Mohd Makhatar, Mohd Nashriq Abd Rahman
Pages: 92 - 111
Abstract: The current study examined the effect of nanoparticles shapes on magnetohydrodynamics (MHD), Casson hybrid nanofluids flow, and heat transfer over a moving vertical plate with convective boundary condition. In this study, a base fluid (water) was infused with silver (Ag) and titanium oxide (TiO2). Similarity transformation techniques are used to convert the partial differential equations of Casson hybrid nanofluids to an ordinary differential equation, which are then solved numerically by applying the implicit finite difference, Keller box method. The velocity and temperature profiles, skin friction, and Nusselt number of Casson hybrid nanofluids were graphically illustrated and numerically tabulated. The results indicate that platelets have the highest velocity and temperature profiles, followed by cylindrical, bricks, and spherical nanoparticles. It was discovered that as the parameters aligned angle of the magnetic field, magnetic field interaction, mixed convection, Casson hybrid nanofluids, and Biot number increase, the velocity increases while the temperature decreases. As the volume fractions of Ag and TiO2 nanoparticles increase, the velocity decreases while the temperature increases. Except for the Casson hybrid nanofluids parameter, the skin friction and Nusselt number increase as the aligned magnetic angle, magnetic field interaction, mixed convection, volume fraction of Ag and TiO2 nanoparticles, and Biot number is increased. For all parameters, the plate with the condition moving with the flow has the highest velocity and Nusselt number, followed by the static and moving against the flow plates. When it comes to temperature and skin friction, the plate that is moving against the flow has the highest temperature, followed by the plate that is static and moving along the plate. The findings of this work will contribute to the corpus of knowledge in mathematics by providing fresh information for mathematicians interested in future research on Casson hybrid nanofluids.
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.92111
Issue No: Vol. 15, No. 7 (2023)
- Entropy Generation of Three-Dimensional Williamson Nanofluid Flow Explored
with Hybrid Carbon Nanotubes over a Stretching Sheet
Authors: P.S.S. Nagalakshmi, N. Vijaya, Shaik Mohammed Ibrahim
Pages: 112 - 130
Abstract: The current study simulated the three-dimensional Williamson nanofluid flow model over a stretching sheet in the presence of Cason parameter explored with hybrid carbon nanotubes. The governing equations are modelled and interpreted using adequate similarity transformations and physical phenomena to convert into nonlinear coupled ordinary differential equations. In order to solve these equations, a Python coding program is used with an open-source boundary value problem solver. The obtained numerical results are validated with related literature results. The results are interpreted through graphs and tables with thermos-physical parameters like thermal Peclet number. It is found that the growth rate of heat transfer from fluid to wall with booming non-linear thermal radiation, radiation, and thermal Peclet number parameters
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.112130
Issue No: Vol. 15, No. 7 (2023)
- Improvement of Plate-Fin Heat Exchanger Performance with Assistance of
Various Types of Vortex Generator
Authors: Ali Sabri Abbas, Ayad Ali Mohammed
Pages: 131 - 147
Abstract: A 3-dimensional incompressible laminar flow and heat-transfer in a plate-fin heat exchanger (PFHE) where investigated numerically in this article. The influence of mounting a longitudinal vortex generator (LVG) on the offset rectangular-triangular fin (ORT) in the PFHE, on thermal and hydro-dynamic fields are presented. The novelty of this study is by attaching a LVG to an offset strip fin (OSF) surface. The cases of study for the PFHE are established, by using a built-in rectangular winglet pair type RWP longitudinal vortex generator carried out and fitted on this fin to improve the convective heat transfer of the (ORT) fin while minimizing pressure loss. The upper and lower plates are exposed to constant heat flux and the working fluid is air where chosen under a laminar range of RE (600 to 1400). The laminar flow and heat-transfer are governed by continuity, momentum and energy equations. ANSYS FLUENT (2021 R1) is used to get the numerical results, based on the finite volume method. The performance of the VG is assessed for an optimum winglet attack angle (45°), as well as by modifying the geometrical size parameters, namely the height and placement (L) of the RWP LVG. The result shows that the Nusselt number reaches its optimum enhancement values by using a common flow up CFU built-in rectangular winglet pair type RWP VG with a height and entrance length of (h=1.25mm, L=0.5mm), by 22.23% as compared with base case configuration (ORT). Finally, a two more LVG are tested with the optimum conditions of the RWP, which they are a delta winglet pair (DWP) and trapezoidal winglet pair (TWP). In addition, the temperature fields for the primary and secondary flows were shown in contour and streamline diagrams
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.131147
Issue No: Vol. 15, No. 7 (2023)
- Sensitivity of TBL Wall-Pressure over the Flat Plate on Numerical
Turbulence Model Parameter Variations
Authors: Biplab Ranjan Adhikary, Ananya Majumdar, Atanu Sahu, Partha Bhattacharya
Pages: 148 - 174
Abstract: A two-fold sensitivity of the zero-pressure gradient (ZPG) turbulent boundary layer (TBL) wall-pressure spectrum to different RANS model parameters is investigated for a flat plate case, which is a close approximation to the aircraft fuselage or wing. The alteration in the mean square pressure fluctuations due choice of semi-empirical pressure model and the choice of computational model parameters like solver, near wall grid clustering, measuring location, and flow velocity are separately studied. The underlying effect of different TBL parameters in the said sensitivity has been studied while numerically replicating wind tunnel experiments and in-flight tests considering different RANS configurations. Initially, the best-predicting pressure spectrum models are selected by comparing them with available in-flight and wind tunnel test data. Subsequently, the accuracy of all the individual model parameters in predicting mean TBL flow quantities like wall shear stress, boundary layer thickness, displacement thickness, momentum thickness, etc., and eventually mean square pressure (MSP) is estimated. The sensitivity of the mean square pressure fluctuations value to the TBL flow quantities and the near-wall grid clustering is observed to be significant. In general, family of models is found to be best in terms of numerical convergence and closeness when compared to the experimental MSP values. family of models is suggested to be avoided while estimating MSP in flat plate TBL case
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.148174
Issue No: Vol. 15, No. 7 (2023)
- Performance Evaluation of Different Texture Material Masks to Reduce
Airborne Infection
Authors: Fatma A-M. Kassem, Ahmed Farouk AbdelGawad, Mofreh M. Nassief, A. E. Abu El-Ezz, S.H.Samha, Mohamed Adel
Pages: 175 - 193
Abstract: At the end of 2019, the COVID-19 virus began to appear and quickly spread throughout the world. It transmits the infection to the respiratory tract by the transmission of pathogens within bioaerosols during speaking, coughing, and sneezing. Therefore, understanding the dynamics of aerosols plays an important role in developing mitigation strategies against droplet infections. Computational modeling, using fluid and computational dynamics, has become a useful feature in studying and visualizing the diffusion of micro-droplets that are difficult to reach using experimental methods. Through this study, the effects of using cloth face masks and social distancing, both recommended by the World Health Organization to the general public to avoid rapid transmission of COVID-19, were determined. This study made a comparison between different structural masks and the difference between social distancing with different porous masks at the droplet diameter during breathing from 0.5 µm to 2.5 µm. The results showed the effectiveness of wearing masks in reducing the risk of infection transmission. Also, with lower mask porosity, lower air permeability means higher filtration efficiency, trapping airborne particles more effectively, especially for small infection-carrying particle sizes, and, therefore, lowering the required social distancing. From the comparison, it is concluded that sample 6 has the highest efficiency of 82.9% compared to other samples (1, 2, 3, 4, and 5), which have efficiencies of 77.1%, 77.1%, 74.3%, 80.0%, and 65.7%, respectively
PubDate: 2023-05-29
DOI: 10.37934/cfdl.15.7.175193
Issue No: Vol. 15, No. 7 (2023)
