Begell House Inc.
Computational Thermal Sciences: An International Journal
CTS
1940-2503
9
5
2017
PREDICTION OF THERMOSOLUTAL CONVECTION IN A POROUS MEDIUM WITH SORET-DUFOUR AND CHEMICAL REACTION EFFECTS
383-393
Mohamed
El Haroui
University of Sidi Mohamed Ben Abdellah, Polydisciplinary Faculty of Taza, LSI, Team of
Numerical Modeling in Mechanics Applied (MNMA), BP.1223, Taza, Morocco
M.
Sriti
University of Sidi Mohamed Ben Abdellah, Polydisciplinary Faculty of Taza, LSI, Team of
Numerical Modeling in Mechanics Applied (MNMA), BP.1223, Taza, Morocco
Driss
Achemlal
University of Sidi Mohammed Ben Abdellah, Polydisciplinary Faculty of Taza
E.
Flilihi
University of Sidi Mohamed Ben Abdellah, Polydisciplinary Faculty of Taza, LSI, Team of
Numerical Modeling in Mechanics Applied (MNMA), BP.1223, Taza, Morocco
The thermosolutal free convection flow in a saturated porous medium past a vertical porous plate exposed to three
thermal states of the surface and a constant concentration is numerically analyzed in the presence of chemical reaction, uniform suction, or injection and Soret-Dufour effects. The mathematical model of the problem is reduced into a set of coupled nonlinear ordinary differential equations, using unique similarity transformations. The resulting equations are solved numerically by a computational code based on the fifth-order Runge-Kutta scheme along with the shooting iteration technique. A comparison to previously published work is performed, and the results were in excellent agreement. The obtained results are displayed graphically for various controlling parameters. It was found that the chemical reaction has a relevant effect on the concentration field. Also, the thermal state of the plate surface has an important effect on the temperature and concentration profiles as on the wall heat and mass transfer rates.
COMPUTATIONAL COMPLEXITY OF THE ALGORITHM FOR A 2D ADAPTIVE MESH REFINEMENT METHOD USING LID-DRIVEN CAVITY FLOWS
395-403
Zhenquan
Li
School of Computing and Mathematics, Charles Sturt University, Thurgoona, NSW2640, Australia
After successful accuracy and reliability verifications of the algorithm for a 2D adaptive mesh refinement method using
exact and numerical benchmark results, we consider the computational complexity of this algorithm using 2D steady
incompressible lid-driven cavity flows. The algorithm for the 2D adaptive mesh refinement method is proposed based
on the qualitative theory of differential equations. The adaptive mesh refinement method performs mesh refinement
based on the numerical solutions of Navier-Stokes equations solved by Navier2D, an open source vertex-centered finite
volume code that uses the median dual mesh to form the control volumes about each vertex. We show the comparisons of the computational complexities between the algorithm of the adaptive mesh refinement method twice and the algorithm
that uses uniform mesh with the same size of twice refined cells for Reynolds numbers 100, 1000, 2500. The adaptive
mesh refinement method can be applied to find the accurate numerical solutions of any mathematical models containing
continuity equations for incompressible fluid or steady-state fluid flows.
BUOYANCY-DRIVEN HEAT TRANSFER ENHANCEMENT IN A SINUSOIDALLY HEATED ENCLOSURE UTILIZING HYBRID NANOFLUID
405-421
Tahar
Tayebi
Faculty of Sciences and Technology, Mohamed El Bachir El Ibrahimi University, Bordj Bou
Arreridj, El-Anasser, 34030, Algeria; Energy Physics Laboratory, Department of Physics, Faculty of Science, Mentouri Brothers
Constantine University, 25000, Algeria
Ali J.
Chamkha
Department of Mechanical Engineering, Prince Sultan Endowment for Energy and
Environment, Prince Mohammad Bin Fahd University, Al-Khobar 31952, Kingdom of Saudi
Arabia; RAK Research and Innovation Center, American University of Ras Al Khaimah, United Arab Emirates, 10021
The purpose of this work is to study numerically heat transfer and fluid flow characteristics by natural convection in an enclosure filled with Al2O3/water nanofluid and Cu-Al2O3/water hybrid nanofluid including pure water. The left sidewall of the cavity is heated by a nonuniform surface temperature, while the right wall is kept isothermally cooled. The basic equations that govern the problem (continuity, momentum, and energy) are formulated in terms of the vorticity-stream function equations using the dimensionless form for two-dimensional, laminar and incompressible flow under steady-state conditions. Those equations are discretized via the finite volume method and solved by a FORTRAN computer program. The thermophysical properties of the nanofluid and the hybrid nanofluid are calculated in terms of the volume fraction of nanoparticles and combined nanoparticles. A numerical study is performed for an enclosure filled with regular water, Al2O3/water nanofluid, and Cu-Al2O3/water hybrid nanofluid for various volume fractions of nanoparticles and hybrid nanoparticles (0 ≤ φ ≤ 0.12) and Rayleigh number (103
≤ Ra ≤ 105). The results of the study are presented in the form of streamlines, isotherm contours, and distribution of the local and average Nusselt numbers on the heated wall. The main result we obtained is that the use of Cu-Al2O3/water hybrid nanofluid offers better thermal and dynamic performance compared to the similar Al2O3/water nanofluid.
HEAT AND MASS TRANSFERS BY NATURAL CONVECTION DURING WATER EVAPORATION IN A VERTICAL CHANNEL
423-445
Olfa
Mechergui
LAMPS, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan,
France; LETTM, Département de Physique, Faculté des Sciences de Tunis, Université de Tunis El
Manar, 1060 Tunis, Tunisie; Département de Physique, Faculté des Sciences de Bizerte, Université du 7 Novembre Carthage, 7021 Jarzouna, Tunisie
Xavier
Chesneau
Laboratoire de Mathématiques et Physique LAMPS, Université de Perpignan via Domitia, 52
Avenue Paul Alduy, 66860 Perpignan Cedex 9, France
Ali Hatem
Laatar
LETTM, Department of Physics, Faculty of Sciences of Tunis, Tunis El Manar University, 1060 Tunis, Tunisia; Department of Physics, Faculty of Sciences of Bizerte, University of the 7th November at Carthage, 7021 Jarzouna-Bizerte, Tunisia; Department of Physics, Faculty of Sciences of Tabuk, Tabuk University 71491, Saudi Arabia
This paper deals with a numerical study of coupled heat and mass transfer by natural convection during water evaporation
in a vertical or inclined channel. This channel is asymmetrically heated with a uniform heat flux. The unsteady
two-dimensional Navier-Stokes, energy, and species equations are integrated by a finite volume approach and then
solved using the projections method. The aim of this work is to conduct a detailed numerical study to analyze the
effects of physical parameters, such as flux density imposed at the wall, the relative humidity, the air temperature at the entrance of the channel, and the inclination angle effects. The numerical results, including the distributions of dimensionless axial velocity, temperature, and concentration distributions, Nusselt number as well as Sherwood number are presented.
MIXED CONVECTIVE HEAT TRANSFER OF IMMISCIBLE FLUIDS IN A VERTICAL CHANNEL WITH BOUNDARY CONDITIONS OF THE THIRD KIND
447-465
J. Prathap
Kumar
Department of Mathematics, Gulbarga University, Gulbarga, Karnataka, India
Jawali C.
Umavathi
Department of Mathematics, Gulbarga University, Kalaburgi-585106, Karnataka, India
Ali J.
Chamkha
Department of Mechanical Engineering, Prince Sultan Endowment for Energy and
Environment, Prince Mohammad Bin Fahd University, Al-Khobar 31952, Kingdom of Saudi
Arabia; RAK Research and Innovation Center, American University of Ras Al Khaimah, United Arab Emirates, 10021
Y.
Ramarao
Department of Mathematics, Gulbarga University, Gulbarga-585 106, Karnataka, India
The effect of viscous dissipation and boundary conditions of the third kind on fully developed mixed convection for the
laminar flow in a parallel plate vertical channel filled with two immiscible viscous fluids is studied analytically. The plate exchanges heat with an external fluid. Both conditions of equal and different reference temperatures of external fluid are considered. Separate solutions are matched at the interface using suitable matching conditions. First, the simple cases of the negligible Brinkman or negligible Grashof numbers are solved. Then, the combined effects of buoyancy forces and viscous dissipation are analyzed by the perturbation series method (PM), valid for small values of the perturbation parameter, and by the differential transform method (DTM), valid for all values of perturbation parameter. Numerical results are presented graphically for the distribution of velocity and temperature fields for varying physical parameters, such as the mixed convection parameter, perturbation parameter, viscosity ratio, width ratio, conductivity ratio, and Biot numbers. The effect of these parameters on the Nusselt number at the walls is also presented graphically. It is found that the mixed convection parameter and perturbation parameter enhance the flow field; whereas, the viscosity ratio, width ratio, and conductivity ratio suppress the flow field. It is also found that both PM and DTM solutions agree very well for small values of the perturbation parameter.
MHD MIXED BIOCONVECTION STAGNATION-POINT FLOW OF A NANOFLUID TOWARD STRETCHING SURFACES WITH VISCOUS DISSIPATION AND JOULE HEATING EFFECTS
467-481
Zehba A.
Raizah
Department of Mathematics, Faculty of Science for Girls, Abha, King Khalid University, Saudia
Arabia
This paper discusses the effects of viscous dissipation and Joule heating on the mixed convective flow of a nanofluid over a stretching surface in the presence of both nanoparticles and gyrotactic microorganisms. The nanofluid is represented by the model that includes both the effects of Brownian motion and thermophoresis. The flux of the nanoparticle volume fraction is equal to zero at the wall. Similarity transformations are used to reduce the original governing equations embodying the conservation of mass, momentum, thermal energy, nanoparticle volume fraction, and the conservation equation for microorganisms to a set of five ordinary differential equations. The obtained equations are solved numerically using an efficient, iterative, tri-diagonal, implicit finite difference method. It is found that the increase in the thermophoresis parameter and Eckert number has a positive effect on the local skin friction coefficient; however, its negative effect can be observed on the local density number of the motile microorganisms. Also, the rescaled nanoparticle volume fraction decreases as the Lewis number and Brownian motion increase.