Begell House Inc.
Computational Thermal Sciences: An International Journal
CTS
1940-2503
10
5
2018
A SPECTRAL RELAXATION APPROACH FOR DIFFUSION THERMO EFFECT ON TANGENT HYPERBOLIC FLUID PAST A STRETCHING SURFACE IN THE PRESENCE OF CHEMICAL REACTION AND CONVECTIVE BOUNDARY CONDITION
389-403
10.1615/ComputThermalScien.2018019965
Kotha
Gangadhar
Department of Mathematics, Acharya Nagarjuna University Ongole Campus, Ongole, A.P., India
Ch. Suresh
Kumar
Department of Mathematics, T.R.R. Government Degree College, Kandukur, A.P., India
T. Ranga
Rao
Department of Mathematics, SVKP College, Markapur, A.P., India
SRM
SOR
tangent hyperbolic fluid
diffusion thermo
convective condition
In this study, a numerical investigation has been carried out to discuss the steady, two-dimensional flow of heat and mass transfer of tangent hyperbolic fluid with diffusion thermo in the presence of chemical reaction and convective surface boundary condition. The flow is induced by a stretching surface. The anticipated technique is an efficient numerical algorithm with assured convergence that serves as an alternative to general numerical methods for solving nonlinear boundary value problems. We demonstrate that the convergence rate of the spectral relaxation method is significantly improved by using the method in conjunction with the successive overrelaxation method. Validation of the results was achieved by comparison with limiting cases from previous studies in the literature. The results are presented graphically and discussed for various resulting parameters. Wessenberg number increases the thickness of the fluid, so velocity profiles decrease with an increase in We. Diffusion thermo effect significantly increases the thermal boundary layer thickness. Both local Nusselt numbers and local Sherwood numbers give the same behavior for the Weissenberg number.
EFFECTS OF INSERTED POROUS SQUARE CYLINDER ON HEAT- AND MASS-TRANSFER ENHANCEMENT IN A CHANNEL
405-420
10.1615/ComputThermalScien.2018022498
Hamza
Mahdhaoui
Laboratoire de Mathématiques et Physique LAMPS, Université de Perpignan via Domitia, 52
Avenue Paul Alduy, 66860 Perpignan Cedex 9, France; Laboratoire d'Energétique et Transferts Thermique et Massique, Faculté des Sciences de
Bizerte, Bizerte, 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
blockage ratio
porous square cylinder
single-domain approach
evaporation
liquid film
heat and mass transfers
We numerically investigate the effects of an inserted square porous cylinder in a horizontal channel on flow structure
and heat and mass transfer. Channel walls have a thin liquid water film and are heated with a constant heat flux density. Several blockage ratio (β) and gap distances (γ) between cylinder and channel wall are considered for study of geometric effects on heat and mass transfer. We perform a comparison between two configurations (with and without porous square cylinder) to highlight the effect of the addition. To achieve this, we solve the classical equations of forced convection and the Darcy−Brinkman−Forchheimer model. Our investigation finds an improvement in heat and mass transfer with the presence of porous cylinder. This improvement is greater with a decrease in Darcy number (Da) and when the obstacle is placed in the middle of the channel. The Sherwood number, which characterizes mass transport, is correlated by a relationship with Reynolds number and ratio blockage. We provide some design guidelines related to Da, β, and γ that can be used in an engineering environment.
COMPUTATIONAL FLUID DYNAMICAL ANALYSIS OF NEW OBSTACLE DESIGN AND ITS IMPACT ON THE HEAT TRANSFER ENHANCEMENT IN A SPECIFIC TYPE OF AIR FLOW GEOMETRY
421-447
10.1615/ComputThermalScien.2018024416
Younes
Menni
Unite of Research on Materials and Renewable Energies - URMER - Department of Physics,
Faculty of Sciences, Abou Bekr Belkaid University, BP 119-13000-Tlemcen, Algeria
Ahmed
Azzi
Unit of Research on Materials and Renewable Energies – URMER, Abou Bekr Belkaid
University, BP 119-13000-Tlemcen, Algeria; Department of Mechanical Engineering, Faculty of Technology, Abou Bekr Belkaid University,
BP 230-13000-Tlemcen, Algeria
Faouzi
Didi
Unit of Research on Materials and Renewable Energies, Abou Bekr Belkaid University, BP
119-13000 Tlemcen, Algeria
Souad
Harmand
Thermique Ecoulement Mécanique MatériauxMise en Forme Production - TEMPO - Université de Valenciennes et du Hainaut Cambrésis, BP 59313 Valenciennes CEDEX 9, France
computational fluid dynamics
forced convection
heat exchangers
solar air collectors
The present work focuses on the study of an interesting topic from different points of view, that is, theoretical, practical,
and numerical modeling. This study aims to improve the heat transfer within thermal devices like heat exchangers, solar air collectors, and other electronic equipment; these thermal devices play a major role in the industry these days. This work consists of a computational fluid dynamical analysis of a turbulent forced-convection constant property Newtonian fluid flow, in the presence of two differently shaped solid-type obstacles, that is, flat rectangular and V-upstream
shaped, arranged in an overlapping manner, in a horizontal two-dimensional pipe of rectangular section. The effects of obstacle sizes and flow rates are analyzed. The Reynolds averaged Navier−Stokes equations with the standard k-ε turbulence model and the energy equation governing the problem are solved numerically by the finite volume method using the commercial CFD software FLUENT. The results are shown in terms of streamlines, mean velocity field, dimensionless axial velocity profiles, dynamic pressure, turbulent kinetic energy, turbulent intensity, fluid temperature, dimensionless temperature profiles, skin friction coefficients, local and average Nusselt numbers, and thermal enhancement factors.
THERMOMECHANICAL ANALYSIS OF THE RESISTANCE SPOT-WELDING PROCESS
449-455
10.1615/ComputThermalScien.2018020490
Habib
Lebbal
Faculté de Génie Mécanique, Université des Sciences et de la Technologie d'Oran - Mohamed
Boudiaf, U.S.T.O.-MB, BP 1505, El M'naouer Oran, Algérie
Lahouari
Boukhris
Laboratoire de Recherche en Technologie de Fabrication Mécanique (LaRTFM), Ecole Nationale Polytechnique M.A. (ENPO), 31000 Oran, Algérie;
Département de Génie Mécanique, Faculté de Génie Mécanique, Université des Sciences et de la Technologie d'Oran USTO-MB BP 1505 El-M'Naouer 31000 Oran, Algérie
Habib
Berrekia
Faculté de Génie Mécanique, Université des Sciences et de la Technologie d'Oran - Mohamed
Boudiaf, U.S.T.O.-MB, BP 1505, El M'naouer Oran, Algérie
Abdelkader
Ziadi
CTR University of AinTemouchent, Algeria
resistance spot welding
finite-element analysis
temperature distribution
principal residual stress
Resistance spot welding (RSW) is the process of joining two or more metal sheets by fusion at discrete spots at the sheet interface. Resistance to current flow through the metal sheets generates heat. Temperature rises at the sheet interface until the plastic point of the metal is reached, the metal begins to fuse, and a nugget is formed. Current is then switched off and the nugget is allowed to cool down slowly to solidify under pressure. In this article, an axisymmetric contact finite element analysis model of RSW was developed using commercial finite element code, namely ANSYS. A two-dimensional axisymmetric model was used to simulate the thermoelectromechanical coupling of the process to determine temperature distribution and different residual stresses in the contact electrode/sheet and sheet/sheet during the RSW process.
MHD FLOW INSIDE A STRETCHING/SHRINKING CONVERGENT/DIVERGENT CHANNEL WITH HEAT GENERATION/ABSORPTION AND VISCOUS-OHMIC DISSIPATION UTILIZING CU−WATER NANOFLUID
457-471
10.1615/ComputThermalScien.2018020807
Alok Kumar
Pandey
Department of Mathematics, Graphic Era Deemed to be University, Dehradun, 248002,
Uttarakhand, India
Manoj
Kumar
Department of Mathematics, Statistics, and Computer Science, G. B. Pant University of
Agriculture and Technology, Pantnagar, Uttarakhand 263145, India
heat generation/absorption
nanofluid
Ohmic heating
stretchable/shrinkable channel
viscous dissipation
The goal of the present study is to analyze the magnetohydrodynamic flow of Cu−water nanofluid between two stretchable/shrinking channels due to the effects of heat generation/absorption, viscous dissipation, and Ohmic heating. The model of thermal conductivity and dynamic viscosity is based on the spherical shape of nanoparticles. The numerical
method Runge−Kutta−Fehlberg fourth- to fifth-order scheme has been employed with a shooting scheme to solve
the transformed ordinary differential equations. The numerical solution of several dominant parameters, that is, heat
generation/absorption parameter, magnetic field parameter, and Eckert number, are obtained. The results signify that velocity profiles of stretching divergent channels decrease with a boost in Hartmann number, while for the same case, temperature curves constantly enhance. The shear stress rate is augmented with Hartmann number for stretching convergent/divergent channels. An admirable agreement has been noticed on comparing present results with earlier studies.
PERFORMANCE AND ECONOMICS OF A SOLAR DESICCANT AIR CONDITIONING SYSTEM FOR COOLING AN INSULATED GREENHOUSE IN TUNISIA
473-491
10.1615/ComputThermalScien.2018020247
Amel
Rjibi
Research and Technology Center of Energy, Thermal Processes Laboratory, Hammam Lif, B.P.
95, 2050 Tunis, Tunisia
Sami
Kooli
Research and Technology Center of Energy, Thermal Processes Laboratory, Hammam Lif, B.P.
95, 2050 Tunis, Tunisia
Ridha
Chargui
Research and Technology Center of Energy, Thermal Processes Laboratory, Hammam Lif, B.P.
95, 2050 Tunis, Tunisia
Amen Allah
Guisani
Research and Technology Center of Energy, Thermal Processes Laboratory, Hammam Lif, B.P.
95, 2050 Tunis, Tunisia
DEC system
cooling
greenhouse
TRNSYS
simulation
This work highlights the cooling potential of a desiccant evaporative cooling (DEC) cycle for an insulated greenhouse
with a surface area of 300 m2. DEC is assimilated in a closed loop that is comprised of several greenhouse components, including a flat plate collector, desiccant wheel, heat exchanger, and evaporative coolers. The system cools and dehumidifies the air without using conventional harmful refrigerants. We insert our experimental data in to a numerical
model based on a transient system simulation program and analyze the feasibility of the solar DEC system. Our results
show that the best performance of the system (coefficient of performance COPel = 14; COPth = 0.94) is obtained using 60°C regeneration temperature and a supply/regeneration flow ratio of 0.2. The system reduces inside temperature by 6°C in comparison to a conventional system, and the increased electricity permits an increase of cost for 25 years as viewing time.