Begell House Inc.
Computational Thermal Sciences: An International Journal
CTS
1940-2503
10
6
2018
FINITE ELEMENT LEGENDRE WAVELET GALERKIN APPROACH IN INVESTIGATION OF NON-FOURIER'S AND NON-FICK'S EFFECTS ON HEAT AND MASS TRANSFER DURING DRYING OF FOODS
493-519
10.1615/ComputThermalScien.2018019984
Subrahmanayam
Upadhyay
DST-CIMS, Banaras Hindu University, Varanasi-221005, Uttar Pradesh, India
Kabindra Nath
Rai
Department of Mathematical Sciences, Indian Institute of Technology (BHU), Varanasi- 22005, Uttar Pradesh, India; DST-CIMS, Banaras Hindu University,Varanasi-22005, Uttar Pradesh, India
SPL model
FELWGM
system of Sylvester equations
effect of parameters on food drying
In this article, we developed a single phase lag model (SPL) on heat mass transfer within foods of different geometrical configurations such as slab, cylinder, or sphere, under the most generalized boundary conditions in application of
drying of foods. The present model is a generalization of diffusion model, Luikov's model, and Chang and Weng's, and
Win-Jin et al.'s model. The finite element Legendre wavelet Galerkin method (FELWGM) is used in the solution. The
discretization in space and then application of Legendre wavelet Galerkin method converts the problem into a coupled
system of Sylvester equations. The use of the Kronecker product of matrices and then application of the Gauss elimination method provides a solution. Stability analysis of the present method is provided. In the absence of relaxation time, the present model is Chang and Weng's and Win-Jin et al.'s model. In this case, the solution obtained by the present method is approximately the same as that obtained by Win-Jin et al. Again, in a particular case, the solution obtained by the present method is compared with an exact analytical solution obtained using Laplace transform technique and are exactly the same. The whole analysis is done in nondimensional form. The effect of shape (slab, cylinder, or sphere) in the process of heat and mass transfer is discussed in detail. The slab shape of foods takes higher time than the spherical shape of foods and less time than the cylindrical shape of food in drying. Furthermore, the effects of relaxation time
parameter (η0, η1), Luikov number (Lu), Kirpichev number (Kiq, Kim), Biot number (Biq, Bim), Kossovich number
(Ko), Predvoditelev number (Pd1, Pd2), and Possnov number (Pn) on heat and mass transfer are discussed in detail
for the slab shape of foods.
MIXED CONVECTION OF NANOFLUID OVER A BACKWARD FACING STEP UNDER THE EFFECTS OF A TRIANGULAR OBSTACLE AND INCLINED MAGNETIC FIELD
521-543
10.1615/ComputThermalScien.2018020085
Fatih
Selimefendigil
Mechanical Engineering Department, Celal Bayar University, Manisa, 45140, Turkey
Hakan F.
Öztop
Department of Mechanical Engineering, Technology Faculty, Firat University, Elazig, Turkey; Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University,
P.O. Box 40844, Jeddah 21511, Saudi Arabia
mixed convection
magneto hydrodynamics
nanofluid
obstacle
artificial neural networks
In this study, laminar mixed convection of CuO–water nanofluid over a backward facing step with the presence of a
triangular obstacle and under the effect of magnetic field was numerically investigated. Finite volume method was used
to solve the governing equations for the range of parameters: Richardson number (between 0.01 and 100), Hartmann number (between 0 and 50), nanoparticle volume fraction (between 0 and 0.04), and horizontal location of the triangular obstacle (between 0.5H and 2H). It was observed that average heat transfer is a decreasing function of Richardson number and an increasing function of nanoparticle volume fraction. The dependence of average heat transfer on the magnetic field parameters shows a resonant-type behavior. The obstacle affects the local Nusselt number distribution near the step especially for lower values of Richardson number and Hartmann number. Artificial neural networks were used to develop models that can be used instead of high-fidelity computational fluid dynamics simulations for fast and accurate thermal performance predictions of the considered system.
NUMERICAL STUDY ON MIXED CONVECTION IN A POWER-LAW FLUID SATURATED POROUS MEDIUM WITH VARIABLE PROPERTIES AND THERMOPHORESIS EFFECTS VIA LIE SCALING GROUP TRANSFORMATIONS
545-555
10.1615/ComputThermalScien.2018016882
Janapatla
Pranitha
Department of Mathematics, National Institute of Technology, Warangal-506004, India
G. Venkata
Suman
Department of Mathematics, National Institute of Technology, Warangal-506004, India
D.
Srinivasacharya
Department of Mathematics, National Institute of Technology, Warangal-506004,
India
mixed convection
thermophoresis
variable viscosity
thermal conductivity
power-law fluid
Lie scaling group transformations
A numerical investigation has been carried out on two-dimensional steady state mixed-convection heat and mass
transfer on a vertical plate in a power-law fluid saturated Darcy porous medium. The effects of variable viscosity,
thermal conductivity, and thermophoresis are analyzed. The governing equations (continuity, momentum, energy,
and concentration equations) are transformed into nonlinear ordinary differential equations by using the Lie scaling
group transformations. These nonlinear ordinary differential equations are solved numerically using the shooting
technique. The results are compared with previously published work and are found to be in good agreement. The
results of variable viscosity, thermal conductivity, and thermophoresis parameters on the nondimensional velocity,
temperature, and concentration profiles for pseudoplastic, Newtonian, and dilatant fluids are displayed graphically.
Heat and mass transfer coefficient results are displayed in tabular form.
RAYLEIGH WAVES IN A THERMO-ORTHOTROPIC MEDIUM: A DYNAMIC ANALYSIS
557-574
10.1615/ComputThermalScien.2018018842
Soumen
Shaw
Indian Institute of Engineering Science and Technology,Shibpur
Siddhartha
Biswas
Department of Mathematics University of North Bengal Darjeeling, India
Basudeb
Mukhopadhyay
Department of Mathematics, IIEST, Shibpur Botanic Garden, Howrah, West Bengal, 711103,
India
Rayleigh waves
orthotropic material
three-phase-lag model
two-temperature theory
normal-mode analysis
frequency equation
The present article deals with the characteristics of Rayleigh wave propagation in thermo- orthotropic half-space.
This thermodynamical analysis is carried out in the context of a three-phase-lag thermoelasticity model with two-temperature theory. A more general form of the dispersion equation is derived. The path of surface particles is found
to be elliptical during the propagation of Rayleigh waves in a thermoelastic-orthotropic medium. The effect of phase
lags on the various components of Rayleigh waves are demonstrated graphically. Finally, it is found that the results obtained in the present problem agree with the results obtained by various other researchers.
NUMERICAL INVESTIGATION OF HEAT AND MASS TRANSFER WITH CONDENSATION IN A GYPSUM BOARD USING THE LATTICE BOLTZMANN METHOD
575-592
10.1615/ComputThermalScien.2018019998
Kaouther
Zannouni
Laboratory of Thermal and Energy Systems Studies, National School of Engineers, Monastir
University, Monastir, Tunisia
Hacen
Dhahri
Laboratory of Thermal and Energy Systems Studies, National School of Engineers, Monastir
University, Monastir, Tunisia
Abdallah
Mhimid
Laboratory of Thermal and Energetic Systems Studies (LESTE) at the National School of
Engineering of Monastir, 5019 Ibn Eljazzar Street, University of Monastir
condensation
heat and mass transfer
gypsum board
LBM
Heat and mass transfer with condensation in a gypsum board based on a diffusive model is investigated. The upper
face of the plate represents the permeable interface. Both the vertical and low sides of the porous media are supposed
to be adiabatic and impermeable surfaces. The model for the energy transport is based on the local thermodynamic
equilibrium between the fluid and solid phases. The lattice Boltzmann method (LBM) is used to solve the differential
equation system. The obtained numerical results concerning themoisture content and the temperature within a gypsum
sample were discussed. A systematical investigation was conducted to explore the influence of different parameters on the processes, including the external temperature, the relative humidity, the diffusion coefficient, and the porosity of the gypsum sample on macroscopic fields.
INDEX VOLUME 10, 2018
593-598
10.1615/ComputThermalScien.v10.i6.60