Microwave heating of a porous medium with a nonuniform porosity is numerically investigated based on a proposed numerical model. A two-dimensional variation of porosity of the medium is considered. The generalized non-Darcian model developed takes into account the presence of a solid drag and the inertial effect. The transient Maxwell’s equations are solved by using the finite difference time domain method to describe the electromagnetic field in the waveguide and medium. The temperature profile and velocity field within a medium are determined by solution of the momentum, energy, and Maxwell’s equations. The coupled nonlinear set of these equations is solved using the SIMPLE algorithm. In this work, a detailed parametric study is conducted on heat transport inside a rectangular enclosure filled with a saturated porous medium of constant or variable porosity. The numerical results agree well with the experimental data. Variations in porosity significantly affect the microwave heating process as well as the convective flow pattern driven by microwave energy.
Issue Section:
Natural and Mixed Convection
1.
Wei
, C. K.
, Davis
, H. T.
, Davis
, E. A.
, and Gordon
, J.
, 1985, “Heat and Mass Transfer in Water-Laden Sandstone: Microwave Heating
,” AIChE J.
0001-1541, 31
(5
), pp. 842
–848
.2.
Ni
, H.
, Datta
, A. K.
, and Torrance
, K. E.
, 1999, “Moisture Transport in Intensive Microwave Heating of Biomaterials: Porous Media Model
,” Int. J. Heat Mass Transfer
0017-9310, 42
, pp. 1501
–1512
.3.
Feng
, H.
, Tang
, J.
, Cavalieri
, R. P.
, and Plumb
, O. A.
, 2001, “Heat and Mass Transport in Microwave Drying of Porous Materials in a Spouted Bed
,” AIChE J.
0001-1541, 47
, pp. 1499
–1512
.4.
Ratanadecho
, P.
, Aoki
, K.
, and Akahori
, M.
, 2002, “Influence of Irradiation Time, Particle Sizes, and Initial Moisture Content During Microwave Drying of Multi-Layered Capillary Porous Materials
,” ASME J. Heat Transfer
0022-1481, 124
(1
), pp. 151
–161
.5.
Dinčov
, D. D.
, Parrot
, K. A.
, and Pericleous
, K. A.
, 2004, “Heat and Mass Transfer in Two-Phase Porous Materials Under Intensive Microwave Heating
,” J. Food Eng.
, 65
, pp. 403
–412
.6.
Rattanadecho
, P.
, 2006, “The Simulation of Microwave Heating of Wood Using a Rectangular Wave Guide: Influence of Frequency and Sample Size
,” Chem. Eng. Sci.
0009-2509, 61
, pp. 4798
–4811
.7.
Ratanadecho
, P.
, Aoki
, K.
, and Akahori
, M.
, 2002, “A Numerical and Experimental Investigation of Modelling of Microwave Heating for Liquid Layers Using a Rectangular Wave Guide (Effects of Natural Convection and Dielectric Properties)
,” Appl. Math. Model.
0307-904X, 26
, pp. 449
–472
.8.
Cha-um
, W.
, Rattanadecho
, P.
, and Pakdee
, W.
, 2009, “Experimental Analysis of Microwave Heating of Dielectric Materials Using a Rectangular Wave Guide (MODE: TE10) (Case Study: Water Layer and Saturated Porous Medium)
,” Exp. Therm. Fluid Sci.
0894-1777, 33
(3
), pp. 472
–481
.9.
Ayappa
, K. G.
, and Brandon
, S.
, 1994, “Microwave Driven Convection in a Square Cavity
,” AIChE J.
0001-1541, 40
(7
), pp. 1268
–1272
.10.
Franca
, A. S.
, and Haghighi
, K.
, 1996, “Adaptive Finite Element Analysis of Microwave Driven Convection
,” Int. Commun. Heat Mass Transfer
0735-1933, 23
(2
), pp. 177
–186
.11.
Chatterjee
, S.
, Basak
, T.
, and Das
, S. K.
, 2007, “Microwave Driven Convection in a Rotating Cylindrical Cavity: A Numerical Study
,” J. Food Eng.
, 79
, pp. 1269
–1279
.12.
Liu
, S.
, and Masliyah
, J. H.
, 1996, “Single Fluid Flow in Porous Media
,” Chem. Eng. Commun.
0098-6445, 148
, pp. 653
–732
.13.
Benenati
, R. F.
, and Brosilow
, C. B.
, 1962, “Void Fraction Distribution in Pack Beds
,” AIChE J.
0001-1541, 8
, pp. 359
–361
.14.
Vafai
, K.
, 1984, “Convective Flow and Heat Transfer in Variable-Porosity Media
,” J. Fluid Mech.
0022-1120, 147
, pp. 233
–259
.15.
Amiri
, A.
, and Vafai
, K.
, 1994, “Analysis of Dispersion Effects and Non-Thermal Equilibrium, Non-Darcian, Variable Porosity Incompressible Flow Through Porous Media
,” Int. J. Heat Mass Transfer
0017-9310, 37
(6
), pp. 939
–954
.16.
Khaled
, A. -R. A.
, and Chamkha
, A. J.
, 2001, “Variable Porosity and Thermal Dispersion Effects on Coupled Heat and Mass Transfer by Natural Convection From a Surface Embedded in a Non-Metallic Porous Medium
,” Int. J. Numer. Methods Heat Fluid Flow
0961-5539, 11
(5
), pp. 413
–429
.17.
Hsiao
, S. -W.
, Cheng
, P.
, and Chen
, C. -K.
, 1992, “Non-Uniform Porosity and Thermal Dispersion Effects on Natural Convection About a Heated Horizontal Cylinder in an Enclosed Porous Medium
,” Int. J. Heat Mass Transfer
0017-9310, 35
(12
), pp. 3407
–3418
.18.
Sakamoto
, H.
, and Kulacki
, F. A.
, 2008, “Effective Thermal Diffusivity of Porous Media in the Wall Vicinity
,” ASME J. Heat Transfer
0022-1481, 130
(2
), p. 022601
.19.
Vafai
, K.
, 1986, “Analysis of the Channeling Effect in Variable Porosity Media
,” ASME J. Energy Resour. Technol.
0195-0738, 108
, pp. 131
–139
.20.
Hunt
, M. L.
, and Tien
, C. L.
, 1998, “Non-Darcian Convection in Cylindrical Packed Beds
,” ASME J. Heat Transfer
0022-1481, 110
, pp. 2523
–2532
.21.
Poulikakos
, D.
, and Renken
, K.
, 1987, “Forced Convection in a Channel Filled With Porous Medium, Including the Effects of Flow Inertia, Variable Porosity and Brinkman Friction
,” ASME J. Heat Transfer
0022-1481, 109
, pp. 880
–888
.22.
Chai
, Z.
, and Guo
, Z.
, 2007, “Study of Electro-Osmotic Flows in Microchannels Packed With Variable Porosity Media via Lattice Boltzmann Method
,” J. Appl. Phys.
0021-8979, 101
, p. 104913
.23.
Akbal
, S.
, and Baytas
, F.
, 2008, “Effects of Non-Uniform Porosity on Double Diffusive Natural Convection in a Porous Cavity With Partially Permeable Wall
,” Int. J. Therm. Sci.
1290-0729, 47
(7
), pp. 875
–885
.24.
Ratanadecho
, P.
, Aoki
, K.
, and Akahori
, M.
, 2001, “Experimental and Numerical Study of Microwave Drying in Unsaturated Porous Material
,” Int. Commun. Heat Mass Transfer
0735-1933, 28
(5
), pp. 605
–616
.25.
El-Refaee
, M. M.
, Elsayed
, M. M.
, Al-Najem
, N. M.
, and Noor
, A. A.
, 1998, “Natural Convection in Partially Cooled Tilted Cavities
,” Int. J. Numer. Methods Fluids
0271-2091, 28
, pp. 477
–499
.26.
Nield
, D. A.
, and Bejan
, A.
, 1999, Convection in Porous Media
, Springer
, New York
.27.
Al-Amiri
, A. A.
, 2002, “Natural Convection in Porous Enclosures: The Application of the Two-Energy Equation Model
,” Numer. Heat Transfer, Part A
1040-7782, 41
, pp. 817
–834
.28.
Marafie
, A.
, and Vafai
, K.
, 2001, “Analysis of Non-Darcian Effects on Temperature Differentials in Porous Media
,” Int. J. Heat Mass Transfer
0017-9310, 44
, pp. 4401
–4411
.29.
Nithiarasu
, P.
, Seetharamu
, K. N.
, and Sundararajan
, T.
, 1997, “Natural Convective Heat Transfer in a Fluid Saturated Variable Porosity Medium
,” Int. J. Heat Mass Transfer
0017-9310, 40
, pp. 3955
–3967
.30.
Chamkha
, A. J.
, Issa
, C.
, and Khanafer
, K.
, 2002, “Natural Convection From an Inclined Plate Embedded in a Variable Porosity Porous Medium Due to Solar Radiation
,” Int. J. Therm. Sci.
1290-0729, 41
, pp. 73
–81
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