Numerical investigation of forced convection heat transfer in porous mediausing a thermal non-equilibrium model

In the present paper, the effects of viscous dissipation, the boundary cond ition assumptions, thermal dispersion, particle diameters and the variable properties of oil on convection heat transfer are analyzed using a numerica l model including thermal nonequilibrium assumption. The results, which are compared with experimental data, show that the convection heat transfer in porous media can be predicted numerically using the thermal non-equilibriu m model with the ideal constant wall heat flux boundary condition. Viscous dissipation weakens the convection heat transfer from the fluid to the wall in the porous media. However, under practical conditions the influence of viscous dissipation on the convection heat transfer is small. The fluid tem perature in the bottom part of the channel is higher than in the core regio n of the channel when the lower plate is adiabatic due to the effect of vis cous dissipation. The variation of the thermal physical properties of oil h as a profound influence on the convection heat transfer coefficient, which increases as the heat Bur increases. When the upper and lower plates are he ated with the same heat Aux, the convection heat transfer coefficient on th e upper plate surface is higher than when one side is heated and the other is insulated. However, the differences caused by these two kinds of boundar y conditions in porous media are less than that in an empty channel. (C) 20 01 Elsevier Science Inc. All rights reserved.