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

Abstract

Abstract In the present paper, the effects of viscous dissipation, the boundary condition assumptions, thermal dispersion, particle diameters and the variable properties of oil on convection heat transfer are analyzed using a numerical model including thermal non-equilibrium 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-equilibrium 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 temperature in the bottom part of the channel is higher than in the core region of the channel when the lower plate is adiabatic due to the effect of viscous dissipation. The variation of the thermal physical properties of oil has a profound influence on the convection heat transfer coefficient, which increases as the heat flux increases. When the upper and lower plates are heated with the same heat flux, the convection heat transfer coefficient on the 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 boundary conditions in porous media are less than that in an empty channel.