Influence of thermal radiation from solid phase upon the local thermal non-equilibrium condition in a porous medium
Present work investigates numerically the effect of thermal radiation from solid phase on the fluid and solid temperature fields inside a porous medium through investigating forced convection heat transfer process within a pipe filled with a porous media. A local thermal non-equilibrium (LTNE), two-equation model is employed to represent the energy transport for the solid and fluid phases. The radiative heat transfer equation is solved by discrete ordinate method (DOM) to compute the radiative heat flux in the porous medium. The effects of radiative heat transfer from solid phase on the temperature profiles of the solid and fluid phases are analyzed under different parameters. These include porosity, fluid and solid internal heat generations, Darcy number, solid to solid thermal conductivity ratio and inertia parameter. The effects of radiative heat transfer on the temperature distributions and Nusselt numbers for the two phases are, then, examined by comparing the result obtained by application of models A and B. The results show that the radiative heat transfer plays a profound role in determining the solid and fluid temperature fields within the porous medium. It is found that the solid and fluid temperatures fields for a radiative case are substantially lower than those obtained for the corresponding non-radiative case. Further, the thermal radiation from the solid phase drives the temperature fields towards LTE condition.