Local thermal nonequilibrium effects in forced convection in a porous medium channel: a conjugate problem

Forced convection in a plane channel filled with a saturated porous medium, coupled with conduction in plane slabs bounding the channel, is investigated analytically on the basis of a two-temperature model allowing for local thermal nonequilibrium (LTNE). It is found that the effect of the finite thermal resistance due to the slabs is to reduce both the heat transfer to the porous medium and the degree of LTNE. An increase in value of the Peclet number leads to a decrease in the rate of exponential decay in the downstream direction but does not affect the value of a suitably defined Nusselt number. The dependence of the Nusselt number on a new solid-fluid heat exchange parameter, the solid/fluid thermal conductivity ratio, and the porosity, is investigated. The general two-temperature formulation of the thermal boundary conditions is discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.