BOUNDARY-LAYER FLOW AND HEAT-TRANSFER IN SATURATED AND UNSATURATED POROUS-MEDIA

This work analyses the process of forced heat transfer in the boundary layer formed over a flat plat embedded in a saturated and unsaturated porous medium, for the general case in which the viscosity of the flu id depends on temperature. The same problem is solved for the case of unsaturated flow in which a liquid flows through a porous medium in th e presence of a stagnant gas phase with uniform pressure. The effects of inertia and thermal dispersion are included in the formulation. Loc al thermal equilibrium among the phases is assumed to hold. In saturat ed flow, the results show that, at low and moderate Reynolds numbers, the viscosity variation affects to a significant extent the velocity a nd temperature profiles within the boundary layer, as well as the heat transfer rates at the wall. In unsaturated flow, it is shown that vis cosity variations induce a saturation profile within the porous medium . Sample calculations are performed for the flow of water through a pa cked bed of spheres.