FLUID FLOW AND CONVECTIVE HEAT TRANSFER IN A VERTICAL POROUS ANNULUS

Abstract

This article presents a numerical study of upward fluid flow and the corresponding convective heat transfer in a vertical porous annulus. The study investigated the effects of the inertia term, thermal dispersion, variable porosity, variable properties, buoyancy, particle diameter, and fluid pressure on the flow and heat transfer. The heat transfer augmentation produced by the porous matrix was also analyzed. It was found that for the conditions studied, the effect of thermal dispersion and variable porosity had to be considered. For Re_e ≥ 5, the flow inertia had nonnegligible influence on the flow field and local heat transfer coefficient near the inlet (x / L ≤ 0.02). When Re_e ≥ 400, the flow inertia significantly influenced the overall friction factor in the vertical porous annulus. The porous medium greatly enhanced the heat transfer coefficient and also sharply increased the friction resistance. At supercritical pressures (25 Mpa), variable properties significantly influenced the heat transfer.