A NUMERICAL INVESTIGATION OF MIXED CONVECTION IN A VERTICAL POROUS ANNULUS
The purpose of the present study-was to establish a model for flow, heat transfer and thermal dispersion in porous media by comparing analytical results with experimental data and to determine the effect of variable properties, buoyancy, particle diameter and fluid pressure on the flow and heat transfer. The inner wall of the annulus was maintained at a constant heat flux while the outer wall was adiabatic. Water was used as the working fluid in a bed of glass particles. A two-dimensional, finite-difference method was used to numerically study the mixed convection. Three different water pressures were used: O.lMPa, 17MPa and 25MPa. It was found that the effect of thermal dispersion must be considered. At super-critical pressures (25MPa), variable properties have significant influence on the heat transfer.