THEORETICAL-STUDY OF COMBINED CONDUCTIVE, CONVECTIVE AND RADIATIVE HEAT-TRANSFER BETWEEN PLATES AND PACKED-BEDS

The forced convective heat transfer near a wall or a plate immersed in a packed bed at high temperature is considered in this paper. The non -Darcian effects are considered for the hydrodynamics and heat transfe r and dependent scattering theory are taken into account for the radia tion transfer. The discrete-ordinate method is used to solve the equat ion for radiation intensity. It is found from the numerical prediction s that radiative heat transfer rate increases with a decrease of the c onvection-radiation parameter (B0) or conduction-radiation parameter ( N) and an increase of the Reynolds number. The effect of radiation on conduction-convection is determined by the sign of the net radiation a bsorbed by the particles. The radiation properties of the plate and th e bed, as well as the direction of heat flux, have obvious influence o n heat transfer in packed beds at high temperature.