TRANSIENT CONDUCTION-RADIATION INTERACTION IN A PLANAR PACKED BED WITH VARIABLE POROSITY

Abstract

Radiation combined with conduction in a planar packed bed of opaque and diffuse-gray spheres is investigated numerically. Both constant and variable porosity distributions are considered. Kamiuto's correlated scattering theory as well as Kaviany's scaling factor are used to study the effect of dependent scattering. The discrete transfer method is used to solve the radiative part of the energy equation, and Euler's implicit finite-difference scheme is used to solve the energy equation. Effects of effective thermal conductivity, bed depth-to-particle diameter ratio, scaled scattering albedo, and conduction-radiation parameter are studied for both steady and transient cases. These parameters have been found to have significant effects on total effective thermal conductivity, temperature, and radiative and conductive heat flux distributions.