Abstract
Numerical solutions were obtained by the relaxation method to the combined conduction and radiation heat transfer equation in the cubic (ε = o.476) and orthorhombic (ε=O.395) lattice models of spheres, respectively. The calculated results are shown in chart as ke/kf vs. ks/kf (=10-3104) with parameter of hrDp/ks (-0-1). Effective thermal conductivities were experimentally determined and found in good agreement with the theory. The formula for radiation heat transfer coefficient hr is also presented.