Numerical comparison of radiative heat transfer models

A numerical comparison is presented for two mathematical models of radiative heat transfer, a direct method using the Stefan-Boltzmann law and a two step method using flux models (called the radiosity approach). The flux model equations are solved by the successive approximation technique and Hottel's matrix inversion technique, and a rectangular parallelopiped is assumed for the enclosure in order to focus on the computational aspects. The effects of the participating medium, the number of zones, and the boundary conditions are investigated, and the effect of the relaxation parameter is examined as an aid for the improvement of convergence. It is concluded that the successive approximation technique, using a relaxation parameter for solving model equations, obtained from the radiosity approach is the best method.