An evaluation of discrete transfer and YIX radiation methods for complex participating media

Performance comparisons of the discrete transfer (DTM) and YIX methods for participating radiative heat transfer in complex geometries are presented. An efficient implementation of each method is employed, with minimal variation in the coding and optimisation strategies, so as to ensure that these comparisons are as bias-free as possible. In fact, both methods embody the same geometric representational scheme and search strategies for ray tracing. It is shown that there are strong similarities in the methodologies, particularly with regard to the integration of the incident radiative heat flux at surface points. However, DTM gains a significant performance advantage in solving for the medium heat source and irradiation terms concurrently with the surface integrations. With regard to their accuracy there is little distinction between the two methods as applied to optically thin media, but with increasing optical thickness the accuracy of YIX, and DTM when scattering is present, solutions is found to deteriorate severely: explanations are given and recommendations are made.