EVALUATION OF TWO RADIATION MODELS IN CFD FIRE MODELING

Thermal radiation, although considered an important mode of heat transfer in high temperature conditions, often is neglected in fire modeling, mainly because of the complex physics involved. This study provides modelers with guidance on the engineering treatment of radiation transfer. Two widely used radiation models, the discrete transfer and the six-flux models, are reviewed and their performance is assessed in a benchmark fire case. The models are compared in terms of computational efficiency, ease of application, and predictive accuracy, and their range of validity is delineated, for single compartment fire cases. The results demonstrate that the simple six-flux model suffices for small compartment fires, up to 100 kW. For higher heat release rates, where the six-flux model breaks down, the discrete transfer provides sufficient accuracy, under certain conditions.