UC Santa Barbara

The formulation of a multiple absorption coefficient zonal method (MACZM) is presented. The concept of generic exchange factors (GEF) is introduced. Utilizing the GEF concept, the MACZM is shown to be effective in simulating accurately the physics of radiative exchange in multidimensional, inhomogeneous, nongray media. The method can be applied directly to a fine-grid finite-difference or finite-element computation. It is thus suitable for direction implementation in an existing computational fluid dynamics (CFD) code for analysis of radiative heat transfer in practical engineering systems. The feasibility of the method is demonstrated by calculating the radiative exchange between a high-temperature (similar to 3,000K) molten nuclear fuel (UO2) and water (with a large variation in absorption coefficient from the visible to the infrared) in a highly three-dimensional and inhomogeneous environment simulating the premixing phase of a steam explosion.