An Extension of the Large-Cell Radiation Model for the Case of Semi-Transparent Nonisothermal Particles

The recently developed model for thermal radiation in multiphase flows typical of melt-coolant interactions is generalized to account for transient temperature profile in large semi-transparent particles of solidifying melt. A modification of the Large-Cell Radiation Model (LCRM) is based on approximate solution for coupled radiation and conduction in optically thick spherical particles of a refractive material. The simplicity of the suggested approximation enables one to implement the modified model in a multiphase CFD code. The LCRM extension makes possible the use of this approach not only for the core melt in nuclear fuel-coolant interactions (FCI’s) but also for other melt substances which are widely used in the laboratory experiments. The numerical data demonstrate an effect of absorption coefficient of the particle substance on the rate of particle cooling and solidification.