Numerical simulation of three-phase flows with rich solid particles by coupling multi-fluid model with discrete element method

Guo, L.*; Morita, Koji*; Tobita, Yoshiharu

In core disruptive accidents (CDAs), the motions and interactions of solid particles, such as refrozen fuels, disrupted pellets, etc., not only dominate fundamental behaviors of multiphase flows, but also drastically influence the process of CDAs. In the fast reactor safety analysis code, SIMMER-III, strong ineractions among solid particles in multiphase flows with rich solid particles were not taken into consideration for fluid-dynamics models of SIMMER-III. In this article, a hybrid method for multiphase flows analysis is developed by coupling the discrete element method (DEM) with the multi-fluid model of SIMMER-III. In the coupling algorithm, motions of liquid and gas phases are solved by a time-factorrization (time-splitting) method. For the solid phases, contacts among particles and interactions with fluid phases are considered through DEM. Numerical simulations of dam-break behavior with rich solid particles show reasonable agreements with corresponding experimental results. It is expected that SIMMER-III coupled with DEM could provide a promising and useful computational tool for complicated multiphase-flow phenomena with high concentration of solid particles in CDAs.