| 研究実績の概要 |
The sensitivity analysis of initial temperature, coolant/melt viscosity, and crust fracture was performed to investigate their influence on melt fragmentation. The simulation results demonstrated that (a) melt fragmentation became more violent with the increase of melt initial temperature, (b) the melt/coolant viscosity did not significantly affect melt fragmentation, and (c) melt fragmentation did not vary essentially no matter the crust fracture model was enabled or not. The reason for the third point was that the employed resolution was not fine enough to capture the multi-scale fragmentation phenomena. Efficient parallelization for large-scale simulations is expected in future.
Besides, novel free-surface detection conditions and a new high-order free-surface-tension model were proposed. They will significantly enhance the stability and accuracy of the developed particle method.
Overall, the proposed techniques provide a novel direct numerical method to simulate the complicated gas-liquid-solid multiphase flows with solidification, melting, and vaporization phase changes in severe accident analysis. They can greatly extend the application range of numerical methods.
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