Molten metal and water direct contact interaction research – II. Numerical analysis

• A two-dimension multi-phase thermal hydraulic code with VOF is developed.
• Two typical experiment phenomena are simulated by using the developed code.
• Comparing with experimental data, the deformation process has some agreement.
• Droplet fragmentation process triggered by external pressure pulse is simulated.

In the fuel–coolant interaction (FCI), thermal fragmentation of molten metal droplets could result in the propagation of pressure waves and subsequent fragmentation of other droplets and lead to steam explosion at last. It is recognized that the direct contact heat transfer and interface behavior are very important in the thermal fragmentation process. Two typical experimental phenomena are observed and introduced in the part I of the paper, named no interaction mode and explosive interaction mode. In this paper, a two-dimensional multi-phase thermal hydraulic code with the Volume of Fluid Method (VOF) is developed to investigate the direct liquid–liquid contact interaction behavior with large temperature difference. Two typical experiment phenomena are simulated by using the developed code, which are observed in the experiment and introduced in part I of this paper. Comparing with the experimental visual data, the simulation results are in a good agreement. At last, the thermal fragmentation process of melt drop triggered by external pressure pulse during FCI is simulated by using the developed code. The calculation results suggest that the growth and breaking up of filaments are the essential mechanism of molten metal droplet fragmentation.