3D simulations of the hydrodynamic deformation of melt droplets in a water pool

Topic of present study emerges from the hypothetical nuclear severe accident in light water reactor (LWR) where molten fuel core may interact with a reactor pool causing steam explosion. Fundamental research is important to substantiate the knowledge of steam explosion energetics. In order to get the basic understanding of single droplet behavior during steam explosion phenomena, the present study is carried out to deal with hydrodynamic deformation of a droplet during preconditioning, the initial phase of fuel coolant interactions. The three-dimensional simulations are carried out with the help of volume of fluid (VOF) method using the CFD code ANSYS FLUENT. The deformation modes and deformation rate of a droplet initialized with different Weber numbers (We) are analyzed, followed by the separate-effect studies of droplet density and viscosity. As a next part, a droplet is exposed to high-intensity pressure pulses in order to study the deformation/breakup of the droplet at sudden accelerations. Finally, the deformation rates of the droplets starting solidification are analyzed, where the droplets are modeled with a modified surface tension.