CFD simulation of spray cooling in the model containment THAI

CFD (Computational Fluid Dynamics) simulation of spray is a challenging task in the field of nuclear reactor safety. In the current publication a CFD model for spray cooling is presented, which is able to predict heat and mass transfer between cold droplets and a hot humid air gas atmosphere. The model, which is implemented via user defined functions in the commercial CFD code ANSYS CFX 16.1, enables the simulation of spray cooling physics with an Euler-Euler two-fluid approach. A comparison of simulations with mono-and polydisperse spray configurations shows the relevance to consider droplet size distributions within spray. For validation, the pressure and temperature transients of the experiment THAI HD-31-SE (Thermal-hydraulics, Hydrogen, Aerosols and Iodine) are used. During the experiment, a cold spray is injected into a hot humid air gas atmosphere, which leads to a cooling effect inside of the model containment. A full three dimensional geometrical mesh of THAI is used for all simulations. Simulation results indicate a good agreement with experimental data for the polydisperse spray configuration.