Numerical study of thermal hydraulics behavior on the integral test facility for passive containment cooling system using GASFLOW-MPI

Abstract

A dynamic film model is developed in GASFLOW-MPI to study the thermal-hydraulic behaviour of the containment with external film cooling, i.e. the passive containment cooling system (PCCS). Former researches on PCCS are mainly conducted with lumped parameter computer codes, hence the CFD study coupling both sides of the containment is necessary. In this study,the dynamic film model of GASFLOW-MPI is validated with both a separate effect test EFFE (Experiments on Falling Film Evaporation) facility and an integral test facility. Firstly, the 2D model of the EFFE facility is built and analyzed in both dry cases and wet cases. The results agree well with the experimental data indicating that the dynamic film model of GASFLOW-MPI can provide reasonable predictions for both heat and mass transfer between the film and gas. Then the 3D model of the scaled down containment test facility is built with the cylindrical coordinate, and a mesh sensitivity analysis is conducted with one section of the 3D model. The 3D model results show that the steady state analysis of GASFLOW-MPI has good agreement with experimental data. Furthermore, GASFLOW-MPI manages to capture the thermal stratification in the containment which is underestimated in former research. The heat transfer analysis on both sides of the containment shell shows that the steam condensation in the dome contributes almost 50% to the total steam condensation, while the film evaporation in the cylinder part contributes about 90% for the heat removal of PCCS. This is the result of heat and mass transfer on both sides of the containment shell coupling with each other. The validation of these two cases indicates that the GASFLOW-MPI can provide reasonable predictions for the thermal hydraulics behavior on both sides of the containment when implementing PCCS. Further research will focus on transient analysis and the model for film coverage.