THERMAL-HYDRAULIC ANALYSIS OF A PASSIVE CONTAINMENT COOLING SYSTEM USING DYNAMIC LIQUID FILM MODEL IN CFD CODE GASFLOW-MPI

摘要

Falling water film modeling is crucial for the thermal hydraulic analysis of passive containment cooling system in advanced light water reactors. A dynamic liquid film model has been developed in the 3-D parallel CFD code GASFLOW-MPI to track the water film transport over the external surface of the steel containment. The gas phase, both inside and outside of the containment, the steel containment and the falling water film are coupled with each other through the essential source terms of inter-phase transport. The model has been verified by the Nusselt solution. Since very few useful experimental data can be found in the open literature, we compared the numerical results of GASFLOW-MPI and COMMIX code which is considered to be reliable because the code has been validated by the experimental data of the Westinghouse small/large scale integral test facilities. A passive containment cooling system has been simulated using the dynamic film model in GASFLOW-MPI. Good agreement was obtained when compared to the COMMIX results, regarding the water film thickness, velocity and temperature. The effect of mesh sensitivity on the heat and mass transfer needs further study. Further work is required concerning the heat transfer, evaporation and boiling at the interface of water film and gas mixtures in the annular space. Local film dry-out model will be implemented in the GASFLOW-MPI. In general, the calculation results using the dynamic film model positively demonstrated the capability of CFD code GASFLOW-MPI in simulation of passive containment cooling system.