CFD MODELLING OF CHUGGING CONDENSATION REGIME OF BWR SUPPRESSION POOL EXPERIMENTS

摘要

In this work, the chugging direct contact condensation (DCC) mode of BWR suppression pool operation is simulated by using Eulerian-Eulerian two-fluid approach of the compressible flow NEPTUNE_CFD software and the OpenFOAM CFD code. The interfacial heat transfer between steam and water is modeled by using condensation models based on the surface renewal theory. Flow turbulence is solved by employing the standard k-e turbulence model. As the condensation rate could not be measured experimentally, a pattern recognition algorithm was used to extract information about the bubble size and the chugging frequency during the steam discharges. The experimental references for the analysis and simulations have been obtained from the suppression pool test facility experiments of the Lappeenranta University of Technology. The reference cases contain steam discharges within the open pool test facility POOLEX and within the pressurizing drywell-wetwell test facility PPOOLEX. The simulation results indicate that the qualitative nature of chugging can be captured well with the computational fluid dynamics (CFD) modelling and better quantitative results can be reached by DCC model development.