In-depth analysis of mixing characteristics of stratified gases during spray operation in the TOSQAN Test 113 using OpenFOAM

Abstract

During the severe accident of a nuclear power plant, the hydrogen is generated by the reactor core oxidation which may be stratified or distributed in the containment building. There are risks such as hydrogen explosion at a certain concentration of hydrogen, and therefore a detailed analysis is needed to assess the hydrogen risk. Meanwhile, the spray system operates as part of a severe accident strategy, and the dynamic effects of spray, in particular, are expected to have a significant impact on the gas entrainment and global mixing. Some parameters such as a buoyancy term in a turbulence model and particle diameter affecting the global behavior, have been reported in the previous researches. However, the detailed mechanisms of the dynamic aspect of spray were not described. Thus, the present study aims to perform an in-depth analysis of the effect of the buoyancy term in a turbulence model and the droplet size on the mixing characteristics (mixing tendency and mixing time) in TOSQAN 113 test.