Shape diagram determination of a multiphase system in stratified configuration by CFD

Dynamics of a multiphase flow phenomenon involving water (at top), molten metal (at bottom), and vapor (between them), was numerically studied using volume of fluid method. Multiphase flow systems like this are present in a wide range of industrial applications and natural phenomena and are extensively investigated because of their potential to produce energy. This work pays special attention to the interface shape because of its influence on heat transfer rate. An approach, new for systems larger than drop scale, which consists in the construction of an interface shape diagram based on Reynolds (Re) and Bond (Bo) dimensionless numbers is proposed. The presented model demonstrated good capability to discern the governing forces such as viscous, inertial, and surface tension. The most favorable interface shapes for efficient premixing of phases involved were identified. The premixing significance lies in its determining role in steam explosion generation. Moreover, the effect of density ratio and triggering pressure is examined. In addition, Kelvin–Helmholtz and Rayleigh–Taylor fragmentation mechanisms were observed, and their preponderance was analyzed. The results obtained were validated with previous experimental data available in the literature finding good agreement. This proposal aims to provide useful information to enhance our understanding of this phenomenon from a fundamental perspective, applicable to further numerical and experimental studies in different research areas.