Application of Computational Fluid Dynamics in Simulating Film Boiling of Cryogens

This paper presents a computational fluid dynamic (CFD) model, simulating film boiling based on Rayleigh-Taylor (R-T) instability, using the volume of fluid (VOF) method to track the liquid/vapor interface. Film boiling of cryogenic liquids (e.g., LNG and liquid nitrogen) is simulated to estimate the vapor generation rate during an accidental spill. The simulated heat fluxes were compared with heat fluxes obtained from Berenson and Klimenko correlations. The effects of wall superheats on the bubble generation frequency were studied. This study helps researchers to understand the physics of film boiling that are useful during the risk assessment of a cryogenic spill scenario. For example, it was found that the bubble released from the node and the antinode points between the consecutive bubble generations cycles do not follow the alternating nature under the realistic film boiling conditions. Therefore, empirical expressions assuming alternating bubble generation might be unsuitable for cryogenic vaporization source term estimation.