Modeling and analysis of the flammable vapor cloud formed by liquid hydrogen spills

A three-dimensional CFD model for the flammable vapor cloud formed by liquid hydrogen spills was built and validated by the NASA experimental results, where a two-phase jet was released into a spill pond surrounded by a fence. Mixture multiphase model, combined with Realizable k-ε model and gas transport equation was adopted. The emphasis was focused on the evolution features of the flammable vapor cloud and the inner turbulent fluctuations in diffusion processes. In addition, the concentration and temperature relations for the flammable cloud were examined. The flammable vapor cloud is found to undergo three different evolution stages, namely the initial stage, the quasi-steady spread stage and the disappearance stage. The composition differences between the cloud and undisturbed air play a major role in vertical turbulent fluctuation, while the wind will dominate with the increment of height in streamwise direction.