Spread characteristics of hydrogen vapor cloud for liquid hydrogen spill under different source conditions

Abstract

During the storage and transportation processes of liquid hydrogen, the accidental spill could cause great damage. Mixture multiphase model and Realizable k-ε model are adopted to predict the spread of hydrogen cloud in liquid hydrogen spill. Effects of source parameters on spread characteristics of hydrogen cloud, including spill rate and liquid mass fraction, are analyzed. For the spill with various spill rates, the cases of fixed spill amount or spill time are considered in view of emergency response strategy to the spill source. The results show that the spreads of hydrogen vapor cloud in downwind and vertical directions can be both promoted by increasing the spill rate. When the total spill amount is fixed, the volume ratio of detonation cloud to flammable cloud at the spill termination instant increases firstly and then decreases with spill rate, due to the combined effects of near-source turbulence and mixing time with air. When the source is terminated after a fixed spill period, the detachment distances of flammable vapor cloud keep almost constant for the spill rates below 9.52 kg/s, while the cloud is more lifted if further increasing the spill rate, during which the role of the near-source turbulence overweighs that of the spill amount. The upward movement of flammable vapor cloud is promoted by increasing liquid mass fraction, with increased height and reduced detachment distance. The work provides a guidance to risk assessment and safe handling of liquid hydrogen.