Plume dispersion behaviour and hazard identification for large quantities of liquid hydrogen leakage

Hydrogen is a promising energy carrier. The primary issue of hydrogen utilisation is safety in various scenarios for the coming hydrogen economy. This study focuses on liquid hydrogen leakage, which is typically induced by structural failure in refuelling stations and transit vehicles. In the present study, the authors reveal the plume dispersion behaviour and the underlying mechanism from a macro perspective and identify the associated hazards in the whole dispersion history. These problems have drawn little attention in previous studies. A numerical investigation was conducted, and the flow-field data were deeply investigated, which were insufficient in the previous experiment. The local turbulence and mixing induced by the temperature difference was revealed to be the major cause of hydrogen dispersion. The lift force induced by the density difference enhanced the dispersion. The dispersion behaviour was classified into three phases: the dense-gas phase, rise phase, and passive phase. The rise phase is the major one for cryogenic hydrogen dispersion. The frostbite hazard can be ignored, owing to insufficient exposure duration. For wind velocities of 2.2, 5.0, and 10.0 m/s, the durations of the hazardous cloud are 56, 51, and 47 s, respectively. The maximum heights of the hazardous cloud are 23.6, 12.1, and 6.2 m, respectively. There is a high fire/explosion probability in the dense-gas phase and a low probability in the latter two phases.