Numerical study on leakage, diffusion and accident consequences of liquid hydrogen jet and analysis of influencing factors

Abstract

Key equipment in liquid hydrogen refueling stations (LHRS), such as liquid hydrogen (LH2) storage tanks or cryogenic pumps, are usually equipped with multiple protective measures. The likelihood of a catastrophic explosion is minimal. More commonly, valve or pipeline failures occur, leading to LH2 jet release. This study utilizes three-dimensional computational fluid dynamics (CFD) software FLACS to develop a numerical simulation method for LH2 jet release. A simple open environment scenario was created, and experimental data were used to verify the feasibility of the numerical simulation principles. The study analyzed the effects of parameters such as wind speed and direction, presence of barrier walls, and the height and distance of these walls on the consequences of LH2 jet release incidents. Results indicate that for LH2 impingement jet, the longitudinal dispersion distance is greatest under downwind conditions. Under crosswind conditions, the horizontal dispersion distance, flammable volume, and flammable mass are highest. Under upwind conditions, the equivalent stoichiometric cloud volume, explosion overpressure, and damage area are the largest, resulting in the most severe consequences. As wind speed increases, the explosion overpressure and damage area under upwind conditions initially increase and then decrease, with the most dangerous wind speed being 5m/s. Walls can effectively reduce the hazard range of explosions and fires following liquid hydrogen leakage from small holes. The optimal wall height is between 3m and 4m, and the optimal distance from the leakage point is around 9m. These findings provide crucial engineering guidelines for optimizing barrier wall design and wind mitigation strategies in LHRS. Furthermore, by improving safety standards and reducing the risks of explosions, this research plays a pivotal role in fostering public trust and promoting the broader use of LH2 as a clean energy source.