Towards safer hydrogen refuelling stations: insights from computational fluid dynamics on LH₂ leakage

Scaling hydrogen as a key clean energy carrier necessitates a comprehensive understanding of the safety aspects of hydrogen including liquid hydrogen (LH₂). Hence, this study presents a detailed computational fluid mechanics analysis to explore accidental LH₂ leakage and dispersion in a hydrogen refuelling station under varied conditions which is essential to prevent fire and explosion. The correlated impact of influential parameters including wind direction, wind velocity, leak direction, and leak rate were analysed. The study shows that hydrogen dispersion is significantly impacted by the combined effect of wind direction and surrounding structures. Additionally, the leak rate and leak direction have a significant effect on the development of the flammable cloud volume (FCV), which is critical for estimating the explosion hazards. Increasing wind velocity from 2 to 4 m/s at a constant leak rate of 0.06 kg/s results in an 82% reduction in FCV. The minimum FCV occurs when leak and wind directions oppose at 4 m/s. The most critical situation concerning FCV arises when the leak and wind directions are perpendicular, with a leak rate of 0.06 kg/s and a wind velocity of 2 m/s. These findings can aid in the development of optimised sensing and monitoring systems and operational strategies to reduce the risk of catastrophic fire and explosion consequences.