Modeling of Hydrogen Dispersion, Jet Fires and Explosions Caused by Hydrogen Pipeline Leakage

Abstract

Accidental hydrogen releases from pipelines pose significant risks, particularly with the expanding deployment of hydrogen infrastructure. Despite this, there has been a lack of thorough investigation into hydrogen leakage from pipelines, especially under complex real-world conditions. This study addresses this gap by modeling hydrogen gas dispersion, jet fires, and explosions based on practical scenarios. Various factors influencing accident consequences, such as leak hole size, wind speed, wind direction, and trench presence, were systematically examined. The findings reveal that both hydrogen dispersion distance and jet flame thermal radiation distance increase with leak hole size and wind speed. Specifically, the longest dispersion and radiation distances occur when the wind direction aligns with the trench, which is 110 m where the hydrogen concentration is 4% and 76 m where the radiation is 15.8 kW/m2 in the case of a 325 mm leak hole and wind under 10 m/s. Meanwhile, pipelines lacking trenching exhibit the shortest distances, 0.17 m and 0.98 m, at a hydrogen concentration of 4% and 15.8 kW/m2 radiation with a leak hole size of 3.25 mm and no wind. Moreover, under relatively higher wind speeds, hydrogen concentration stratification occurs. Notably, the low congestion surrounding the pipeline results in an explosion overpressure too low to cause damage; namely, the highest overpressure is 8 kPa but this lasts less than 0.2 s. This comprehensive numerical study of hydrogen pipeline leakage offers valuable quantitative insights, serving as a vital reference for facility siting and design considerations to eliminate the risk of fire incidents.