Proceedings of the
35th European Safety and Reliability Conference (ESREL2025) and
the 33rd Society for Risk Analysis Europe Conference (SRA-E 2025)
15 – 19 June 2025, Stavanger, Norway
Modeling of Accidental Liquid Hydrogen Spills and Rainout
1Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology, Richard Birkelands vei 2B, 7034 Trondheim, Norway.
2Environmental Research Laboratory, National Centre for Scientific Research Demokritos (NCSRD), Aghia Paraskevi, Attikis, 15310 Athens, Greece.
ABSTRACT
Liquid hydrogen (LH2) is a clean energy carrier that is gaining traction for its versatility. Nevertheless, its use may lead to significant risks due to its low storage temperature, low boiling point, rapid vaporization, and high flammability. In the event of a loss of containment, if a portion of the LH2 does not fully vaporize and reaches the ground, the rainout phenomenon occurs. If the release is continuous, a pool of LH2 might be generated, raising the risk of delayed ignition, which may lead to large-scale fires or explosions. Thus, this study aims to understand the behavior of such cryogenic releases to mitigate potential risks. The simulations of LH2 releases involve the analysis of key factors such as the quality of the fluid, operating pressure of the tank, and jet velocity. This study adopts an integral model to predict the diameter of the LH2 droplets and their vaporization rate, the rainout, and the potential formation of an LH2 pool. The simulations help assess worst-case scenarios and determine the LH2 concentration profiles on the ground. The integral model allows for a preliminary evaluation of real-world release scenarios in hydrogen storage and transport.
Keywords: Hydrogen safety, Liquid hydrogen storage, Liquid hydrogen spillages, Rainout, Pool formation, Integral model.
