Numerical simulation study on liquid hydrogen leakage diffusion behavior and solid-air deposition formation.

Liquid hydrogen leaks can lead to the formation of solid-air deposition near the leakage source, and oxygen enrichment may exacerbate the risk of ignition of liquid hydrogen and combustible clouds. This study, based on NASA's large-scale liquid hydrogen leakage experiments, constructed a three-dimensional model to dissect the evaporation/condensation and melting/solidification processes of air components (water, oxygen, and nitrogen), aiming to analyze the phase transitions of each air component and study the concentration and extent changes of condensed air components and solid-air deposition over time. The findings indicated that after the leakage stopped, the concentrations of liquid nitrogen and oxygen initially increased and then decreased below the leakage source, related to the heat absorption from liquid hydrogen evaporation and ground heat exchange, while the range of solid-air deposition gradually diminished. This model provides a reliable prediction of solid-air deposition formation, offering a reference for further research. [Display omitted] • Condensation and solidification processes of nitrogen and oxygen are considered separately. • The concentration and range of liquid nitrogen and liquid oxygen continue to increase after the leakage is stopped. • The solidification range of nitrogen and oxygen decreases after the liquid hydrogen evaporates completely. • Thermal conductivity of ground conditions affects the duration of solid-air deposition. [ABSTRACT FROM AUTHOR]