Modeling of cryogenic hydrogen releases

Abstract

Hydrogen is likely to be stored and transported as a liquid with high densities to have sufficient hydrogen on-site and for efficient distribution. Thus, cryogenic hydrogen jets and dispersion characteristics need to be studied to quantify the risks of accidental releases. The present study modeled cryogenic hydrogen jets with stagnation temperatures around 50 K released from round nozzles at stagnation pressures of 2–10 bar. The instantaneous flow fields were modeled using the Large Eddy Simulation (LES) turbulence model to accurately and efficiently capture the flow characteristics. The numerical models were validated with experimental data. The concentration and velocity distributions show that the centerline mass fraction and velocity decay at similar rates to the decays for room temperature jets. The radial distributions of the mass fraction, temperature and velocity are Gaussian and self-similar. Additionally, the numerical model can reproduce the shock structures near the nozzle for these underexpanded cryogenic hydrogen jets. The location of the first normal shock was predicted to be closer to the nozzle than for room temperature jets. The present work can be used to develop and revise safety codes and standards for liquid hydrogen facilities.