Abstract
Liquid hydrogen (LH2) storage tanks are equipped with pressure relief devices (PRD) to vent hydrogen and avoid the pressure build-up in a tank due to heat transfer from the ambient, including in case of fire. In the event of a PRD failure, the tank structural integrity may be compromised leading to catastrophic rupture of the storage tank releasing the stored energy and producing destructive blast wave, fireball and projectiles. The present paper presents a CFD model to investigate the underlying physical processes of what is called “BLEVE” and assess the blast wave generated by an LH2 storage tank rupture in a fire. The proposed CFD approach advances the previous model (Cirrone et al., 2023) to include the effect of flash evaporation of LH2 during pressure drop after tank rupture and reproduce the multi-peak overpressure structure observed in experiments performed by BMW. Simulation results show that the observed maximum pressure peak is associated with the gaseous phase “explosion”, whereas the series of secondary pressure peaks, smaller in amplitude and of longer duration, are associated with the flash evaporation of the LH2 fraction stored in the tank. Simulations can reproduce the minimum and maximum overpressures measured at 3 m from the storage tank in BMW experiments. The simulated maximum blast wave pressure is seen to increase with the storage pressure and volumetric fraction of the gaseous hydrogen phase in the tank prior to rupture.
