Pool spreading and vaporization of liquid hydrogen

An essential part of a safety analysis to evaluate the risks of a liquid hydrogen ( LH 2 ) containing system is the understanding of cryogenic pool spreading and its vaporization. It represents the initial step in an accident sequence with the inadvertent spillage of LH 2 , e.g., after failure of a transport container tank or the rupture of a pipeline. This stage of an accident scenario provides pertinent information as a source term for the subsequent analysis steps of atmospheric dispersion and, at presence of an ignition source, the combustion of the hydrogen–air vapor cloud. A computer model LAUV has been developed at the Research Center Juelich, which is able to simulate the spreading and vaporization of a cryogenic liquid under various conditions such as different grounds (solid, water). It is based on the so-called shallow-layer differential equations taking into account physical phenomena such as ice formation, if the cryogen is spilled on a water surface. The presentation will give a description of the computer model and its validation against existing experimental data. Furthermore calculational results will be analyzed describing the prediction and quantification of the consequences of an LH 2 spill for different cases. They also include the comparison of an LH 2 spillage versus the corresponding release of other cryogens such as liquid natural gas, liquid oxygen, and liquid nitrogen.