Numerical simulation on pressure evolution process of liquid hydrogen storage tank with active cryogenic cooling

Inevitable evaporation process occurring in liquid hydrogen storage may bring about safety risks associated with over-pressure and hydrogen discharge. Using a cryogenic refrigerator to compensate for the heat leakage is expected to eliminate the risk of hydrogen vent, realizing long-term lossless storage. Presently, active lossless storage technology applied on civil fields has rarely been studied. This paper presents a numerical study on the dynamic evolution process within an active cooling system of a liquid hydrogen tank. The accuracy of the model is validated with an average deviation of 0.47%. During the self-pressurized process, the maximum temperature difference is more than 26 K in the ullage zone. After cooling capacity being introduced, a three-stage depres-surization process appears. Minor cooling capacity that is less than heat leakage can still realize pressure management. Further analyses show two operating modes similar to gravity heat pipes and thermal redis-tributors occurring in the ullage and the liquid zone, respectively. This work suggests the effectiveness of active cooling on controlling the ullage pressure, which may be applicable to future hydrogen refueling stations and intercity hydrogen transportation.