Numerical Simulation of Large Flow Liquid Discharge Process in Cryogenic Tank

Large cryogenic storage tanks are widely used in large-scale cryogenic liquid storage in aerospace, energy, chemical and other fields.It is very important for the safe operation of the system to ensure the stability of discharge and no entrain of gas in the process of large flow discharge of large cryogenic storage tank.The computational fluid dynamics(CFD) model of a 3 000 m³ liquid nitrogen storage tank and its drainage pipelines was established for the discharge of liquid at a high flow rate of 2 000 m³/h, and the gas-liquid interface, flow field, vortical field and pressure fluctuation of pipeline were analyzed.The influence factors of critical submergence level of cryogenic tank and the role of the anti-vortex plate in the liquid discharge process were further discussed.The results show that the critical submergence level is below 0.15 m in the large flow discharge process from stable state, and the liquid level remains stable without an obvious vortex.The initial liquid level of the cryogenic storage tank has little influence on the critical submergence level, while the anti-vortex plate hinders the fluid flow during the discharge process, which will lead to an increase in the critical submergence level.This study can provide guidance for stable operation of drainage system of large cryogenic storage tanks.