Abstract:

 In order to find the most economical liquid level of the hydrogen tank during a launch vehicle’s long-term parking, then to formulate a reasonable launch process and emergency disposal method, the computational fluid dynamics (CFD) technology is used to simulate and analyze the thermodynamics in the hydrogen tank of the launch vehicle while parking. The Volume-of-fluid (VOF) two-phase flow model and Lee phase transfer model are selected. In order to improve the Lee model’s simulation accuracy under different pressure conditions, the Antoine equation is employed to modify it. The modified model is firstly validated by the test data, and the subsequent simulation of the liquid hydrogen tank parking indicates that there is the temperature stratification phenomenon in both the vertical and radial directions in the tank, a large vortex is formed in the liquid phase, and it will cause the continuous thermal change between the cold fluid and hot fluid and lead to the liquid hydrogen’s evaporation in the inner part of the tank. The maximum evaporation rate exceeds 2 m 3/h and occurs at about 4 h after parking, the evaporation rate is relatively low when the tank is filled to more than 37 m 3 or less than 17 m 3, and the minimum value is close to 1 m 3/h.

Key words: Tank, Lee model, Antoine equation, VOF model, Evaporation