Study on the Self-Pressurization Laws of Cryogenic Liquid Krypton Tank for the Electric Propulsion System

Abstract

To meet the application requirements of zero boil-off storage of cryogenic liquid krypton propellant in the process of completing deep space exploration missions by electric propulsion system, it is important to study the thermodynamic changes in cryogenic liquid krypton tanks under different environments. The gas phase and liquid phase material model of krypton working fluid, the gas-liquid phase change model at the interface layers, and the heat transfer process between the wall and the internal fluid are established by ANSYS-Fluent. The energy source term, gas phase, liquid phase mass source term, and phase change saturation temperature in the liquid krypton cryogenic tank are defined. This paper’s three influencing factors of gravity, initial liquid filling rate, and wall heat leakage are simulated and analysed. The results show that: (1) The self-pressurization rate significantly rises as the wall heat flux rises, and the gas-liquid interface drops less quickly. The pressure and temperature in the tank are also increasing at the same liquid level. (2) In the normal gravity environment, the bigger the filling rate, the lower the corresponding self-pressurization rate. (3) In the process of variable gravity, the gas pressurization rate in the cryogenic liquid krypton tank falls with the decrease of gravity.