Simulation of self-pressurization in cryogenic propellant tank

Abstract

In order to predict the pressure and investigate the interrelation among the physical processes in cryogenic propellant tanks, a 2D axial symmetry Volume-of-Fluid (VOF) computational fluid dynamic (CFD) model including a liquid propellant phase and a mixture real gas phase is established. The propellant phase change model is based on the assumption of thermodynamic equilibrium. Two comparisons between the simulation results and the self-pressurization tests of two different liquid hydrogen tanks are made to validate the model. And the deviations of pressure in the tanks are 2.7%~6.1%. The results indicate that the evaporation induced by the initial overheat is the key factor of the pressure rising in the liquid hydrogen tank at the beginning of self-pressurization, but has less influence when the tank becomes saturated.