Thermodynamic performance of pre-pressurization in a cryogenic tank

Abstract

To supply more actual initial physical field for launch of cryogenic propellant tank, it is necessary to investigate the thermodynamic performance of propellant tank before launch. As cryogenic propellant tank will experience the ground open parking and ground pre-pressurization phase, the present study is particularly to investigate the pressurization performance and temperature distribution in a cryogenic liquid oxygen (LOX) tank for the above parts. One CFD model is established with both the vapor-liquid interface phase change and external forced convection heat exchange considered. The results show that during the ground parking part, the intense nucleate boiling appears in cryogenic tank firstly, then the boiling intensity becomes weak, finally, it tends to be stable. With the high temperature gas oxygen (GOX) injecting into tank, tank pressure fluctuates among the setting pressure limits. The ullage is condensed during the whole pre-pressurization part. Influenced by heat transferring from the ullage and the external heat leakage, the thermal stratified layer becomes thick with time continuing. With the environmental temperature varying from 253.0K to 313.0K, its effect on tank pressure and liquid temperature distribution is not so obvious in this study. The unique large change is that the ullage center line temperature increases with the rise of environmental temperature, while the other parameters have slight changes.