Development of a numerical model to predict self-pressurization and thermal stratification in a cryogenic storage vessel

Thermal stratification in cryogenic storage containers and launch vehicle propellant tanks is an important design consideration because of its direct influence on tank pressure rise and turbo pump cavitation. The rate of self-pressurization in a liquid oxygen cryogenic container is predicted using a CFD model. The Lee phase change model is used to calculate evaporation and condensation, and the volume of fluid approach is utilised to forecast the movement of the liquid-vapor interface. The results were validated by experiments conducted at the cryogenic test facility, NITC. Analyses are carried out to determine the effect of tank radius on the evolution of stratification. The aspect ratio of the tank with radius R and the liquid filling height H is established. Three alternative aspect ratios are chosen to study the influence of tank radius. It is found that cryogenic tanks with smaller aspect ratio (H/R) require more time to fully stratify and have a lower self-pressurization rat