CFD STUDIES OF SUBCOOLING OF LIQUID CRYOGENIC PROPELLANTS BY HELIUM BUBBLING

Gaseous helium (He) bubbling through liquid cryogenic propellants stored in tanks is an effective method for subcooling of the propellants before rockets are launched. The present work focuses on numerical investigation of liquid oxygen subcooling by bubbling gaseous helium from a submerged orifice at the bottom of a liquid oxygen tank. Major focus has been given to computational fluid dynamics (CFD) simulations in ANSYS Fluent using multiphase modeling. The CFD model is demonstrated in detail and the results from the CFD model are clearly described. These results are compared against those obtained from a one-dimensional (1D) mathematical model based on finite heat transfer and instantaneous mass transfer. This 1D model is validated against experimental values. The presented results show that increasing the He injection flow rate increases the cooling rate. Additionally, increasing the He injection temperature decreases the cooling rate. It was also observed that increasing the ullage pressure suddenly causes an increase in temperature instead of a decrease. These variations of trends are found to match with those obtained in the validated 1D model against the experimental values.