Indian Journal of Cryogenics

Generally, the pressure inside the propellant tank has to be maintained within the acceptable limits to avoid cavitation at the pump inlet. Heat and mass transfer processes occurring inside the tank has a considerable effect on the amount of pressurant gas entering to pressurize the tank. Ullage collapse leads to an increase in mass and mass flow rate of pressurant. Experimental data on tank pressurization is limited because of the enormous costs of performing large scale tank experiments using cryogenic fluids under controlled conditions. In this paper, collapse factor or pressurant gas mass has been investigated for certain combinations using Epstein and Anderson’s correlation and dimensional analysis and compared with the available experimental data. In some cases, operating pressure is kept constant while, in other cases, inlet gas temperature is kept constant. Combinations of pressurant and propellant like GH2- LH2, GN2-LOX, GHe -LOX are taken into account.