Investigation of Tank Pressurization and Pressure Control—Part I: Experimental Study

Abstract

Self-pressurization and pressure control of cryogenic storage tanks have important design consequences for propellant and life support systems currently being planned for long duration space missions. During self-pressurization, the tank's liquid fill level and the heat load from the surroundings can have significant effects on the tank's thermal stratification and pressurization rate. When controlling pressure with a mixing jet, the velocity and temperature of the jet are important design parameters affecting the thermal destratification and pressure reduction time constants. In this work, a small-scale ground-based experiment was performed, as a precursor to a microgravity experiment, to investigate the effects of these variables on the pressurization and pressure control time constants in the tank and to assess the feasibility of using a forced jet mixer for reduced boil-off pressure control. Local pointwise temperature and pressure measurements, together with qualitative contours of the thermal field in the liquid, vapor, and wall region, were made to identify and characterize important self-pressurization and pressure control trends in 1 g.