Solubility of Pressurant Gases in Liquid Hydrazine at Elevated

Abstract

Many propellant delivery systems use helium gas for storage, pumping, and pressurizing liquid propellants for in-space applications. To properly understand propellant tank functionality, reliable data on the solubilities of pressurant gases in these propellants are needed. Thus, the solubility of helium in liquid hydrazine has been measured as a function of pressure and temperature. The current measurements were conducted at pressures relevant to in-space applications of 0 to 1000 psia for the first time. The temperature dependence was studied in the relevant temperature range of 278 to 308 K. The current results do not agree with the only previous measurement of helium solubility in hydrazine. These previous measurements were conducted in a much lower-pressure regime. The cause of the discrepancies between the current measurements and the previous measurements is unclear. The solubilities of nitrogen and argon at 293.15 K were also measured to better understand the discrepancies between current and previous experiments.