Parahydrogen–Orthohydrogen Conversion on Catalyst-Loaded Scrim for Vapor-Cooled Shielding of Cryogenic Storage Vessels
Brandt P. Pedrow, Santhosh K. Muniyal Krishna, Elijah D. Shoemake, Jacob Leachman, Konstantin I. Matveev
Abstract
As long-distance human space travel becomes more realistic, the need for long-term storage of cryogenic propellants becomes a forefront issue. Effective cryo-fluid system management becomes a necessity to solve this issue. The fuel–oxidizer combination of choice for NASA’s Space Launch System is liquid hydrogen and liquid oxygen (LOX). The current strategy used on many upper stage vehicles, including United Launch Alliance’s Advanced Cryogenic Evolved Stage, is to use the boil-off gases of the colder cryogen to help insulate the warmer cryogen (LOX) and reduce the static boil-off. In this work, experimental measurements are collected for a range of catalyst materials and weight loadings of and catalysts on Nomex scrim blankets. The blankets are configured in a nonisothermal catalytic reactor with a 23 K input temperature and heated to 90 K output temperature. Results of catalyzation of parahydrogen to orthohydrogen gas are presented as well as a catalyzation model to represent the measurements for future use. In addition, simplified computational fluid dynamics studies have been initiated to estimate the surface-based conversion rate constant by matching numerical results and experimental data.