Test Data Analysis of the Vented Chill, No-Vent Fill Liquid Nitrogen CRYOTE-2 Experiments

Abstract

NASA is interested in developing efficient methods with which to transfer cryogenic propellants to enable future in-space cryogenic propellant vehicles, particularly the cryogenic fuel depot. The process of transferring cryogenic propellants between two vessels in a reduced gravity environment is complicated by the low normal boiling point of cryogens, high propensity for boiling during tank chilldown, and the fact that liquid cannot be transferred with the receiver tank vent valve open to space. This paper presents test data analysis of the liquid nitrogen vented chill, no-vent fill (NVF) experiments on the CRYOTE-2 tank. 53 tests were conducted, and while not originally intended, were performed in a somewhat parametric fashion. Performance between three different injectors are compared, as well as the effect of initial receiver tank wall temperature, receiver tank fluid initial condition, supply pressure, mass flow rate, and trigger point on the NVF process. From in-depth test data analysis, the highest performing injector based on maximizing evaporation heat and mass transfer between droplets and ullage as well as condensation heat transfer at the liquid/vapor interface, was the 3-spray injector.