A boiloff calorimetry test configuration for the characterization of thermal insulation systems in flammable background gasses

Abstract

In support of efforts related to the design of future mega-scale liquid hydrogen storage tanks required to facilitate the global hydrogen economy, the Cryogenics Test Laboratory at NASA Kennedy Space Center has recently begun thermal performance characterization of various insulation systems in a gaseous hydrogen background using the Cryostat-100 (CS-100) liquid nitrogen boiloff calorimeter. The CS-100 is a vertical-cylindrical geometry, capable of measuring heat load and vacuum pressure ranges from 100 mW to 100 W, and 10^-8 torr to ambient pressure respectively, via the ASTM C1774, Annex A.1 standard methodology. Flammable gas testing required numerous augmentations to the standard CS-100 hardware configuration and controls software, and modifications to the Lab facility to ensure a safe test campaign. These included double-containment of the CS-100 vacuum chamber and most supporting hardware, with continuous inert gas purging using nitrogen; remote control of valves and vacuum pumps; and hydrogen and oxygen detection systems. The careful design and implementation of these unique modifications led to safe and successful CS-100 hydrogen testing, and will be presented and discussed in-detail.