NCCR - Aramid Sandwich Insulator for Cryogenic Applications

Abstract

Structural integrity of cryogenic propulsion system in which fuel and oxidizer tanks are connected using truss tubes was well established. The critical issue in the design is the temperature constraint so that temperature is limited to within K for LH2 tank as against K for the LOX. In the present work, based on transient heat transfer analysis for 600s, polyimide foam filled aramid honeycomb core sandwich insulator is designed for common bulkhead instead of truss tubes each for cryogenic and semi cryogenic systems. Non conducting cryo compatible resin (NCCR) is used to bond the skin and core. Comparison of the back wall temperature for different heat flux and different thermal specifications obtained from test and prediction shows a good agreement. The study shows that a small increase in core height of foam filled sandwich insulator considerably controls the temperature increase of LH2. Test data on flat - wise tensile strength at 77K of NCCR resin used in the honeycomb sandwich insulator shows the values in the acceptable range.