Thermal Design of a Purged Cryogenic CFRP Tank and TPS Test Demonstrator for RLV

Abstract

In the TRANSIENT project of DLR, critical technologies for reusable launch vehicles are investigated. One of the critical aspects identified is the structural attachment of thermal protection system surface panels to the main vehicle structure if this is a cryogenic tank at the same time. In the preceding project AKIRA it was found that the inclusion of a purging system between the cryogenic insulation on the tank and the thermal protection system reduces the required wall thickness of the insulation system considerably in the case of certain requirements. In the TRANSIENT project thermal management aspects are investigated in the case of a cryogenic CFRP fluted core tank structure, this time including a purge system within the tank structure. The thermal protection system is based on the use of ceramic matrix composite surface panels. On the tank outside, an insulation system consisting of a layer of cryogenic insulation and high-temperature insulation is installed. The investigations were done employing numerical simulations to design the required wall thicknesses of the insulation layers, determine material choices for the thermal protection system attachments and find the required parameters for the purge gas flow with regard to gas temperature and mass flow.