Investigation of an RLV Cryogenic Tank Insulation Including a Purge Gap System

Abstract

An interface design between structure, cryogenic insulation and thermal protection system (TPS) is developed for a reusable cryogenic propellant tank as part of the DLR research project AKIRA. As reference vehicle the booster of the conceptional reusable launch vehicle SpaceLiner7 is chosen. The design comprises a purge gap between cryogenic insulation and TPS and a fixation element to attach the TPS and the purge system to the tank structure. An integrated test object (ITO) is developed to investigate the efficiency of the purge gap within the compound of tank structure, insulation system and fixing elements. An experimental setup is presented which shall prove both functionality and reusability of the design, represented by the ITO, with respect to the thermal boundary conditions of fuelling phase and re-entry of the reference vehicle. Additionally, fluid simulations were carried out to assess the flow variables with which the purge gap shall be operated during the experiments to meet the requirements.