Thermal analysis of coupled vapor-cooling-shield insulation for liquid hydrogen-oxygen pair storage

Abstract

The long-term storage of liquid hydrogen (LH2)-liquid oxygen (LO2) pair with extremely low heat leakage is essential for future deep space exploration. Vapor-cooled shield (VCS) is considered an effective insulation structure that can significantly reduce the heat penetration into the LH2 tanks, however it is relatively ineffective for the LO2 tanks. Novel coupled VCS insulation schemes for LH2-LO2 bundled tanks were proposed to achieve optimal performance not only for the LH2 but also for the LO2 tanks. A thermodynamic model had been developed and validated by experiments. The optimal VCS location, the temperature profile within the insulation, the heat leakage reduction contributed by the VCS, and the thermal performance versus scheme structural mass had been parametrically investigated. A comparison indicated that the proposed single integrated shield configuration can reduce the heat flux of the LH2 and the LO2 tanks by 64.0% and 54.8%, respectively compared with the non-VCS structure. In addition, the results also confirmed that zero boil-off storage of LO2 can be achieved by only utilizing the exhausted hydrogen vapor, with no need for an extra cryocooler.