Design and Analysis of a Vapor Cooled Shield of Cryogenic Propellants Storage System

Vapor-cooled shield(VCS)has been considered as an effective technology to intercept heat leakage from the environment into the cryogenic tanks. This paper shows a 3 D model to investigate the temperature distribution on VCS with H2,and also conforms to the fact of temperature uniformity assumption in literature. The shield wall thickness is analyzed for series-type VCS and parallel-type VCS to clarify the existing temperature gradient on VCS and the way it influences the insulation performance of multilayer insulation(MLI). Computational fluid dynamics(CFD) simulations are performed on different VCS types,and the simulation results showed that the temperature gradient between series-type VCS and parallel-type VCS is about 2 K with 2 mm thickness. Therefore,according to the VCS configuration design,there is no obvious influence of temperature distribution between both tseries-type VCS and parallel-type VCS. The effects of VCS position and warm boundary temperature(heat flux) on the thermal insulation performance were investigated for LH2 and LO2 tanks. The temperature profiles within the insulation material with or without VCS are compared. In addition,the contributions from the VCS to reduce the heat flux into the tank,especially to the LH2 tank,are evaluated. The simulation results indicate that the temperature gradient of VCS increases as the wall thickness decreases,the maximum temperature gradient is less than 1.5 K and can be regarded as the isothermal surface. Besides,the heat flux through MLI increases as the temperature gradient of VCS increases,but with a very small growth rate. Therefore,the influent of the VCS temperature gradient could be ignored on the adiabatic property of MLI.