Study on thermal analysis simulation and test of propellant refueling process for optical module

Abstract

Propellant refueling is important for long-term operation of the optical module in orbit. However, its thermal environment is harsher than on previous missions. Therefore, thermal control of the entire process is required. In order to solve the complex heat transfer of propellant refueling process, an integrated thermal model is established, which includes all the equipment such as the compressor, liquid cooler and loop heat pipe. The thermal analysis simulation and system-level thermal tests is presented. Firstly, the heat transfer relationship and temperature variation are analyzed by comparing the results of transient thermal analysis and thermal test in high and low temperature conditions. Then, a variable thermal conductivity simulation method is studied for the transient process from inoperative to operative of the vertical heat pipe due to gravitational factors in the thermal test. Finally, an optimized design scheme for high temperature refueling is proposed and pre-demonstrated in orbit. The results indicate that the transient simulation results are in a good agreement with the test results under the high and low temperatures, which verifies the accuracy and validity of the analysis method and simulation model. When preheating the compressor and starting two sets of loop heat pipes during on-orbit refueling, the maximum temperature of compressor is below 34.1°C, and the total power consumption of preheating is 50 Wh, which meet the design requirement. The investigation provides an important reference for designing the propellant refueling process in the docking of the optical module to the China Space Station (CSS).