Test study of the operating performance of a mechanically pumped two-phase loop for a space remote sensor

To increase the imaging indexes of space remote sensors, temperature stability is required for the core optical detector assembly in the working stage. However, with traditional products, it is difficult to meet the requirements of precise temperature control for a high-power module. A mechanically pumped two-phase loop (MPTL) is highly advantageous as an essential thermal control product in space cameras. In this study, one MPTL setup was constructed to investigate the operating behaviors caused by the heat source of the core detector assembly for the load-on and load-off status. One two-phase thermal-controlled accumulator integrated with passive cooling was first employed as the temperature control component of the system, and the shield centrifugal pump was selected to be the driving force. The obtained test data, which included the temperature, pressure, and mass flow-rate, were used to analyze the thermodynamic behaviors in the accumulator. In addition, the heat and mass transfer processes between the main loop and the accumulator and the operating characteristic of the main loop were investigated. This research focuses on the instability phenomena that occur during the phase transition of the system and during the heat source load-on and load-off status; a method to decrease the system instability has been proposed. In addition, the operating behaviors of the main loop and the accumulator during the power change of the heat source have also been investigated. The results show that there was a temperature difference between the gas and liquid phases in the accumulator, and the cooling capacity of the accumulator was obtained as the temperature difference. The temperatures of the multi-evaporators showed excellent performance in the area of stability and uniformity, which provided good boundary conditions for the stabilization imaging of the space camera. The temperatures and pressure in the accumulator and the flow-rate and flow resistance of system will be affected by the starting up and powering off of the heat sources. The system stability during the process of phase change was influenced by the loading power on the pre-heater. The variations in the heating load affect the operating state of the accumulator and main loop. The results obtained from this study can be used to guide the design and application of the MPTL system for space remote sensors.