超大功率霍尔推力器放电参数影响仿真及试验

Simulation and Experiment on Effects of Discharge Parameters on Performance of Super Power Hall Thruster

关键词:  深空探测  大功率电推进  霍尔推力器  性能评估  放电特性

Key words:  Deep space exploration  High power electric propulsion  Hall thruster  Performance evaluation  Discharge characteristics

摘要:

针对超大功率霍尔推力器放电参数特性评估，开展放电电压和流量等参数变化对性能影响的仿真及试验研究，以确定推力器设计最优匹配的放电电压及放电电流工况。建立了Particle-in-Cell （PIC）数值仿真模型，并搭建了HET-450大功率霍尔推力器试验平台；针对变放电电压、变流量下推力器放电特性，仿真计算给出了放电通道内原子密度、电势以及电子温度等分布，探究了推力器电离和加速运行机理，进一步，结合试验，开展了放电电流、推力等比对分析。结果表明：放电电压从300V增加至500V过程中，电离效率逐渐提升，因而放电电流、推力以及阳极效率均递增，而继续增加放电电压则会导致过热场的产生，离子与壁面作用增强导致电离出的离子再次复合，工质利用率下降的同时壁面损失增加，宏观表现为阳极效率的下降。此外，仿真与试验所获得放电电流、推力等结果符合良好，说明建模合适；在500V，80mg/s条件下，推力达2.1N、阳极效率60%，达到设计要求，表明设计合理有效。

Abstract:

Aiming at evaluating the discharge parameter characteristics of super power Hall thruster， the simulation and experimental study of the effects of discharge voltage and flow rate on the performance were carried out to determine the discharge voltage and current condition matched best in the progress of thruster design. The PIC numerical simulation model was established and the HET-450 high power Hall thruster test platform was built. In view of the thruster discharge characteristics under variable voltage and flow rate， the distribution of atomic density， electric potential， electronic temperature and the ionization and acceleration mechanism of thruster are explored. Further， the discharge current and thrust are compared and analyzed in combination with the test. The results show that： with the discharge voltage increasing from 300V to 500V， the ionization efficiency increased gradually， so the discharge current， thrust and anode efficiency are increasing， while continuing to increase the discharge voltage will lead to the generation of overheating field， the enhancement of the interaction between ions and wall surface will lead to the recombination of ionized ions， the decrease of working medium utilization and increase of wall loss， which is macroscopically manifested as the decline of anode efficiency. In addition， the simulated thrust and discharge current are in good agreement with the measured ones at the same working condition， indicating that the simulation model is suitable. At the discharge voltage of 500V and the anode mass flow rate of 80mg/s， the thrust reaches 2.1N and the anode efficiency 60%， which meet the design requirements， indicating that the design is reasonable and effective.