离子推力器外壳非预期放电抑制实验研究

Experimental Study of Unexpected Breakdown Reduction of Ion Thruster Housings

关键词:  离子推力器  外壳  非预期放电  热设计  绝缘击穿

Key words:  Ion thruster  Housings  Unexpected breakdown  Thermal design  Insulation breakdown

摘要:

离子推力器非预期放电直接影响其在轨应用可靠性，为了降低推力器外壳与屏栅间的非预期放电频率且兼顾热设计提出3种优化方案，搭建了方案验证试验系统。研究结果表明：电荷在绝缘层积累是非预期放电的主要诱因，等离子体和气体泄漏是次要诱因，外壳非预期放电频率随功率增大呈上升趋势，0~3kW，放电频率从1.9次/h缓慢上升到3.3次/h，超过3kW，放电频率快速上升到6.9次/h。通过试验验证确定了最佳抑制方案，3kW工况下，该方案非预期放电频率从原方案的3.3次/h下降到0.05次/h，5kW工况下从6.9次/h下降到0.21次/h，且满足推力器热设计要求，240h性能测试中推力器关键性能参数偏差小于3%，推力器非预期放电得到有效抑制。

Abstract:

Unexpected breakdown of ion thruster affects its reliability in satellite orbit application. In order to reduce the frequency of unexpected breakdown between the thruster housings and the screen grid potential， while considering the thermal design of the thruster， three design options were proposed， the housing unexpected breakdown suppression scheme verification test system was built.The results of the study show that the accumulation of charge on the surface of the insulation is the main cause of unexpected breakdown， with plasma and gas leakage being secondary causes. The unexpected breakdown frequency of the housing increases with the increase of power， the breakdown frequency slowly rises from 1.9 times/h to 3.3 times/h under 3kW， over 3kW， the breakdown frequency quickly rises to 6.9 times/h. The best suppression scheme was determined through test verification， after optimization， the frequency of unexpected breakdown was reduced from the previous 3.3 times/h to 0.05 times/h at 3kW and from 6.9 times/h to 0.21 times/h at 5kW， and met the thermal design requirements of the thruster. The key performance parameter deviation of the thruster was less than 3% in 240h performance tests. Unexpected breakdown of ion thrusters was effectively reduced.