基于加速栅溅射腐蚀失效的离子推力器寿命预测

Life prediction of ion thruster based on sputtering erosion failure of accelerator grid

离子推力器加速栅溅射腐蚀失效是制约离子推力器寿命的关键失效模式之一.针对离子推力器长寿命、多功率条件下运行的特点,基于坑和凹槽的溅射腐蚀数据,建立模型对其进行寿命预测.通过研究离子推力器加速栅中心凹槽腐蚀深度在不同功率段下随工作时间的变化规律发现:运行功率顺序对加速栅凹槽腐蚀率影响较小,进而采用累积损伤理论建立离子推力器多功率段下运行的寿命预测模型.最后,对美国的NASA's Evolutionary Xenon Thruster(NEXT)进行了寿命预测,预测结果寿命为46041h,与试验结果符合较好.

A crucial failure mode restricting the life of ion thruster lies in the sputtering erosion of accelerator grid. For the characteristics of long life and multi-power working, a corresponding model was used to predict the life of ion thruster based on the accelerator grid pit and groove erosion data. Firstly, by analyzing the change law between accelerator grid groove depth and operating time under various power segments, it was found that the operat-ing power sequence had little influence on the erosion rate of groove. And then the fatigue accumulation damage was introduced to establish the life prediction model for ion thruster operating under multi-power segments.At last, the life prediction model was used to predict the life of NASA＇s Evolutionary Xenon Thruster （NEXT）. The predicted result of 46 041 h coincides with the test well.