多模式离子推力器放电室和栅极设计及其性能实验研究

Design and performance test of discharge chamber and grid for multi-mode ion thrusters

针对小天体探测任务对离子推力器设计要求,完成总体方案设计,开展了四极环形磁钢会切场放电室和凸面三栅变孔径栅极设计,采用试验研究和理论分析的方法研究了放电室、栅极设计的合理性及匹配性,试验结果表明:多模式离子推力器实现了宽范围稳定放电和引出,在277—3120 W功率下,推力从9.9 mN线性增加到117.2 mN,比冲从1269s台阶上升到3492 s,束流发散角从30.7°下降到26.8°并趋于稳定,各工作点矢量偏角小于1.5°,束流平直度大于0.75,栅极稳定化处理是控制栅间距一致性的重要方法,采用应力释放钼安装环热设计后栅极间距极差得到有效控制,最大下降百分比为90%,本研究为离子推力器多模式化设计及在轨应用工程研制提供参考.

In view of the application requirements of electric propulsion system for China’s asteroid deep space exploration mission,the overall scheme is designed,an ion thruster prototype model is established by using a four-ring-cusp field discharge chamber,30-cm beam current extraction diameter three-grid ion optics system.Reasonableness and compatibility of discharge chamber and grid design are verified experimentally and theoretically.The test results are shown below.The ion thruster can operate steadily over an input power envelope of 277-3120 W,thrust increases linearly from 9.9 to 117.2 mN,specific impulse rises from 1269 to 3492 s,the beam divergence angle drops from 30.7°to 26.8° and stabilizes above a certain power value,the thrust vector angle is less than 1.5° and beam flatness parameter is greater than 0.75 at different operating points.The maximum percentage reduction in grid gap aberration is 90% with the strain relief molybdenum mounting ring thermal design.This research provides a reference for multi-mode ion thruster design and in-orbit engineering applications.