霍尔推力器磁屏蔽磁场设计及通道结构优化仿真研究

Simulation Study on Magnetic Shielding Field Design and Channel Structure Optimization of Hall Thruster

关键词:  霍尔推力器  磁屏蔽磁场构型  通道结构  软磁材料  数值模拟

Key words:  Hall thruster  Magnetic shielding configuration  Channel structure  Soft magnetic materials  Numerical simulation

摘要:

高能离子轰击引起的霍尔推力器通道壁侵蚀是限制推力器寿命的重要因素。应用磁屏蔽技术可以有效减轻侵蚀，但推力器性能相较传统结构则可能会降低。为设计合理的磁屏蔽磁场并分析通道长度和壁面布置软磁材料对磁屏蔽效果的影响，采用粒子模拟的方法，对霍尔推力器通道内的放电过程进行建模仿真，建立并优化了不同通道长度下的磁屏蔽磁场位形，研究了内外壁面不同位置布置软磁材料对磁屏蔽磁场通道放电特性的影响。结果表明：短通道的磁屏蔽位形可以减少壁面侵蚀和提高推力器性能，随着通道长度从30mm缩短至20mm，离子径向速度降低50%，比冲增加7.78%，阳极效率提高9.1%，推力增加8.3%；附加的磁性材料可以有效地优化磁屏蔽磁场位形，当软磁材料位置向放电通道出口移动时，峰值电子温度降低，离子入射角逐渐减小。当软磁材料放置在距离阳极17.5mm处时，推力增加2.9%，离子径向速度和离子入射角均较小，将有效减少壁面侵蚀。

Abstract:

The channel wall erosion of Hall thruster caused by high-energy ion bombardment is an important factor limiting thruster lifetime， and the application of magnetic shielding configuration can effectively mitigate the erosion. However， magnetic shielding configuration could reduce the performance of the Hall thruster compared to the traditional structure. In order to design a reasonable magnetic shielding magnetic field， and analyze the influence of channel length and wall arrangement soft magnetic materials on the magnetic shielding effect， the particle-in-cell simulation method is applied to study the plasma discharge process in the channel. The magnetic shielding configuration is established and optimized by adjusting channel length and arranging additional magnetic material along the wall. The results show that magnetic shielding configuration with short channel can achieve less erosion and higher performance. When the channel length is shortened from 30mm to 20mm， the ion radial velocity is reduced by half， the specific impulse increases by 7.78%， the anode efficiency increases by 9.1% and the thrust increases by 8.3%. The additional magnetic material can effectively optimize the magnetic shielding configuration. When the soft magnetic material position moves toward the discharge channel exit， the peak electron temperature decreases， the ion incident angle gradually decreases. When the soft magnetic material is placed 17.5mm from the anode， the thrust increases by 2.9%， both the ion radial velocity and the ion incident angle are minimal， and the wall erosion is expected to be reduced.