宽进气道电子回旋共振离子源电磁场和中性粒子计算研究

Calculation Study of Electromagnetic Fields and Neutral Particles of a Wide Inlet Electron Cyclotron Resonance Ion Source

关键词:  吸气式电推进系统  电子回旋共振离子推力器  直接蒙特卡洛模拟  微波电磁场分布  中性粒子分布

Key words:  Air breathing electric propulsion system  Electron cyclotron resonance ion thruster  Direct Monte Carlo simulation  Microwave electromagnetic field distribution  Neutral particle distribution

摘要:

传统10cm电子回旋共振离子推力器（ECRIT）离子源的进气道进气面积小、压强损失大，无法直接应用于吸气式电推进系统（ABEP）。针对该问题，本文提出了抗流槽和栅格两种宽面积进气道方案，基于多物理场仿真软件COMSOL、直接蒙特卡洛模拟（DSMC）方法，研究了不同进气道离子源内的微波电磁场分布、中性粒子分布，并通过实验验证了方案的可行性。研究结果表明：抗流槽和栅格进气道的最优结构分别为抗流槽中段长度4mm、栅格厚度2mm，最优结构下，两者离子源放电室微波能量均不低于传统离子源；传统离子源和栅格进气道离子源的推进剂供给压强均随流量线性增加，传统离子源所需供给压强约为栅格进气道离子源的3.86倍；当推进剂流量为2cm3/min时，栅格进气道离子源可正常工作，所需的推进剂供给压强为0.14Pa；对比相近工况下传统氮工质10cm ECR离子源，栅格进气道离子源工作性能未见明显衰减。

Abstract:

The conventional 10cm electron cyclotron resonance ion thruster （ECRIT） ion source with small inlet surface and large pressure loss cannot be directly applied to the air breathing electric propulsion system （ABEP）.In order to solve this problem， this paper proposes two kinds of wide area inlet schemes， namely， anti-flow slot inlet and grid inlet.Based on the multi physical field simulation software COMSOL and the direct Monte Carlo simulation （DSMC） method， the microwave electromagnetic field distribution and neutral particle distribution in different inlet ion sources are studied， and the feasibility of the scheme is verified through experiments. The results show that the optimal structure of the anti-flow slot inlet and grid inlet is 4mm in the middle of the anti-flow slot and 2mm in the grid thickness， respectively. Under the optimal structure， the microwave energy of the discharge chamber of both ion sources is not lower than that of the traditional ion source.The propellant supply pressure of traditional ion source and grid inlet ion source increases linearly with the flow rate， and the supply pressure required by traditional ion source is about 3.86 times that of grid inlet ion source.When the propellant flow rate is 2cm3/min， the grid inlet ion source can work normally， and the required propellant supply pressure is 0.14Pa. Compared with traditional 10cm nitrogen ECR ion source under similar working conditions， the performance of grid inlet ion source has not obviously declined.