磁零点及通道宽度对霍尔推力器性能影响的数值研究

Numerical Study on Effects of Zero Magnetic Region and Channel Width on Hall Thruster Performance

关键词:  霍尔推力器  粒子  磁场  放电特性  数值模拟

Key words:  Hall thruster  Particle  Magnetic field  Discharge characteristics  Numerical simulation

摘要:

磁场位形和通道尺度会改变霍尔推力器等离子体放电过程，影响推力器的宏观放电特性。为分析磁场和通道宽度对推力器放电性能的影响规律，针对霍尔推力器轴对称通道结构和放电物理过程建立了2D3V物理模型，采用粒子模拟方法研究了霍尔推力器磁零点磁场位形不同通道宽度的电势、粒子数密度、电子温度、电离速率、比冲及推功比的变化规律。结果表明：在具有磁零点磁场位形下，随着通道宽度增加，通道出口处电势降增加，加速区缩短，离子径向速度减少，壁面腐蚀降低；当磁零点位置在内壁面，推力器通道宽度由14mm增加到16mm时，推力器比冲和推功比增大，推力器放电效率提高；当磁零点位置在通道中轴线或外壁面，且通道宽度>14mm时，推力器比冲增大，推功比减小，推力器效率下降。

Abstract:

The magnetic field configuration and channel size can change the plasma discharge process of Hall thruster and affect the macro discharge characteristics of the thruster. In order to analyze the effects of magnetic field and channel width on the discharge performance of thruster， a 2D3V model is established based on the axisymmetric channel structure and discharge physical process of Hall thruster. By using particle-in-cell simulation， the variation of potential， particle number density， electron temperature， ionization rate， specific impulse and thrust to power ratio in different channel widths in Hall thruster with zero magnetic field region are studied. The results show that when the zero magnetic field region exists， with the increasing channel width， the potential drop at the exit grows， acceleration zone shortens， ion velocity on the radial direction reduces along with the corrosion. When the zero magnetic field region is located near the inner wall， with the increase of channel width from 14mm to 16mm， the specific impulse and thrust to power ratio of the thruster increase by a certain amount， the discharging efficiency of the thruster is enhanced. When the zero magnetic field region is located near the central axis or the outer wall， while the channel width exceeds 14mm， the specific impulse increases， but the thrust to power ratio of the thruster decreases along with the efficiency.