重粒子碰撞对霍尔推力器通道等离子体影响数值研究

Numerical Study for Impact of Heavy Particle Collisions on Plasma in Channel of Hall Thruster

为了研究重粒子碰撞对霍尔推力器通道等离子体影响,采用PIC/MCC/DSMC混合法对放电通道工作过程进行数值仿真研究。建立放电通道二维数值仿真模型,模型中对重粒子碰撞进行重点考虑。估算了通道内各粒子碰撞下的平均自由程,并针对重粒子碰撞单一变量开展了2个仿真模型计算,并对结果进行了对比分析及验证。结果表明:重粒子碰撞对通道内离子数密度分布影响较大,主要表现为离子数密度分布在电离区更为均匀,离子数密度峰值下降6.9%;离子轴向速度影响较小,出口处离子轴向平均速度下降1.3%。与实验结果对比验证,重粒子碰撞因素使仿真结果与测试值之间误差由9.0%缩小到7.3%。

To investigate the impact of heavy particle collisions on plasma in discharge channel of Hall thruster,simulation results on the working process of discharge channel are presented by PIC/MCC/DSMC hybrid method. A two-dimensional axisymmetric model is developed,which particularly takes into account the processes of momentum collision and charger exchange collision among particles in the model. The mean free paths of particle collisions in the discharge channel are estimated,and then two numerical models are simulated with the single variable of heavy particle collisions. The results are compared and verified finally. It indicates that the ion density distribution in discharge channel is influenced by heavy particle collisions,which are summarized as follows： the plasma density in the ionization region is more uniform,and the plasma density peak decreases by 6.9%. Ion axial velocity is barely affected,and the average axial velocity of ions at the exit decreases by 1.3%.The error between the simulation and real experiment is narrowed from 9.0% down to 7.3% due to the heavy particle collisions.