圆柱形霍尔推力器内等离子体数值模拟

Simulation of plasma flow in cylindrical Hall thruster

利用一维磁流体动力学模型,对圆柱形霍尔推力器的放电等离子体进行了数值模拟。考虑了等离子体的电离、中和、碰撞、玻姆扩散及阳极鞘层的影响,由龙格-库塔方法得到离子速度、离子数密度、电子的温度等分布,其与实验结果有很好的一致性。经分析可知,此分布与电磁场的分布、粒子碰撞及电子阻抗等因素有关,并分析了电子温度分布、电子速度与电磁场的关系。结果表明,离子数密度沿通道方向增加,但在出口附近略有下降;而中性粒子数密度逐渐降低;离子速度在出口达到最大值,电子速度在下游有较大的梯度分布。

The plasma inside the cylindrical Hall thruster was simulated by using one-dimension magnetohydrodynamic（MHD） model. Based on considering some influence factors,i, e. the plasma ionization, neutralization, collision, Bohm diffusion and anode sheath etc. were considered. The distributions of ion speed, ion number density and electron temperature, which were coincident with the experimental results, were obtained by means of Runge-Kutta method. These distributions are relevant to electromagnetic distribution, collision and electronic impedance. Finally, the relation of electron temperature distribution and velocity with magnetic field was analyzed. The results show that the ion number density increases, but it drops near exit; the neutral particle number density gradually reduces in the channel; the ion speed reaches the maximum at exit and the electron velocity has the great gradient distribution in the downstream.