基于PIC/MCC/DSMC方法霍尔推力器热分析

Thermal Analysis of Hall Thruster by PIC/MCC/DSMC Method

关键词:  霍尔推力器  PIC/MCC/DSMC  热分析

Key words:  Hall thruster  PIC/MCC/DSMC  Thermal analysis

摘要:

以提高霍尔推力器性能和使用寿命为目的对霍尔推力器进行了热分析。建立了等离子体在通道陶瓷壁面和阳极的能量沉积计算模型，并将模型耦合到PIC/MCC/DSMC流场计算程序中，计算加速通道壁面上的能量沉积分布。将计算得到的壁面能量沉积作为霍尔推力器温度计算的热流边界条件，考虑结构间的热传导与热辐射，计算温度分布。为了考察壁面的热流分布方式不同对温度场的影响，在总热流相同的情况下，将通道热流假定为线性分布与平均分布，计算霍尔推力器的温度分布。结果表明，壁面能量沉积占总功率的20.4%，陶瓷壁面能量沉积沿轴向位置先增大后减小，最大值在电离区。阳极的能量沉积，沿径向在中间位置达到最大，两端靠近壁面处较小。三种热流边界条件下的温度结果表明，三者最高温度都为700K左右，但高温位置不同，PIC热流边界条件下，最高温在电离区，而线性与平均热流边界条件下，高温区分别在出口区与近阳极区。通过与实验结果比较表明，PIC计算热流边界条件下高温区温度与测量者吻合更好，误差小于0.8%。

Abstract:

To improve the performance and lifetime of the Hall thruster，the thermal analysis is performed. A plasma energy deposition model is developed through analyzing the energy exchange during particles-wall interaction. It is coupled to the PIC/DSMC/MCC hybrid method which is used for flow field simulation for the calculation of the energy deposited onto the channel wall. The thermal characteristic of the Hall thruster is calculated by combining heat conduction and radiation with the calculated heat flux boundary condition. To examine the influences of different heat flux distribution styles on the temperature field，the thermal distribution of Hall thruster is calculated with the PIC/DSMC/MCC calculated heat flux，the linear and average distribution of heat flux，respectively. The results show that the proportion of the total energy deposited on walls is 20.45% to the power of Hall thruster. The energy deposition on the channel wall reaches its maximum at the ionization zone first and then is reduced at the exit zone. The energy deposition onto the anode is small at the two ends and is at a maximum at the middle zone along the radial direction. The highest temperature is 700K at three heat flux conditions，but it happens at different positions. It is at the ionization zone under the PIC/DSMC/MCC flux condition，whereas it is located at the exit zone or the anode zone under the linear or average flux condition. The temperature with the PIC/DSMC/MCC heat flux boundary condition is found to be more reliable by comparing the results of the simulation with the experimental results，in which the error is below 0.8%.