脉冲等离子体推力器烧蚀建模与仿真

Ablation modeling and simulation for pulsed plasma thruster

关键词:  脉冲等离子体推力器  烧蚀模型  磁流体动力学  数值仿真

Key words:  Pulsed plasma thruster  Ablation model  Magnetohydrodynamic  Numerical simulation

摘要:

为了深入地揭示平板型脉冲等离子体推力器(PPT)工作机理,通过对PPT在放电过程中的欧姆加热能量分配分析,建立了基于能量守恒原理的改进烧蚀模型,并对磁流体动力学方程中的能量方程进行了修正。结合LES-6对PPT工作过程进行了一维磁流体动力学数值仿真,获得了PPT的速度分布、放电烧蚀质量和元冲量等参数的变化过程。仿真结果表明,改进模型能正确地反映脉冲等离子体推力器工作过程,仿真得到的出口速度、元冲量与实验值吻合较好,而放电烧蚀质量则相对误差较大；当电容容量变化时,元冲量随放电能量增大呈近似的线性增长关系,放电烧蚀质量随放电能量的增大单调增加且呈非线性关系。

Abstract:

To further reveal the working mechanism of Pulsed Plasma Thruster (PPT), the distribution of ohmic-heating energy was analyzed, and an improved ablation model was proposed based on conservation of energy and the energy equation of magnetohydrodynamic (MHD) equations revised. The working process of LES-6 PPT was simulated by use of the one-dimensional MHD program and the temporal variation of some parameters such as the velocity map, discharge ablation mass and impulse bit have been obtained. The results exhibit that the improved model can correctly reveal the working process of PPT and the simulated values of the exit velocity and impulse bit fit well with the experimental values while that of discharge ablation mass shows large error. It is also shown that the impulse bit almost increases linearly with the discharge energy and discharge ablation mass increases with a non-linear correlation while the capacity of the capacitors varies.