电弧推力器约束通道内流动特性数值模拟

约束通道对电弧推力器的性能有着重要的影响，文章采用基于局域热力学模型（LTE）的数值模拟方法对中等功率电弧推力器内等离子体流动进行了数值模拟，考察了电流、入口压力、约束通道尺寸及不同推进剂对约束通道内等离子体流动的影响，分析了约束通道内非均匀流动现象，最后对推力器的性能、效率等进行了讨论。计算结果表明，随着电流的增加电弧高温区变粗变长，随着入口压强的增加电弧高温区半径减小而长度增加，随着约束通道半径的减小电弧高温区变得细长，随着约束通道长度的增加高温区的长度增长而半径无明显变化，氢气的高温区明显小于氮气和氩气；约束通道内只有小部分气体通过高温区被电离，大部分气体沿着壁面附近的低温区流动；约束通道内焦耳热约占总焦耳热的60%~80%，主要受约束通道长度影响。

Numerical simulation of the flow characteristics within the constrictor of an arcjet thruster

The constrictor is a key part of arcjet thrusters, which has a significant effect on the performance and efficiency of the arcjet thruster.A modeling study was performed to investigate the plasma flow through the constrictor of medium power arcjet thrusters based on the local thermal equilibrium (LTE) assumption. The effects of the current, inlet pressure, constrictor dimensions and different propellants on the plasma flow characteristics, including the nonuniform flow characteristics, within the arcjet constrictor were studied. And the effects of the current, inlet pressure and constrictor dimensions on the performance and efficiency were further presented. The numerical results show that the hot arc region radius and length increase with the increase of the current; with the increase of the inlet pressure, the radius of hot arc region decreases but length increases;with the decrease of the constrictor radius, the hot arc region radius decreases while length increases; the hot arc region length increases and radius shows no significant changes with the increase of the constrictor length; and the hot arc region with hydrogen as the propellant is apparently smaller than those with nitrogen and argon as the propellant. It is also found that a small amount of the gas passes through the hot arc region where the gas is ionized, and most of the gas flows through the low temperature region near the wall. The Joule heating within the constrictor approximately accounts for 60 %-80 % of the total Joule heating within the arcjet thruster, mainly affected by the constrictor length.