低功率电弧加热发动机内流动、传热与传质的数值计算

Modeling Study on Flow,Heat Transfer and Mass Transfer in a Low Power Arcjet Thruster

为了获得电弧加热发动机内部流动、传热与传质的一些基本规律,采用基于局域热力学平衡假定的物理模型,对不同气体、工况和发动机进行了研究。结果表明,电弧加热发动机内的气体在约束通道内由亚声速加速到超声速,轴向速度在约束通道出口下游附近达到最大值,然后随着轴向距离的增加速度逐渐降低;电弧加热发动机内气体加热主要发生在阴极下游以及约束段附近,最高温度出现在阴极尖下游;在喷管的扩张段,由于气动膨胀作用以及焦耳热的影响逐渐降低,气体温度逐渐下降。

To obtain the basic rules of the flow, heat transfer and mass transfer in the arcjet, aphysical model based on local thermodynamic equilibrium （LTE） assumption was used to study thearcjet flow with different gases, different working conditions and different thrusters. The resultsshowed that the gas accelerated from subsonic speed to supersonic speed in the constrictor. The axialvelocity reached the maximum near the downstream of the constrictor and then decreased with the in-crease of the axial distance. The arc heating occurred mainly in the downstream of the cathode andconstrictor. The highest temperature appeared in the downstream of the cathode tip. In the expan-sion of the nozzle, the gas temperature gradually decreased due to the aerodynamic expansion andless Joule heating.