注氧位置对电弧加热等离子体发生器性能的影响

Simulation of Flow Field of Arc-Heated Nitrogen/Oxygen Plasma Generator

等离子体发生器被广泛应用于再入飞行器热防护地面试验中,而对等离子体发生器的数值仿真可以预估发生器性能,对发生器的设计工作起到一定作用。因此本文通过耦合磁流体力学控制方程和N-S方程,对自主设计的氮氧等离子体发生器进行了数值仿真。仿真获得了发生器内部的温度场与速度场,以及氮氧的组分分布以及出口气流部分气动热力学参数,并讨论了注氧位置对发生器性能的影响。仿真结果表明,在发生器通道内,电弧的热能转化为工质内能,工质通过收缩-扩张型喷管以后将部分内能转化为动能,达到超音速,同时注氧位置前置可以使射流混合更充分,获得更好的射流性质。

The flow-field of the lab-built arc-heated nitrogen/oxygen plasma generator,a key component of the arc-heated plasma wind tunnel,was mathematically modeled,theoretically analyzed by solving the magneto-hydrodynamics equations based on the magnetic vector potential and numerically simulated with software FLUENT. The temperature field,velocity field,mass fraction distributions of N2/O2,and total specific enthalpy at the outlet were evaluated. The impact of the O2 injection position on the performance of the plasma generator was investigated. The simulated results show that the thermal energy of the gases,originated from the arc heating,was converted into supersonic kinetic energy by compression/expansion of Lawal Nozzle; and that the O2 injection in front of the throat improves the mixing uniformity of N2/O2 andplasma jet properties. We suggest that the simulated results be of some technological interest in design of the arc-heated plasma generator.