大气压条件下高焓空气等离子体流场特性及应用

评估和鉴定高超声速飞行器防热材料使用性能，需要在能够模拟飞行气动热环境的高焓设备中进行大量地面试验。详细介绍了一种能够运行在大气压条件下的电感耦合等离子体设备，该设备能够产生多种气体（空气、氮气、二氧化碳、氩气）的等离子体射流，运行功率范围为27~85.5 kW，最大运行效率可达77.9%。通过对30 mm的亚声速喷管出口8 mm处空气等离子体流场参数高精度重构和发射光谱测试研究，获得了气体温度和光谱发射强度沿径向的分布，等离子体的焓值范围为8.54~22.2 MJ/kg，驻点热流最高可达721 W/cm²。选定2个试验状态对典型防热材料C/SiC进行烧蚀氧化考核试验，并通过与国内外同类设备比较，表明该大气压感应耦合等离子体设备达到国际先进水平，完全具备开展高超声速飞行器防热材料性能改进地面模拟试验的能力。

Characteristic and application of high enthalpy air plasma flow field under atmospheric pressure

To evaluate the performance of thermal protection materials of hypersonic vehicles, it is needed to conduct ground tests in the high enthalpy facilities for simulating the aerothermal environment. A new inductive coupled plasma torch facility is introduced. The facility can operate under atmospheric pressure, and can produce plasma jets of air, nitrogen, carbon dioxide and argon, with the operation power ranging from 27 to 85.5 kW, and the maximum operating efficiency being about 77.9%. The parameters of the plasma flow field at the distance 8 mm away from the subsonic nozzle exit of the width of 30 mm is characterized based on high precision diagnostic of air plasma and emission spectroscopy test. The distribution of electron temperature and spectral emission intensity along the nozzle radial direction are obtained. The torch is found to induce a total enthalpy ranging from 8.54 to 22.2 MJ/kg, and the maximum heat flux at the stagnation point reaches 721 W/cm². A comparison of our facility with similar facilities at home and abroad and ablation test of carbon fiber reinforced silicon carbide (C/SiC) under two typical test conditions show that the inductive coupled plasma torch facility can reach the international advanced level, and can be used for ground simulation tests for performance improvement of thermal protection materials of hypersonic vehicles.