纯碳/碳材料烧蚀对飞行器等离子体流场的影响

The Influence of Blated Products of Pure Carbon/carbon Materials on Plasma Flow Field around Aircraft

高速飞行器表面的防热材料在气动加热产生的高温下会分解烧蚀,烧蚀产物进入空气边界层流场后,与流场中的高温空气进行复杂化学反应,对飞行器周围空气流场中组分浓度和等离子体分布产生影响。通过高频等离子体风洞,采取高频感应加热的方式产生超音速高温气流,在相同外形的纯碳碳材料模型和铜制水冷模型周围形成高温绕流流场。利用朗缪尔探针对距离模型不同高度位置的电子数密度进行测试,试验结果表明:当纯碳/碳材料模型处于明显的烧蚀状态时,烧蚀产物会对流场中的电子数密度产生影响,电子数密度低于铜质水冷模型纯空气绕流流场的电子数密度;纯碳/碳材料模型的多个试样在发生烧蚀后的流场电子数密度均随着质量烧蚀速率的增加而减小;纯碳/碳材料烧蚀产物仅影响距离壁面一定距离流场的电子数密度,远离壁面的流场中电子数密度与纯空气流场接近。

The heat-resistant materials on the surface of high-speed aircraft may be decomposed and ablated under the high temperature generated by aerodynamic heating.After the ablated products enter the flow field,they react with the high-temperature air in the flow field,thus affecting the component concentration and plasma distribution in the air flow field around the aircraft.A high-temperature supersonic air flow is generated by high-frequency induction heating in a high-frequency plasma wind tunnel.A high-temperature flow field is formed around a pure carbon-carbon material model and a water-cooled copper model with the same shape.The electron number density at the different heights of distance model was measured by using Langmuir probe.The experimental results show that,when the pure carbon-carbon material model is in an obvious ablation state,the ablated products affect the electronic number density in the flow field,which is less than that in the pure air flow field of the water-cooled copper model;and the electronic number density in the flow field of multiple samples of the pure carbon-carbon material model after ablation decreases with the increase in the mass ablation rate.The ablated products only affect the electron number density in the flow field at a certain distance from the wall,and the electron number density in the flow field far away from the wall is close to that in the pure air flow field.