高超声速流动中电子密度测量方法和应用研究

高超声速飞行器流场电子密度诊断是解决通讯中断的关键问题，在能够模拟再入飞行速度环境的高焓激波风洞中如何发展电子密度测量技术，提高测量精度，对通讯中断问题的研究有着重要的影响。高焓激波风洞试验时间短、流动速度快、激波强度大、气流温度高的测试环境对发展电子密度测量技术提出了诸多技术难题，尤其是复杂外形边界层、尾迹区等局部电子密度诊断，国内外鲜有相关技术报道和文章发表。本项目针对高焓激波风洞，发展电子密度诊断的静电探针测量技术，解决探针电路高扫描频率所带来的线路噪音干扰问题并优化电路，研究探针材料、探针尺寸对测量的影响规律，实现电子密度的局部诊断并提高精度，在力学所JF10高焓激波风洞中开展典型模型边界层局部电子密度的测量。本项目研究工作的成果，丰富和发展高焓流动测量技术的同时也为通讯中断问题的解决提供地面技术支撑。新型探针技术同时也可应用于其它等离子体诊断环境，尤其是进行瞬态电子密度诊断。

The electron density diagnosis for the flow-field of a high speed aircraft is the key problem to solve the communication blackout. Developing the electron density measurement technology in a high enthalpy shock tunnel, which can simulate the reentry flight speed environment, will have an important impact on the research of communication blackout. The special test environment of a high enthalpy shock tunnel, such as short test time, high flow speed, strong shock wave, high flow temperature, put forward a number of technical problems for the developing of electron density measurement technology, especially for the local region measurement of boundary layer or wake flow. There are little related technical reports or published at home and abroad. This project will develop the electrostatic probe technique for electron density measurement in the high enthalpy shock tunnel. New circuit will be developed in order to reduce the induced noise due to the RC characteristic of coaxial cables when a high frequency swept voltage is applied to the probe. The influencing factors to electron density measurements will also be explored, such as the probe materials and probe size. The final goal is to realize the local region electron density measurement and improve precision. Then the boundary lay electron density measurement of a typical model will be conducted in the JF10 high enthalpy shock tunnel. The achievement of this research will develop and enrich the high enthalpy flow measurement technology. It will also provide technical support for the solving of communication blackout problems. The new probe technique can also be used in other plasma diagnostic environment, especially for transient electron density measurement.