基于中红外激光吸收光谱的等离子体高温流场二维测量研究

Accurate measurements for high temperature flowfield are key to evaluate ability of simulating reentry conditions for plasma wind tunnel ground-based testing. Quantitative study for interaction between high enthalpy free stream and specimen surface is a guarantee for optimized, reliable design of thermal protection system. A new mid-infrared laser absorption sensor is developed to obtain ability of detecting typical species in the high temperature plasma flow. Based on the developed sensor, in situ diagnostic technique is built to quantitatively study the high temperature plasma flow for ground-based tests simulating reentry flights. Based on research objects for ground-based tests for Mars/Earth reentry，the main contents are as follows. First, measurements of plasma flow in the arc heater to study inherent law between high enthalpy flow characteristics and operation parameters of arc heater. Second, in situ diagnostics for gas flow from free stream to shock layer. Spatially resolved results along radial and axial coordinate for carbon monoxide, nitric oxide and gas temperature can be measured to study high temperature thermo-chemical characteristics for Mar/Earth reentry. Measurements offer accurate basis to validate and improve numerical modeling for thermos-chemical equilibrium and non-equilibrium flow. The developed technique provides a quantitative approach to understand characteristics of flow field for spacecraft reentry and optimize design of thermal protection system.

高温流场的精确测量是评估等离子体风洞模拟真实再入流场试验能力的关键，自由流与防热材料相互作用过程中气流参数的定量变化是进行热防护系统精细、可靠设计的保证。本项目发展新型中红外激光吸收光谱技术，提升对高温流场典型组分的探测能力，获得高温热化学参数的二维空间分辨结果，建立定量研究模拟再入过程地面试验流场的在线诊断方法。以模拟再入火星/地球大气地面流场为研究对象，主要研究包括：（1）开展对电弧加热器内等离子体气流的测量，获得高焓流场特性与加热器运行参数之间的内在规律；（2）开展自由流过渡到驻点激波层内流场参数的在线诊断，获得火星/地球大气再入关键组分CO、NO浓度和温度沿流场轴向和径向的空间分辨结果，研究高温气流-表面相互作用过程中热化学特性的变化。高温流场的在线测量，为验证和优化高温热化学平衡、非平衡流场数值建模提供了准确试验依据，为了解飞行器再入流场特性和热防护系统优化提供了定量化技术手段。

高温流场的精确测量是评估等离子体风洞模拟真实再入流场试验能力的关键，自由流与防热材料相互作用过程中气流参数的定量变化是进行热防护系统精细、可靠设计的保证。本项目发展新型中红外激光吸收光谱技术，提升对高温流场典型组分的探测能力，获得高温热化学参数的二维空间分辨结果，建立定量研究模拟再入过程地面试验流场的在线诊断方法。以模拟再入火星/地球大气地面流场为研究对象，主要研究包括：（1）开展对电弧加热器内等离子体气流的测量，获得高焓流场特性与加热器运行参数之间的内在规律；（2）开展自由流过渡到驻点激波层内流场参数的在线诊断，获得火星/地球大气再入关键组分CO、NO浓度和温度沿流场轴向和径向的空间分辨结果，研究高温气流-表面相互作用过程中热化学特性的变化。高温流场的在线测量，为验证和优化高温热化学平衡、非平衡流场数值建模提供了准确试验依据，为了解飞行器再入流场特性和热防护系统优化提供了定量化技术手段。