隔离段激波串流场非定常流动机理及高超声速进气道状态监控方法研究

This project aims at establishing the methods of the working condition monitoring for the hypersonic inlet. In this project, several researches would be mainly conducted. Firstly, the current situation and development trend of the shock train all over the world would be investigated and concluded, including the structure of the shock train, the dynamic characteristics, and the flow mechanism. The unsteady characteristics of the shock train motions and its flow mechanism under the real incoming condition would be studied. Secondly, the experimental scheme for the forced shock train oscillation would be carried out based on the characteristics of the fluctuated back-pressure. The characteristics of the shock train motions under the fluctuated back-pressure condition and its flow mechanism would be analyzed. The analytical model for the forced shock train oscillation would be established based on the prior research. Thirdly, the working condition monitoring concepts would be introduced to the hypersonic inlet field: the shock train leading edge detection for engineering application would be figured out; the fault modes for the inlet unstrat would be classified according to the monitoring signals; the control law for the inlet start/ unstart would be explored. At last, the methods of the working condition monitoring and the unstart protection for the hypersonic inlet would be established.

本项目以建立高超声速进气道健康状态监测方法为目标，主要开展以下几个方面的工作。一是充分调研和借鉴国内外学者在激波串形态结构、动态特性、形成机制等方面的研究成果，深入分析接近真实来流条件下隔离段激波串的非定常运动特性和流动机理。二是分析超燃冲压发动机燃烧室的压力脉动特征，设计能够模拟燃烧室脉动反压的隔离段实验方案，研究脉动反压条件下的隔离段激波串非定常运动特性和流动机理，建立隔离段受迫振荡参数的理论模型。三是将发动机状态健康监控的概念引入到对高超声速进气道领域，建立工程实用化的激波串前缘探测方法，对进气道不起动故障模式分类，分析进气道起动/不起动的控制规律，最终建立高超声速进气道状态监测与保护控制策略，形成高超声速进气道状态监控方法。

本项目以建立高超声速进气道健康状态监测方法为目标，在近真实来流条件对激波串形态和非定常运动特性的影响机制、近真实脉动反压条件下激波串非定常运动特性及流动机理、进气道状态健康监控方法等方面取得了一些创新性研究成果。.在近真实来流条件对激波串形态和非定常运动特性的影响机制方面，本项目针对不同飞行速度、高度及飞行攻角条件下的进气道-隔离段一体化外形开展了研究，在变攻角过程中对激波串和隔离段壁面沿程压力变化进行分析，对激波串流场结构、激波串随反压演化过程、壁面压力分布特征有了更为清晰的认识。还对真实非均匀来流条件下的变截面S型隔离段出口施加稳态反压时的自激振荡流动特性进行了研究，对接近真实飞行条件下隔离段激波串非定常运动特性，以及其流动机理有了更为深入的认识。.在近真实脉动反压条件下激波串非定常运动特性及流动机理方面，本项目通过试验与仿真相结合的方法研究了对称型激波串和非对称型激波串的受迫振荡特性。通过试验手段，主要对激波串振荡频率特性、壁面压力振荡特性、激波串振荡幅度等进行研究；通过数值计算手段，主要对激波串振荡过程中形态演化、分离区特性等进行研究。并在简化流场和合理假设的基础上，建立激波串受迫振荡幅度的理论预估模型。发现了脉动反压参数对激波串受迫振荡幅度的影响规律。通过对模型进行试验和仿真结果的验证，结果表明该理论模型能较好的反映激波串振荡幅度随脉动反压参数的变化规律。.在进气道状态健康监控方法方面，基于进气道实际，试验上获得了高超声速进气道超额定不起动现象，分析了不起动流场形成的原因，揭示了进气道迟滞现象形成的内在机理，并提出相应的解决方案。解释了高超声速进气道超额定工况不起动现象的形成机制，指出超额定工况中进气道不起动的本质原因在于分离泡融合现象的延伸；根据融合分离泡的特点，提出了有效的流动控制方案。