未来宽域飞行包线内提升冲压发动机性能需要依靠先进的燃烧组织策略及发动机系统控制技术，其中高动态频响传感器及作动机构是高性能控制系统FADEC的关键技术之一。稳定可靠、结构简单、非侵入、低耗能、重量轻是冲压发动机在线传感器的基本要求。针对难以开设光学窗口的发动机燃烧室燃烧状态感知需求，本文发展了一种新的内窥式光纤传感器技术，并提出了基于该传感器的超声速燃烧场分析方法。所发展内窥式光纤传感器采用了考虑热容差设计的光纤准直设计方法及独特的热密封结构和方法，基于中国科学院力学研究所的直连式超声速燃烧试验台，开展了50余车超声速燃烧实验热考核，未见明显损伤。同时在来流总温1475K，总压1.68MPa，隔离段入口马赫数2.8的实验条件下开展了超声速燃烧感知实验研究。

  在四组固定当量比和两组变当量比的实验状态下，通过沿程压力分布、一维马赫数分析方法、纹影图像以及OH*与CH*平面自发光成像，对燃烧模态和火焰状态进行了分析和判断。在每一个测点通过光纤分路器分别测量了C₂*自发光和CH*自发光。为了验证内窥式光纤传感器的测量原理，对传感器测量的CH*光信号和平面自发光成像的CH*光信号进行了相关性分析；观察并分析了CH*表征的释热信号在流向和展向的分布特征以及每个测点的释热随时间的演变特性；通过对高频压力信号和CH*光信号进行快速傅里叶变换（FFT），研究了燃烧振荡特性；以C₂*/CH*表征局部当量比，在时间和空间上观察了C₂*/CH*与CH*的关联性，并通过局部窗口的移动相关性分析方法和统计方法计算了CH*相对于C₂*/CH*的滞后时间；基于内窥式光纤传感器和平面成像，分别定义了局部质心和全局质心，研究了质心运动轨迹和燃烧状态的关联性，并通过计算质心的概率分布识别燃烧稳焰模式。

  研究表明，内窥式光纤传感器的燃烧感知能力不亚于开设观察窗口的平面成像测量方法；内窥式光纤传感器CH*光信号可感知燃烧室释热率的时空演变特性；内窥式光纤传感器CH*光信号可感知时域及频域燃烧振荡特性，应用于热声耦合机制研究；内窥式光纤传感器C₂*/CH*光信号可感知局部当量比的时空演变特性，结合CH*光信号应用于混合场与燃烧场关联性研究；提出一种将内窥式光纤传感器用于定义火焰运动轨迹和稳定性的新方法，通过对燃烧稳焰模式识别及其概率统计分析验证了该方法的合理性。

    The improvement of ramjet performance in the future wide-area flight envelope requires advanced combustion organization strategies and engine system control technology. Among them, high-dynamic frequency response sensors and actuators are one of the key technologies of the high-performance control system FADEC. Stable and reliable, simple structure, non-intrusive, low energy consumption, and light weight are the basic requirements of ramjet online sensors. Aiming at the demand for sensing the combustion state in the combustion chamber where it is difficult to open an optical window, this paper develops a new endoscopic optical fiber sensor technology, and proposes a method analyzing supersonic combustion field based on this sensor. The developed endoscope optical fiber sensor adopts the optical fiber collimation design method considering the thermal tolerance design and the unique heat sealing structure and method, more than 50 supersonic combustion experiments have been carried out, and no obvious damage was seen in the endoscopic optical fiber sensor. At the same time, the supersonic combustion sensing experiment was carried out under the experimental conditions of the total incoming temperature of 1475K, the total pressure of 1.68MPa, and the inlet Mach number of the isolation section of 2.8.

    Under the experimental conditions of four sets of fixed equivalence ratios and two sets of variable equivalence ratios, through pressure distribution along the model, one-dimensional Mach number analysis method, schlieren image, and OH* and CH* chemiluminescence imaging, the combustion mode and flame state are analyzed and judged. The C₂* chemiluminescence and CH* chemiluminescence were measured at each measuring point through the optical fiber splitter. In order to verify the measurement principle of the endoscopic optical fiber sensor, the correlation between CH* signal measured by sensor and CH* signal from imaging is analyzed; The distributions of heat release signals represented by CH* were observed and analyzed in the streamwise direction and spanwise direction, and the evolution of heat release at each measuring point with time; The correlation between C₂*/CH* and CH* was observed in time and space by using C₂*/CH* to represent the local equivalent ratio. The lag time of CH* relative to C₂*/CH* was calculated by local window moving correlation analysis and statistical method; Based on the endoscopic optical fiber sensor and planar imaging, the local centroid and the global centroid are defined respectively, the correlation between the movement trajectory of the centroid and the combustion state is studied, and the flame stabilization mode is identified by calculating the probability distribution of the centroid.

    Studies have shown that the combustion sensing capability of the endoscopic fiber optic sensor is no less than that of the planar imaging measurement method with an observation window; The CH* optical signal measured by the endoscopic optical fiber sensor can perceive the temporal and spatial evolution characteristics of the heat release rate of the combustion chamber; The CH* optical signal measured by the endoscopic optical fiber sensor can perceive the characteristics of combustion and oscillation in the time domain and frequency domain, and be used in the study of thermoacoustic coupling mechanism; The C₂*/CH* optical signal of the endoscope optical fiber sensor can perceive the temporal and spatial evolution characteristics of the local equivalence ratio, and can be combined with the CH* optical signal to study the correlation between the mixed field and the combustion field; A new method of using the endoscopic optical fiber sensor to define the trajectory and stability of the flame is proposed. The rationality of the method is verified through the pattern recognition of the flame stabilization mode and its probability statistical analysis.