Supersonic combustion behaviors in a Mach 2.0 scramjet model combustor were experimentally investigated at stagnation temperatures of 1700–2300 K. An ethylene/methane fuel mixture was used, and the mole fraction of ethylene and the equivalence ratio were varied. Six typical combustion modes were classified based on high-speed imaging of CH* chemiluminescence at 50,000 fps, shadowgraph imaging at 4000 fps and pressure distributions. Ram mode combustion was observed, without thermal choke at the nozzle throat. Mode maps indicated that an increase in the ethylene concentration improved the supersonic combustion performance. Proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) of sequential images of CH* chemiluminescence were also conducted. POD and DMD mode spectra showed large peaks in the frequency range of 100–500 Hz for cavity shear-layer stabilized combustion. Although the power of the spectra decreased, peaks were also observed in the same frequency range for jet-wake stabilized and ram combustion. In the case of the ram combustion mode, the peak heights decreased. The FFT of several primary POD modes and the power spectra of DMD modes showed peaks with similar frequencies. Combustion modes could be classified from these spectra. The fundamental combustion frequencies were captured by the modal decomposition of the high-speed images of CH* chemiluminescence.

在1700–2300 K的停滞温度下，对马赫2.0超燃冲压发动机燃烧室中的超音速燃烧行为进行了实验研究。使用了乙烯/甲烷燃料混合物，并且乙烯的摩尔分数和当量比有所变化。根据50,000 fps的CH *化学发光的高速成像，4000 fps的阴影图成像和压力分布，对六种典型燃烧模式进行了分类。观察到Ram模式燃烧，在喷嘴喉部处没有热阻塞。模式图表明，乙烯浓度的增加改善了超音速燃烧性能。还进行了CH *化学发光顺序图像的正确正交分解（POD）和动态模式分解（DMD）。POD和DMD模式频谱显示了在腔体剪切层稳定燃烧的100–500 Hz频率范围内的大峰值。尽管光谱的强度降低，但在相同的频率范围内也观察到了峰值，以实现喷气尾流稳定和冲压燃烧。在冲压燃烧模式下，峰高降低。几种主要POD模式的FFT和DMD模式的功率谱显示出具有相似频率的峰值。燃烧模式可以从这些光谱中分类。基本燃烧频率是通过CH *化学发光高速图像的模态分解捕获的。峰高下降。几种主要POD模式的FFT和DMD模式的功率谱显示出具有相似频率的峰值。燃烧模式可以从这些光谱中分类。基本燃烧频率是通过CH *化学发光高速图像的模态分解捕获的。峰高下降。几种主要POD模式的FFT和DMD模式的功率谱显示出具有相似频率的峰值。燃烧模式可以从这些光谱中分类。基本燃烧频率是通过CH *化学发光高速图像的模态分解捕获的。