Jet scale affects the mixing and combustion of fuel and inflow. With the increase in the scale of scramjet combustors, the study of large-scale jets is particularly significant. The effects of jet scale on flame stability in scramjet combustors were studied by direct-connect combustion experiments. In this paper, the flame distribution characteristics of different jet scales were compared by using similar jet/inflow momentum ratios. The inflow Mach numbers were 2.4 and 3.0, and the total temperature was 1265 K and 1600 K, respectively. The results show that, when the equivalence ratio increases, the combustion intensity increases. Under the condition of same momentum ratio, the increase of jet scale is conducive to fuel injection into the core mainstream, increasing heat release, and the flame stabilization mode will change from cavity stabilization mode to jet-wake stabilization mode. Increasing the distance between jet orifices is not beneficial to combustion, and may even lead to blowoff.

中文翻译：

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射流结垢对超燃冲压发动机燃烧室火焰稳定性影响的研究

水垢影响燃料和流入的混合和燃烧。随着超燃冲压发动机燃烧室规模的不断扩大，对大型射流的研究显得尤为重要。通过直接连接燃烧实验研究了射流规模对超燃冲压发动机燃烧室火焰稳定性的影响。在本文中，使用相似的射流/流入动量比比较了不同射流尺度的火焰分布特征。流入马赫数为 2.4 和 3.0，总温度分别为 1265 K 和 1600 K。结果表明，当当量比增加时，燃烧强度增加。在相同动量比的情况下，射流规模的增加有利于燃料向堆芯主流喷射，增加热量释放，火焰稳定模式将从空腔稳定模式转变为射流尾流稳定模式。增加射流孔之间的距离不利于燃烧，甚至可能导致喷出。