Abstract A multi-channel gliding arc (MCGA) plasma was used to enhance ignition and combustion of ethylene fuel in a cavity-based scramjet combustor with an inflow speed of Ma = 2.92. Simultaneously electro-optical diagnostics were conducted to show characteristics of the MCGA-enhanced ignition and combustion, as well as simultaneous schlieren and CH* emission images. The voltage and current measurements demonstrate that the average power of the MCGA declines from 1824 W of an ignition state to 1196 W of a stable combustion state. Several flame kernels produced simultaneously by the power spikes of the MCGA can be merged to enhance the ignition, resulting in a faster speed of flame propagation (48% reduction in the flame propagation time) and a shorter ignition time (61% reduction in the ignition time) compared to the ignition by a single-channel gliding arc. The enhancement effect of the MCGA on combustion is more significant with an increasing global equivalence ratio. The wall pressure of the scramjet combustor in the presence of the MCGA at a global equivalence ratio of 0.22 is comparable to the pressure at a global equivalence ratio of 0.32 in the absence of the MCGA. The main reasons for the significant combustion enhancement may be the re-ignition of the cavity flame by the MCGA plasma, adding extra heat and reactive species to the flame in the shear layer.

中文翻译：

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多通道滑翔电弧等离子体在腔基超音速燃烧室中的点火和燃烧增强

摘要 采用多通道滑翔弧(MCGA)等离子体在流入速度为Ma = 2.92的腔式超燃冲压发动机燃烧室中增强乙烯燃料的点火和燃烧。同时进行光电诊断以显示 MCGA 增强点火和燃烧的特征，以及同步纹影和 CH* 排放图像。电压和电流测量表明，MCGA 的平均功率从点火状态的 1824 W 下降到稳定燃烧状态的 1196 W。由 MCGA 的功率尖峰同时产生的几个火焰内核可以合并以增强点火，与单通道滑动电弧点火相比，火焰传播速度更快（火焰传播时间减少 48%）和点火时间更短（点火时间减少 61%）。随着全局当量比的增加，MCGA对燃烧的增强作用更加显着。在 MCGA 存在下 0.22 的全局当量比下，超燃冲压发动机燃烧室的壁压力与没有 MCGA 时的 0.32 全局当量比下的压力相当。显着增强燃烧的主要原因可能是 MCGA 等离子体重新点燃了空腔火焰，为剪切层中的火焰增加了额外的热量和反应性物质。在 MCGA 存在下 0.22 的全局当量比下，超燃冲压发动机燃烧室的壁压力与没有 MCGA 时的 0.32 全局当量比下的压力相当。显着增强燃烧的主要原因可能是 MCGA 等离子体重新点燃了空腔火焰，为剪切层中的火焰增加了额外的热量和反应性物质。在 MCGA 存在下 0.22 的全局当量比下，超燃冲压发动机燃烧室的壁压力与没有 MCGA 时的 0.32 全局当量比下的压力相当。显着增强燃烧的主要原因可能是 MCGA 等离子体重新点燃了空腔火焰，为剪切层中的火焰增加了额外的热量和反应性物质。