Ignition characteristics of the long electrode distance high-energy spark igniter (LHSI) in a cavity-stabilized scramjet combustor at low flight Mach has been numerically and experimentally investigated and compared with those of conventional lower energy spark igniter (SI). The effects of ignition and injection schemes on ignition performance were analyzed and the enhancement of greater spark energy were verified. The results show that the widest ignition boundary of SI is observed when the kerosene is injected in far field due to the sufficient evaporation of kerosene droplets and the disturbance caused by upstream cavity. Due to the greater energy deposition by LHSI, the ignition performance is markedly improved and the ignition boundary of combustor is extended from 0.131–0.148 to 0.091–0.224 under the scheme of I1+L2. The increased energy deposition of spark plasma ignites more combustible mixture and enhances the initial combustion, leading to a larger high-temperature zone. This is crucial for ensuring the survival of the flame kernel against dissipation of airflow in the scramjet combustor operating at low fight Mach numbers due to the short duration of spark discharge.

中文翻译：

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低飞行马赫条件下超燃冲压发动机燃烧室中高能火花的点火增强特性研究


对腔体稳定超燃冲压发动机燃烧室中长电极距离高能火花点火器 （LHSI） 在低飞行马赫时的点火特性进行了数值和实验研究，并与常规的低能火花点火器 （SI） 进行了比较。分析了点火和喷射方案对点火性能的影响，并验证了更大火花能量的增强。结果表明，由于煤油液滴的充分蒸发和上游腔的扰动，在远场注入煤油时观察到SI的点火边界最宽。由于 LHSI 的能量沉积更大，在 I1+L2 方案下，燃烧室的点火边界从 0.131–0.148 扩展到 0.091–0.224。放电等离子体的能量沉积增加，点燃了更多的可燃混合物，并增强了初始燃烧，导致更大的高温区。由于火花放电持续时间短，这对于确保火焰内核在以低战斗马赫数运行的超燃冲压发动机燃烧室中防止气流耗散而存活至关重要。