This paper examines the ability of nanosecond repetitively pulsed (NRP) plasma discharges to improve stabilization and extend the blow-off limit of lean premixed methane-air swirl flames at pressures up to 5 bar. The effect of two discharge regimes, NRP glows and NRP sparks, was investigated. The electrical characterization of the discharges was performed and direct images at 60 Hz of the flames, with and without NRP discharges, were collected to assess the effect of the discharges on flame stabilization. Results showed that NRP discharges efficiently extended the lean blow-off and stability limits of premixed methane-air swirl flames, at pressures up to 5 bar. These results were obtained for a ratio of NRP discharge power to flame thermal power of 0.7% or less. Moreover, the peak voltage necessary to maintain constant this power ratio did not increase linearly with increased pressure, even though the reduced electric field should linearly decrease with the pressure. It was also...

中文翻译：

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纳秒级重复脉冲放电提高了高压下甲烷-空气旋流火焰的稀薄稳定性和喷出极限

本文研究了纳秒级重复脉冲（NRP）等离子体放电改善稳定性的能力，并扩展了压力高达5 bar的稀薄的预混合甲烷-空气旋流火焰的吹扫极限。研究了两种放电方式（NRP发光和NRP火花）的影响。进行放电的电学表征，并收集有无NRP放电的火焰在60 Hz时的直接图像，以评估放电对火焰稳定的影响。结果表明，在压力高达5 bar的情况下，NRP排放有效地扩展了预混合甲烷-空气旋流火焰的稀薄吹气和稳定性极限。这些结果是在NRP放电功率与火焰热功率之比为0.7％或更低的情况下获得的。此外，即使减小的电场应随压力线性降低，维持恒定功率比所需的峰值电压也不会随压力线性增加。还...