一种弯曲激波诱导爆震的起爆新方式

New method for detonation initiation induced by curved shock wave

斜楔起爆是斜爆震最典型的起爆方式,增大斜楔角度虽然有利于加速起爆,但会导致爆震波过驱度和燃烧室阻力的增加。为兼顾爆震波的快速起爆和燃烧性能,本文利用弯曲激波系统的灵活性,提出了一种S型壁面起爆方式。该方式既利用内凹壁面压缩来流以促进起爆,又利用外凸壁面膨胀来流降低爆震波的过驱度。由于膨胀波作用于起爆区时可能使爆震波熄爆,因此S型壁面起爆方式的转折点设置显得尤为重要。为此,本文基于弯曲特征线法提出了一种快速计算弯曲爆震起爆位置的方法,以便合理地设置S型壁面转折点。研究结果显示,经过优化的S型壁面起爆方案相较于原有方案,平均推力势增益提高了16.5%、平均总压恢复系数提高了8.3%。

Oblique wedge initiation is the predominant initiation mode for oblique detonation waves. While increasing the angle of the oblique wedge accelerates detonation, it also raises the overdrive degree of the detonation wave and the resistance within the combustion chamber. To simultaneously ensure rapid detonation initiation and combustion performance, we present the S-shaped wall initiation method, making full use of the flexibility of the curved shock wave system. Concave wall compression facilitates detonation initiation, while convex wall expansion mitigates the overdrive degree of the detonation wave. Given that the expansion wave affecting the initiation zone could lead to detonation wave extinguishment, precise adjustment of the turning point for the S-shaped wall initiation method becomes crucial. Thus, employing the method of curved-shock characteristics, we present a calculation approach to determining the initiation position of curved detonation, to establish the turning point of the S-shaped curved wall in a rational manner. Findings reveal that the optimized S-shaped wall initiation scheme leads to a 16. 5% increase in average thrust potential gain and an 8. 3% enhancement in the average total pressure recovery coefficient.