增强型喷射器对爆轰波DDT过程的影响

Influence of an enhanced injector on DDT process

在激波、火焰及射流同时存在的流场中,组织燃烧转爆轰过程是脉冲爆震发动机实现点火、起爆的关键问题。设计一类喷射器,采用C_2H_2/O_2/Ar反应,数值验证了该喷射器能增强爆震室燃料燃烧转爆轰的可行性,并讨论了流场中热点的点火机制。结果显示:该装置在流场中可激发不稳定性,产生漩涡,加速能量、质量的交换。流场产生热点,促进火焰速度加快,追赶前导激波。喷射器位置影响前导激波的运动速度。在一定范围内,前导激波速度越大,碰撞产生的热点越容易激发燃烧转爆轰过程。

In the flow where the shock wave, the flame and the jet exist simultaneously, the successful process of deflagration to detonation transition (DDT) is the key to the pulse detonation engine (PDE). One kind of injector was designed, and the feasibility of enhancing deflagration to detonation transition in detonation chamber was validated by numerical simulation based on C2H2/O2/Ar reaction. The mechanism analysis of the hot spot initiating detonation was made. The device can excite instability in the flow field, generate eddies, and accelerate the exchange of energy and mass. The flow field generates hot spots, which accelerate the flame speed and catch up with the leading shock wave. The position of the ejector affects the velocity of the leading shock wave. Within a certain range, the higher the velocity of the leading shock wave is, the easier the hot spot generated by the collision will trigger the combustion-to-detonation transition process.