旋转爆震发动机爆震波建立过程实验研究

Experiment Research on Establishing Process of

关键词:  旋转爆震波  氢-空气混合  DDT过程  小能量点火

Key words:  Rotating detonation wave  H2/Air mixtures  Deflegration to detonation transition  Low energy ignition

摘要:

为了深入研究旋转爆震发动机爆震波建立过程及形成机理，采用小能量火花单次点火的方式进行了一系列旋转爆震发动机起爆实验。发动机采用环缝-喷孔对撞式掺混方式，燃料为H2，氧化剂为空气，实验成功起爆旋转爆震波，并连续旋转稳定传播，爆震波传播频率为5.09 ~ 6.45kHz，传播速度为1286 ~ 1644.8m/s。在发动机稳定工作过程中，集气腔与燃烧室相互影响，二者处于平稳的动态平衡。其次，通过对旋转爆震波起爆过程详细分析发现，点火形成的初始火焰在环形燃烧室经历一个类似DDT的火焰发展过程，成功转变为爆震波，且从点火到爆震波建立之间的火焰发展传播过程和时间间隔均表现出很强的随机性。此外，为验证小能量火花点火的可靠性，还进行了小能量点火重复性实验，发现在稳定工况条件下采用小能量点火成功率最高可达100%，各组旋转爆震波传播速度在1440m/s附近波动。

Abstract:

In order to understand the establishing process and formation mechanism of the rotating detonation wave，an experimental study on the rotating detonation engine with the slot-orifice impinging injection method was presented. Reactants were gaseous H2-Air mixtures and ignited for once by a low-energy ignition plug directly. The engine was initiated successfully and rotating detonation wave propagated continuously and steadily in the circumferential direction. The main frequency of the rotating detonation wave is 5.09 ~ 6.45kHz and the velocity is 1286 ~ 1644.8m/s. In the stable operating process，the plenum chamber and the annular combustion chamber interact with each other，and a dynamic equilibrium is built up. Through the detailed analysis on the establishing process of rotating detonation wave engine，it is found that deflagration-to-detonation transition(DDT) was observed in the annular combustion chamber，and the development process of the flame and the DDT time exhibited an obvious randomness. Besides，in order to obtain the success rate of rotating detonation wave initiation with a low-energy ignition plug，repeatability experiments were carried out. The results show that the success rate is up to 100%，and the velocity of rotating detonation wave of every test fluctuates around 1440m/s.