爆震燃烧横向声振现象的机理研究

Exploring Mechanism of Phenomena of Transverse Acoustic Oscillations of Detonation Combustion

发展了一种新型低能量（50mJ）单级起爆系统，在内径为60mm的脉冲爆震发动机模型上，采用汽油／空气混合物，成功地进行了两相脉冲爆震发动机原理性实验，所测量的爆震波压力接近充分发展的爆震波。通过实验发现，爆震反应区中存在频率范围为10～12kHz以爆震管内径为特征尺度的横向声振现象。当对爆震波时间一压力曲线进行该频段范围的带阻滤波时，爆震波峰值压力显著降低，说明该横向声振现象对于爆压等特性参数具有较为明显的影响作用。根据爆震波的横向声振机制，提出了在爆燃向爆震转变过程及爆震自持过程中，通过抑止或促进这种横向声振机制来实现对爆震波及其转变过程进行控制的方法。

Aim. We have gradually come to believe that recent progress in PDE（Pulse Detonation Engine） research has made it quite feasible to let missiles, UAVs and UCAVs to employ two-phase PDE. We now report the results of our exploratory study on methods of controlling detonation waves on a two-phase PDE model. In the full paper, we explain in some detail our exploration; in this abstract, we just add some concise remarks to the two topics of our explanation： （A） experimental method and setup; （B） experimental results and analysis. In topic A, Fig. 1 in the full paper shows the schematic of our experimental two phase PDE model, 60mm in inside diameter, which includes the well-known Shchelkin spiral. In topic B, a proof-of-principle experiment of a two-phase PDE was successfully carried out by using liquid C8H18/air mixture with low-energy system （total stored energy of 50 mJ） and then a new onestep detonation initiation method was developed. Also in topic B, experimental results, summarized in Figs. 2 and 3, show that the measured detonation wave pressure was very close to that of fully developed detonation. Again in topic B, Figs. 3 through 6 in the full paper show clearly the very important fact that transverse acoustic oscillations with its frequency range from 10 kHz to 12 kHz occur in detonation reaction zone, which has the characteristic scale of detonation tube inner diameter. Still in topic B, when band block filter of the band scope was carried out on a detonation time-pressure curve, detonation wave peak pressure decreased significantly, implying that the oscillations have an obvious effect on detonation characteristic parameters such as detonation peak pressure. Finally, in summary, based on the mechanism of transverse acoustic oscillations of detonation wave, a method has been presented here to control both detonation wave and deflagration to detonation transition （DDT） by suppressing or promoting transverse acoustic oscillations of detonation wave during DDT process and detonation wave sustained propagation.