Investigation of Detonation Initiation by Obstacle Plates Parallel to Flow for Pulse Detonation Engines

本研究的最终目标是研制一种新型的脉冲爆震发动机燃烧室，该燃烧室可以使用空气作为氧化剂，并且可以很容易地使工作频率更高。为此，我们在一个截面为矩形的燃烧室上进行了基础研究。起爆方式基本上为障碍型。然而，在燃烧排气阶段和气体补充阶段，障碍物是平行于燃烧室流动方向m的多个障碍物，障碍物的流动阻力较小，本文主要对障碍物的形状和配置进行了优化。特别是利用多种压力传感器和离子探头，对冲击波的产生、传播和火焰的加速过程进行了详细的研究。在实验中，我们使用了氢-氧-氩混合气体和氢-空气混合气体，它们的当量比保持一致。结果表明，燃烧室侧壁附近发生了强烈的火焰加速和随后的燃烧转爆轰过程。障碍板的间距和截面形状对燃烧转爆轰过程有显著影响。经过对障碍板条件的优化，成功地在氢气-空气混合气体中起爆。

The final objective of the research is to develop a new combustor for a pulse detonation engine where we can use air as the oxidizer and easily make the operation frequency high For the objective, we carried out fundamental studios on a combustor whom cross section was a rectangle. The initiation method of detonations is basically obstacle type. However, the obstacles are several plates parallel to the flow direction of the combustor m that the flow resistance of the obstacles is small during the burned-gas-exhaust phase and the gas-recharge phase.In the research, we mainly optimized the shape and configuration of the obstacle plates. Especially, the generation and propagation of shack waves and the acceleration of flames were investigated in detail with many pressure transducers and ion probes. In the experiments, we used hydrogen-oxygen-argon gas mixtures and hydrogen-air gas mixture, where the equivalence ratio was kept unity. It was found that the intense acceleration of flames and subsequent deflagration-to-detonation transition occurred in the vicinity of the side wall of the combustor. The separation distance and cross-sectional shape of the obstacle plates were hind to have significant influences on the deflagration-to-detonation transition process After some optimization of the obstacle-plate conditions, we successfully initiated detonations in the hydrogen-air gas mixture.