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

研究的最终目标是开发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，并且易于提高工作频率。为此，我们在一个截面为矩形的燃烧室上进行了基本的研究。爆轰起爆方式基本为障碍型。然而，障碍物是平行于燃烧室流动方向的几块板，因此在燃气排气阶段和充气阶段障碍物的流动阻力较小。在研究中，我们主要对障碍物板的形状和结构进行了优化。特别是利用多种压力传感器和离子探针，对裂纹波的产生、传播和火焰的加速进行了详细研究。在实验中，我们使用氢-氧-氩混合气体和氢-空气混合气体，这些气体的等效比保持一致。研究发现，火焰的剧烈加速和随后的爆燃-爆轰过渡发生在燃烧室侧壁附近。障碍物板的分离距离和横截面形状对爆燃-爆轰过渡过程有显著影响。在对障碍物板条件进行优化后，我们在氢气-空气混合气中成功地引发了爆轰。

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.