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

本研究的最终目的是研制一种能以空气为氧化剂、易于实现高频工作的脉冲爆震发动机燃烧室。起爆方式基本上是障碍起爆。但由于障碍物是平行于燃烧室流动方向的多个板，因此在燃气排出阶段和燃气回灌阶段障碍物的流动阻力较小，研究中主要对障碍物板的形状和配置进行了优化。特别地，利用多种压力传感器和离子探针，对激波的产生、传播和火焰的加速过程进行了详细的研究。在实验中，我们使用氢-氧-氩混合气体和氢-空气混合气体，其中当量比保持统一。结果表明，火焰的强烈加速和随后的燃烧转爆轰发生在燃烧室的侧壁附近。障碍板的间距和截面形状对燃烧转爆轰过程有显著影响。通过对障碍板条件的优化，我们成功地在氢气-空气混合气体中引发了爆轰。

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.