多循环脉冲爆轰发动机外流场的实验研究

利用内径为30mm,长度为1000mm的爆轰管,对多循环脉冲爆轰发动机外流场进行研究.爆轰管内充满氢气-氧气-氮气预混气,采用底端中心点火.实验中采用YA-16高速阴影系统,拍摄了爆轰外流场的阴影照片.根据实验结果,分析了外流场的动力学结构和悬吊激波产生的动力学机理,讨论了两次循环管外流场结构间的差异.第一次循环中的爆轰波溢出爆轰管后,斜压效应和Helmholtz不稳定导致涡环的产生,涡环形状的变化又引起悬吊激波的角度变化,在此过程中引导激波始终为球面形状,在第二个循环中的相应时刻,激波前的气体是向外流动的,导致引导激波逐渐成为葫芦形状.

Experimental study on the external flow flied of multi-cycle pulse detonation engine

Multi-cycle pulse detonation engine(PDE) tests in PDE tube whose inner diameter and length is 30mm and 1000mm respectively,filled with H2-O2-N2,had been performed with central ignition in the end plane.The YA-16 high-speed shadowgraph system was adopted in test to obtain the consequential clear shadowgraphs of the external flow field.Based on the experimental results,the dynamic structure of the external flow filed and dynamic mechanism of the suspended shock was elucidated.The difference of the flow pattern in the external flow fields between the first cycle and second cycle was also discussed.After the donation wave exited the tube during the first cycle,the vortex ring was induced by baroclinic effect and Helmholtz instability and the angle of the suspended shock varied with the modification of the shape of the vortex ring.The shape of leading shock was always spherical during the first cycle,but it became gourd-shaped because of the directional moving gas in front of it during the second cycle.