Research On Detonation Initiation By Shock Waves Among The Tubes With Different Diameters

In this paper, single detonation equipment was designed to investigate the mechanism and characteristics of detonation waves initiated by shock waves among the tubes with different diameters. The macro-characteristics and cellular characteristic of detonation waves initiated by shock waves were studied through the experiment. Results indicate that:In the experimental study of the macro characteristics, several parameters were set to investigate the influence of detonation waves initiated by shock waves, such as the Mach number of the shock waves, the ratio of shock tubes diameter, the expansion angles between tubes and the parameters of the reflector. Results show that there are two primary mechanisms about the hot spots which could develop into the detonation. On the one hand, the hot spots are triggered by shock waves which reflected from the Cone and diffraction; On the other hand the hot spots are triggered by shock waves reflected from wall and mach stem. Compared with Mach number of 1.7, Mach number of 2.0 are propitious to the formation of the detonation waves and resulting in a 200mm forward of the position of flame coupled with the shock waves. The initiation time of detonation waves was reduced by more than 1800μs because of the reflector. For the conical reflector, when the blockage ratio was set as 0.403, it can best trigger the detonation.In the experimental study about the cellular structure, the fume-trace method was employed to collect the cellular structure of detonation waves. Results show that the internal detonation wave has complex three-dimensional structure. The generation of transverse wave and formation of hot spots, were influenced by the intensity of shock waves.The conclusions of this paper offers abundant experience for the research of the detonation initiated by PDE. It has some reference value for development of the PDE in the future.