Numerical Investigation of the Effects of Diaphragm Depth on Shock Waves Focusing Detonation

Considering the complex effects of geometric structure parameters on shock waves focusing detonation, a numerical investigation was carried out to study the toroidal shock waves focusing detonation phenomena in this paper. The changing characteristics of shock waves focusing process, flow field evolution features and detonation wave parameters were analyzed in detail by using different diaphragm depths. The results showed that both the local explosion caused by shock waves focusing in cavity and the entrainment vortex formed due to the jet of shock waves or flame in front of diaphragm were very important mechanisms for detonation initiation. And diaphragm depth was a key parameter to affect the deflagration to detonation transition (DDT) performance of toroidal shock waves focusing detonation. With the increase of diaphragm depths, the shock waves focusing strength in cavity could be enhanced. The energy loss backed into circular seam by local explosion was decreased. The interaction between shock wave and flame was improved. All of these leaded that the DDT distance and time were shortened significantly. Besides, when the diaphragm depths were changed from 1 mm to 3 mm, the self-sustaining propagation stability of detonation waves could decrease firstly and then increase. The main reason of this phenomenon was the interaction effects of the strength and triple-point detonation waves. © 2021, Science Press. All right reserved.