Deflagration to Detonation Transition and Detonation Wave Structure of Aluminum-Air Mixture

Motivated by the current interest in the mechanism of the deflagration to detonation transition (DDT), the DDT process and detonation wave structure of aluminum-air mixture are investigated experimentally by a large scale tube with length of 32.4 m and inner diameter of 0.199 m. The overall DDT process can be divided into slow reaction compression stage, pressure wave speed-up and shock wave formation stage, transfer from shock reaction to critical shock reaction, transfer from critical shock to overdriven detonation, and detonation stage. The optimal concentrations of mixtures in this experimental tube are obtained, and the critical concentration of DDT is also studied. Eight pressure gauges are well-distributed at each periphery of four certain sections in the 1.4 m long detonation testing tube for detonation wave testing. According to the test results, the detonation wave structure of aluminum-air mixture is analyzed, which shows single head mode.