Deflagration-to-Detonation Transition Induced by Hot Jets in a Supersonic Premixed Airstream

Detonation is initiated through a hot jet in a supersonic premixed mixture of H₂ and air, which is produced by using a air heater. The results show that initiation fails in the low-equivalence-ratio premixed gas. With the increase of equivalence ratio, the hot jet can induce deflagration to detonation transition (DDT) in the premixed mixture, which an indirect initiation of detonation. Further studies show that the DDT process is due to the combined effect of a local hemispherical explosion shock wave, the bow shock, and the flame produced by the hot jet.