Experimental Study on the Generating Condition of Over-Detonation during the Gaseous DDT

To verify the three current international views on the generating condition of over-detonation during gaseous deflagration-to-detonation transition (DDT), the DDT process of gaseous hydrogen-oxygen mixture was experimentally studied by using pressure sensors. The whole pressure histories of gaseous DDT from detonation to DDT and then to stable detonation were obtained. The experimental results showed that the generation of DDT requires certain physico-chemical conditions, and for certain initial pressure conditions, the transformation time (or distance) decreases firstly and then increases with increasing concentration of hydrogen. The peak pressure in over-detonation is about 1.5~2 times as much as that in the stable detonation.