Experimental study of effects of fluidic obstacle parameters on deflagration-to-detonation transition

To investigate the effect of jet in cross flow on the process of Deflagration-to-Detonation Transition(DDT),an single-shot detonation experiment is conducted in a rectangular channel with a height of 20 mm,a depth of 6 mm,and a total length of 810 mm.The premixed methane/oxygen mixture is the reactant,which is ignited by a 50 mJ spark plug.The diameter of the injector of jet in cross flow is 1 mm,and the injection gas is the same concentration premixed mixture.The effect of the jet delay time,the jet location,the quantity and jet distribution pattern on detonation initiation are studied by a series of tests.The results show that there exits at various injection locations the corresponding optimal jet delay time to minimize the DDT time.The DDT time of the parallel double jets located 90 and 270 mm away from the ignition zone and the staggered jets located at 90 and 180 mm away from the ignition zone is the shortest,about 1 ms.