The Effect of Ozone Kinetic Enhancement on Detonation Transition in a Microchannel with Dimethyl Ether Mixture

This study aims to investigate the impact of ozone addition for kinetic enhancement on the Deflagration to Detonation Transition (DDT) and the ignition-shock coupling in a microchannel with dimethyl ether (DME). High-speed chemiluminescence and shadowgraph imaging are employed to examine flame front propagation, shock wave structures, autoignition, and ignition-shock coupling during the DDT process. The experimental findings indicate that autoignition always occurs within the reactivity gradient oblique shock cluster region between the flame front and the precursor shock, and the observed DDT follows the Zeldovich hot spot gradient mechanism. Although the overall steps of DDT are the same for both cases, without and with ozone, the autoignition location, oblique shock strength, induction zone length, and ignition-shock coupling are very different. Without ozone, DDT takes place through ignition wave coupling with the precursor shock, while the ozone addition accelerates autoignition and initiates direct ignition-induced shock coupling without any interaction with the precursor shock. These results show the effective role of kinetic enhancement in autoignition through the use of an ignition enhancer such as ozone or plasma in accelerating and controlling the DDT process.