Kinetic Effect of Ozone Addition on Deflagration to Detonation Transition of C₂H₂/O₂ Mixtures in Microchannels

The kinetic acceleration of deflagration to detonation transition (DDT) of acetylene/O₂ mixtures at lean conditions in a 1 mm square microchannel is investigated using ozone addition. Equivalence ratios and ozone concentration were varied to understand the thermal and kinetic impacts, respectively, on DDT transition. The addition of ozone was found to drastically reduce the DDT time and onset distance via kinetic enhancement. The results showed that with a small amount of ozone addition, the DDT time was reduced by up to 77.5%, while only slightly increasing CJ velocities, by 6.7%. Moreover, the addition of 1% ozone extended the DDT limit from equivalence ratio of 0.3 to 0.2. Furthermore, it was observed that ozone addition had a much larger effect on DDT time than the increase of equivalence ratio. The present results suggested that for accelerating DDT, the kinetic effect via ozone addition is much greater than the thermal effect.