Shock-Flame Interaction and Deflagration-to-Detonation Transition in Hydrogen/Oxygen Mixtures
The interaction of shock waves with the flame fronts is an important mechanism leading to flame acceleration, transition from deflagration to detonation (DDT), transition to turbulence. It results in distortion of the flame, the increase in the energy release rate, can lead to considerable flame acceleration and DDT and it is of great practical interest in the context of safety problem. There have been numerous of previous attempts to simulate the shock-flame interaction numerically using a simplified chemical model of a one-step exothermic reaction (see  for recent review). However, a one-step reaction model cannot reproduce the main properties of the combustible mixture such as induction time in chain-branching kinetics. Taking into account considerable difference in the induction times obtained from detailed chemical models and from one-step models, the results of simulation using a onestep model must be considered with greatest discretion. It was shown  that the evolution to detonation from the temperature gradient is profoundly different for detailed chain branching kinetic models than for one-step kinetic models and that the steepest temperature gradient capable to initiate detonation is by orders of magnitude more shallower compared to that predicted from a one-step model for highly reactive mixture (H2/O2) and even more for slow reactive mixtures (methane/air). Use of reliable detailed chemical kinetic models is important for correct understanding of combustion phenomena since results obtained using chain-branching chemistry models are considerably different from that found for one-step chemistry. It is therefore important to investigate and understand the differences in the shock-flame interaction between chain-branching kinetics and previously obtained from one-step models.
In this work we report selected results of high resolution two-dimensional numerical simulations with a detailed chemical kinetics of the series of comprehensive study of the interaction of a flame with an incident shock and then with a shock reflected from the endwall. The flame distortion by the shocks, the increase of the energy release rate in the system, and the transition from deflagration to detonation (DDT) caused by the shock-flame interaction are investigated.
KeywordsEnergy Release Rate Induction Time Incident Shock Incident Shock Wave Combustible Mixture
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