Zheng-Chen-Abstract – ASPACC 2021 Conference

Flame Initiation and Detonation Development in a Gaseous Premixture

Abstract:
Understanding the initiation of premixed flame and detonation is important not only for fundamental combustion research but also for developing advanced combustion engines and controlling of fire and accidental explosions. A premixed flame can be initiated when sufficient amount of external energy is locally deposited into a combustible mixture. Under engine-relevant conditions with high temperature and pressure, the ignition delay time of the unburned gas might be comparable to the characteristic flame time; and thereby strong flame/autoignition interaction occurs which might induce detonation development. In this talk, I will discuss the recent progress on flame initiation and detonation development in a gaseous flammable mixture. First, I will present the recent investigations on ignition kernel development, critical ignition radius and minimum ignition energy. I will discuss the effects of different factors including dilution, fuel stratification and turbulent transport on ignition of premixed flames. In the second part, I will present results on end-gas autoignition, flame/autoignition interaction, and detonation development under engine-relevant conditions. The end-gas autoignition and detonation development are respectively related to normal knock and super-knock in downsized and boosted spark ignition engines. Finally, I will briefly introduce the recent progress on detonation initiation and propagation in non-uniform mixtures, which might occur in rotating detonation engines.

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