Abstract:
Due to high energy release rate, the applications of detonation in propulsion syste ms have aroused strong interest. There are two important phenomena related with detonation:detonation initiation and propagation. Categorically, a detonation wave can be initiated either directly, through a rapid deposition of energy, or indirectly. In direct detonation initiation, there are higher energy. Indirect detonation initiation is always research hotspots, in which deflagration-to-detonation transition (DDT) is the focus. After decades of experimental, theoretical and numerical research, the DDT mechanis ms have been understood. However, it is unable to achieve accurate prediction, in which the main challenge is turbulent combustion. According to detonation propagation, especially for the combustible mixture with high activation energy, there are the turbulent nature of the reaction zone in detonation wave structure and the presence of unburnt gas pockets that are convected downstream into the wake of the detonation front. This behavior makes the accurate control of detonation wave difficult. But, the average velocity of detonation can be predicted by the CJ theory velocity. In this paper, the recent developments in the DDT and detonation wave structure are reviewed, and the future research is prospected.