关键词: 狭缝管；传播模式；速度震荡；速度亏损；过驱爆轰

Abstract: To study initiation and propagation characteristic of detonation in a narrow gap，the gaseous detonation of stoichiometric ethylene/oxygen mixtures through a 1.0mm-height and 20mm-width narrow gap was experimentally studied with different initial pressure (p0=10～60kPa). The soot film was utilized to record the cellular structure of detonation，and the high-speed cinematography was used to capture the flame. The results show that，by decreasing the initial pressure of a given mixture，four modes of propagation could be clearly identified: stable detonation mode，‘stuttering’detonation mode，galloping detonation mode，and low-velocity stable mode. For unsteady detonation，such as‘stuttering’detonation mode and galloping detonation mode，the velocities had high fluctuation and cellular structure of overdriven detonation periodically appeared in soot film. During the next stage，the‘stuttering’detonation wave moved between the lateral walls of the rectangular channel with a sigle head mode，while galloping detonation transiently failed. For low-velocity stable mode，the average velocity was about 45% C-J value and no cellular structure appeared in soot film. The value of velocity deficits of detonation propagation appeared in narrow gap is 10%～15%，which is higher than the value of velocity deficits in large size tubes.

Key words: Narrow tube；Propagation modes；Velocity fluctuation；Detonation deficits；Overdriven detonation