Characterization of detonation re-initiation mode in a flat channel with a pre-detonator using chemiluminescence imaging at 200 kHz

The use of a pre-detonator connected to a main chamber is demonstrated to provide reliable and fast detonation to the denotation engines (i.e., pulse detonation engines or rotating detonation engines). One key issue is that the overdriven detonation (OD) occurred in the pre-detonator significantly affects the denotation re-initiation mode in the main chamber. To address this issue, this work reports an experimental study to characterize the detonation re-initiation mode in a flat channel with different OD conditions in the pre-detonator. For this purpose, detonation was first triggered in a smooth pre-detonator and then propagated into the following channel to ignite the downstream mixtures. The chemiluminescence signals generated in both the pre-detonator and the main chamber were captured by the high-speed camera operated at 200 kHz, which is sufficient to capture the detailed dynamic transitions and the wave structures. The results showed that the probability of a fast denotation re-initiation in the chamber increases as the distance between the OD occurring location and the pre-detonator’s outlet decreases. Based on the results, this work suggests a critical condition for the fast detonation re-initiation, which is expected to provide significant guidance to the design of the denotation engines.