Experimental investigation of ignition-detonation time in two-phase valveless pulse detonation engines

This paper focused on investigating the ignition and detonation-initiation performance of avgas-air two-phase valveless pulse detonation engines (PDEs) with inner diameters of 50mm and 120mm in different operation cases. To quantify the ignition and detonation-initiation performance, parameter ignition-detonation time was examined, which was defined as the sum of the ignition time and deflagration-to-detonation transition (DDT) time. In order to observe the effects of ignition energy, operation frequency of PDE and inner diameter of PDE on ignition-detonation time and PDE performance the proof-of-principle experiments of PDEs were carried out. The results indicated that the ignition energy, operation frequency and PDE diameter had important effects on ignition-detonation time. As the ignition energy increased, the ignition-detonation time decreased and the average thrust of PDE increased. As the operation frequency increased, the ignition and detonation-initiation time decreased and the ignition energy effect on ignition-detonation time degenerated. And the ignition-detonation time increased with the PDE diameter increasing. Each of the ignition-detonation times of avgas-air based on pulse detonation rocket engine (PDRE) was lower than that of air-breathing PDE at the same operation frequency slightly.