Experimental study on rotating detonation wave discontinuous propagation process of high-temperature ethylene-rich gas

The combination of air turbine rocket (ATR) and rotating detonation engine (RDE) is a promising form of combined power, and it is of great significance to study the propagation characteristics of rotating detonation waves (RDW) using rich combustion gas as fuel. Owing to the complex composition of the rich combustion gas, RDWs are prone to unstable propagation. In this study, the discontinuous propagation state of quenching and re-initiation of an ethylene-rich gas RDW was experimentally investigated. It was found that the back pressure of RDWs blocked the air injection process and influenced the mixing effect and filling height of the propellant, resulting in decoupling of the RDW. An increase in the gas temperature would shorten the formation time of the RDW and avoid its discontinuous propagation state. The re-initiation process was similar to the auto-initiation process which the combustible mixture generated an RDW through a deflagration-to-detonation process (DDT). The designed experiment verified this analysis. Increasing the air injection pressure and gas temperature can improve the propagation stability of the RDW and reduce the frequency of the quenching and re-initiation process.