Study on the combustion characteristics of high-speed non-premixed reactants enhanced by rotating detonation jet

Abstract

The afterburner is indispensable for the short-term power enhancement of military engines. In order to achieve stable and efficient combustion in the afterburner and reduce the weight of the combustion chamber, it is very important to explore an efficient combustion organization scheme. Rotating detonation engine is an engine that uses continuous rotating propagation of detonation waves in the combustion chamber to generate a stable thrust and detonation waves can propagate continuously and stably with only one-time ignition. In this study, the in-line injection mode of the injector in the afterburner is taken as the research background, and the scheme of using rotating detonation jet to enhance the mixing and combustion process of fuel cross-flow and high subsonic parallel flow is proposed for the first time. The results show that the rotating detonation jet combustion enhancement scheme is a promising method to achieve efficient combustion of high-speed non-premixed reactants. As far as the current simulated working conditions are concerned, the maximum combustion efficiency of this method can reach 89.93 %. In addition, there is a suitable rotating detonation combustor size and connected domain distance to achieve the best combustion enhancement effect. Improper geometric parameters will affect the baroclinic torque structure, the strength and continuity of the vortex distribution, and the continuity and area of the flame stability zone, thus affecting the combustion enhancement effect. Three main mechanisms for the enhancement of non-premixed combustion by periodic rotating detonation jet are summarized. Combined with the analysis of cases with different connected domain distance, it is found that the formation of specific baroclinic torque structure and the interaction between shock wave and flame are the dominant mechanisms.