Experimental study on suppressing pressure feedback and combustion product backflow of the rotating detonation engine

Abstract

To further improve the feedback suppression effect of rotating detonation engines (RDEs), an optimized Tesla valve inlet structure (TVI-II) was designed on the basis of the previous research of our research group. Taking kerosene and 29% oxygen-enriched air as the reactants, the operation characteristics, the feedback suppression effect, and the feedback suppression mechanism were obtained through a series of experiments. It is found that due to the existence of bypass channel, TVI-RDE can effectively suppress the occurrence of longitudinal pulsed detonation and broaden the working boundary of the engine. The working range of the TVI-I-RDE was broadened by 183.3%, and that of the TVI-II-RDE was broadened by 700%. The TVI-II-RDE is more effective in suppressing pressure feedback and combustion product backflow. When the pressure feedback phenomenon occurs, the rotating detonation wave mainly decoupled and attenuated in the converging section of bypass channel. The minimum pressure feedback percentage (PFdw) of TVI-II-RDE was 11.4%, as compared to about 40% for the TVI-I-RDE. The change law of the air plenum pressure fluctuation percentage (PFap) was similar to that of PFdw, and the minimum PFap of the TVI-II-RDE was about 7.7%. Narrower bypass channel width would lead to longer residence time of combustion products. The effective inlet area ratio (EA) of the TVI-II-RDE was at least 95.7%, which is at least 6.1% higher than that of the CDI structure. The results show that the TVI-II-RDE has great potential in suppressing feedback, which promotes the engineering application of RDE.