Characterization of wave modes in a kerosene-fueled rotating detonation combustor with varied injection area ratios

Abstract

The rotating detonation engine (RDE) is an innovative and practical pressure-gain device for rocket and ramjet propulsion, and has been widely investigated. The present work aims to explore at length the characteristics of two-phase rotating detonation waves in a typical RDE, particularly characterizing the effects of the injection area and equivalence ratios on the propagation modes. Series of experimental tests were carried out in the specifically designed rotating detonation combustor propelled by liquid kerosene and oxygen-rich air, where the high-speed imaging technique was adopted for visually capturing the traveling trajectories of the detonation waves. The experimental results demonstrated that the rotating detonation wave always propagated in a hybrid mode of single-wave and dual-wave collision. In the single-wave mode, traces of local combustion in the combustor were clearly observed. While for the dual-wave collision mode, the luminosity denoting the reaction intensity was much weaker, and positions of the collision point shifted frequently. The spontaneous mode transitions in the combustor were presented through the synchronous detection of the high-speed camera and pressure sensors, which are the typical characteristics of the hybrid wave mode. The results also implied that a reduction in the injection area increased the pressure of the RDC and the velocity of the detonation waves, and was likely to suppress the deflagration mode. Such a decrease in the injection area ratio finally increased the occurrence time of the dual-wave collision mode during the operation of RDE. The findings could serve as a reference for the design of the propellant injection structure of liquid-fueled RDE.