Abstract
The feasibility of mode control in rotating detonation engine is investigated through regulating the global equivalence ratio during the test under different air mass flow rates, chamber lengths, and blockage ratios at the exit, including the mode transitions between the single wave and two co-rotating waves, two counter-rotating waves and longitudinal pulsed detonation, two co-rotating waves and longitudinal pulsed detonation. The rotating detonation wave propagating in the mixture with fuel concentration gradients under single wave mode is also tested. The results show that, the rotating detonation wave has the ability to adapt itself to the changing of equivalence ratio. The decreasing of the equivalence ratio leads to the poor reactivity of mixtures, which decreases the wave speed under the single wave mode, and results in the transition from two co-rotating waves to single wave. The increasing of the chamber length decreases the critical equivalence ratio for the emergence of longitudinal pulsed detonation. Increasing the chamber length leads to the transition from two counter-rotating waves to longitudinal pulsed detonation at relatively low equivalence ratio. This paper demonstrates the feasibility of mode control in rotating detonation engine, and promotes the application of rotating detonation engine.