Experimental study on the propagation characteristics of rotating detonation waves in the plane-radial structure

In order to study the propagating characteristics of rotating detonation waves in the plane-radial structure, experiments were carried out in a plane-radial rotating detonation engine (RDE) with a variable reactants mass flow rate and equivalence ratio. Results indicate that detonation waves initiate successfully and propagate continuously on the plane-radial RDE, leading to two kinds of propagation modes:single-wave and two-wave propagation mode. The interaction between the plenum chamber and the combustor occurs in the operating process. When the mass flow rate is less than 159.20 g/s, rotating detonation waves propagate in the single-wave mode. The propagation frequency varies from 4.56 kHz to 4.62 kHz. The pressure peak and the velocity of detonation waves increase with the decreasing distance from the outer circle. In the case of the mass flow rate larger than 186.89 g/s, detonation waves propagate in the two-wave mode and the frequency varies from 8.59 kHz to 8.64 kHz. The two-wave propagation mode undergoes four stages:the single-wave stage at the initiation, the stable two-wave stage, the unstable two-wave stage, and finally the single-wave propagation stage in the exhausting stage. When the mass flow rate varies from 159.20 g/s to 186.89 g/s, rotating detonation waves propagate in the single/two-wave mixed mode. When the equivalence ratio is close to the stoichiometric ratio, the propagation process of detonation waves is more stable. In contrast, the detonation wave propagation is unstable and there is a failing initiation at the beginning or an interruption in the propagation process when the equivalence ratio is deviated from the stoichiometric ratio.