Experimental investigation on the propagation mode of rotating detonation wave in plane-radial combustor

Abstract

A plane-radial rotating detonation engine (RDE) was tested to identify the impact of different injection conditions on the propagation mode and parameters of rotating detonation wave (RDW). Changing the mass flow rate and equivalence ratio, various propagation modes were obtained in experiments: one-wave mode, two-wave mode, three-wave mode and unstable propagation mode. The operating ranges of various propagation modes were acquired. Results indicate that, in this structure, under the condition of stoichiometric ratio, when mass flow rate is less than 122 g/s, the RDE operates in unstable mode, and the RDW propagation velocity is less than 1500 m/s at Ф102 mm. Low frequency oscillation occurs in unstable mode, and the oscillation frequency is approximately 300 Hz. When mass flow rate is greater than 122 g/s, with the increase of mass flow rate, the propagating mode is transformed from one-wave mode to two-wave mode, and then changes into three-wave mode. The propagation velocity in one-wave mode is higher than that in other modes, and varies from 1785 to 1900 m/s. The velocities in two-wave and three-wave mode have little difference, and vary from 1547 m/s to 1650 m/s in two-wave mode, and from 1525 m/s to 1578 m/s in three-wave mode. The mass flow rate has only a slight effect on the RDW propagation velocity, but a large effect on the pressure peak under the same mode. Furthermore, the variation of equivalence ratio will alter the propagation mode, and the RDE operating range of equivalence ratio widens as the mass flow rate increases.