Experimental Visualization of the Structure of Rotating Detonation Waves in a Disk-Shaped Combustor

The rotating detonation engine is a propulsion system that obtains thrust using continuously existing detonation waves. A rotating detonation combustor usually has an annular shape that allows detonation waves to propagate in the circumferential direction. In this study, we used a disk-shaped rotating detonation combustor with a combustion chamber with flat-plane glass walls to observe the structure of the phenomena. Self-luminescence, shadowgraphs, and schlieren visualization experiments were performed and compared. Results revealed that detonation waves were propagating in a mixture layer of three gases, fuel, oxidizer, and burned gas at 1600 to 900  m/s; Chapman-Jouguet velocity was 2376  m/s. Waves maintained a three-dimensional complicated wave shape in the disk-shaped combustion chamber with parallel-jet injectors.