Experimental Study of a Cylindrical Rotating Detonation Combustor for Scramjet Ignition

A cylindrical rotating detonation combustor used as a torch igniter (RD torch) was investigated to achieve ignition and flameholding under flight Mach 3–4 conditions. Supersonic experiments were conducted at a direct-connected supersonic combustion wind tunnel facility. Gaseous ethylene/oxygen and hydrogen were employed as the torch fuel/oxidizer and the main fuel, respectively. The RD torch operated at [Formula: see text] with an equivalence ratio of [Formula: see text] in a 10-mm-diameter chamber. The scramjet model combustor was tested with main [Formula: see text] of [Formula: see text] and [Formula: see text] and an air supply of [Formula: see text] at a total temperature of [Formula: see text] and a Mach number of 2.8. As a result, torch exhaust was continuously injected into the cavity, and combustion was nearly completed within the torch. A detonation wave propagated at 2.07–2.14 km/s, corresponding to 85–88% of the Chapman–Jouguet detonation velocity and 158–163% of the sonic velocity in the burned gas. Ignition and flameholding of the main [Formula: see text] and supersonic combustion were achieved with the RD torch. The results also highlight three characteristics: short combustion region, resilience to external disturbances, and circumferential exhaust momentum.