Effects of Entrance Mach Number and Fueling Distribution in a Cavity-Based Scramjet Combustor

The effects of isolator entrance Mach numbers and fueling distributions on combustion characteristics were investigated experimentally in a cavity-based scramjet combustor. The test facility consists of a vitiation heater using methane fuel, nozzles simulating isolator inlet flow, an isolator with constant cross-sectional area, and a combustor with a cavity flameholder. The supersonic combustor has the primary fuel injectors and the secondary fuel injectors upstream and downstream of the cavity, respectively. Combustion experiments were conducted using a gaseous surrogate fuel mixture of 64% ethylene and 36% methane by volume, with isolator entrance Mach numbers of 2.2, 2.4, and 2.6, under the simulated flight conditions of [Formula: see text] and 5.2. From flame visualization, it was observed that as the equivalence ratio increased, the cavity-stabilized and the jet-wake-stabilized combustion modes were identified. According to the isolator entrance Mach numbers and fueling distributions, the wall static pressure measurements and the quasi-one-dimensional analysis results showed the combustor pressure rise, precombustion shock train, and combustion mode transition characteristics. Additionally, the net specific stream thrust and combustion efficiency were derived from Pitot pressure measurements.