Effect of Fuel Injection Allocation on the Combustion Characteristics of a Cavity-Strut Model Scramjet

The cavity-strut supersonic combustion organization method has been found to improve the combustion performance of ethylene in recent studies. In this work, liquid kerosene combustion experiments have been carried out in a model scramjet combustor with a cavity and small strut upstream of the cavity. The effect of fuel injection allocation between the transverse injectors at the strut leading surfaces and duct wall upstream of the cavity on the combustion characteristics has been investigated. In the experiments, a larger bench thrust increment, a higher specific impulse, and an improvement in isolating the interference from the downstream region have been obtained as more of the fuel was injected from the strut injectors. Increasing the strut injection proportion makes the combustion zone translate to the divergent segment downstream of the cavity, and leads to the dominant flow changing from subsonic to supersonic in the minor fuel-rich condition. (C) 2014 American Society of Civil Engineers.