Parametric study of combustion oscillation in a single-side expansion scramjet combustor

As a promising candidate for future air-breathing systems, the viability and efficiency of scramjet propulsion is challenged by a variety of factors including the combustion oscillation in scramjet combustor. A series of comparative experiments focusing on the combustion oscillation issue has been carried out in the present work. The obtained experimental results show that as the global equivalence ratio increases, the combustion oscillation becomes more regular and frequent which is the most intensive in the vicinity of the fuel jet and the periodic combustion oscillation is more possible when the injectors and flame-holding cavity are mounted on the expansion-side wall. In order to avoid the combustion oscillation in scramjet combustor, distributed injection scheme is an effective method which can induce two parts interacting stable flame. In addition, the results reveal that the varying fuel including hydrogen, ethylene and kerosene with different chemical kinetics has a significant effect on the reaction process in scramjet combustor, which can result in stable combustion, periodic oscillation and failed ignition respectively on the same operating condition of this paper. We believe that the present work is helpful to the designing of scramjet propulsion device.