Combustion of vaporized kerosene in supersonic model combustors with dislocated dual cavities

Supersonic combustion of vaporized kerosene in a Mach 2.5 model combustor with a total temperature of 1500 K and a total pressure of 1.3 MPa was experimentally investigated for an optimal integration of the cavity-based flameholder and the fuel injection scheme. Anovel design of a supersonic model combustor consistingof atwo-staged fuel injection system and dislocated dual cavities was proposed to improve the combustor performance, including the combustion efficiency, flame stabilization, combustor "unstart," and heat release distribution. Specifically, a large number of experiments were performed to systematically investigate the effects of fuel injection distribution, which is controlled by varying the injector spacing and the fuel equivalence ratio, on the static pressure distribution, thrust increment, lean blowoutlimit, wall temperature distribution, and combustor unstart characteristics. The results show that there exists an optimal range of injector spacing to obtain enhanced combustion performance while avoiding the combustion unstart. Furthermore, the equal fuel injection withan overall equivalence ratio of 0.5 for the two injectors was found to result in the optimal static pressure distribution and hence the largest thrust increment.