Blowout Limits of Cavity-Stabilized Flame of Supercritical Kerosene in Supersonic Combustors

Abstract

Blowout limits of cavity-stabilized flame of supercritical kerosene were experimentally studied by using Mach 2.5 and 3.0 direct-connect supersonic model combustors operated under various air and fuel conditions. Specifically, the effects of the stagnation temperature and the stagnation pressure on the blowout limits were investigated for supercritical kerosene injected from the wall upstream of a cavity flameholder in a Mach 2.5 combustor. Experiments were performed under the same conditions for supercritical kerosene injected from the rear part of the cavity bottom to study the influence of the location of fuel injection. The blowout limits of supercritical kerosene injected from the wall upstream of the cavity were further investigated in a Mach 3.0 combustor. Besides the effects of the stagnation temperature and stagnation pressure, the effect of the divergence angle of the combustor on the lean-fuel blowout limit was studied. Results show that there exist two blowout limits corresponding to the lean- and rich-fuel conditions for a given stagnation temperature. The location of fuel injection has substantial influence on the blowout limits, whereas the influence of the stagnation pressure and the divergence angle of the combustor can be neglected in the range of interest.