中心分级燃烧室旋流液雾火焰的外激响应

Centrally-staged combustor can significantly reduce pollutant emissions, but they are susceptible to combustion instabilities. This paper first obtains the self-excited oscillation characteristics of a centrally-staged combustor through experimental methods. Subsequently, large-eddy simulation (LES) is employed to analyze the related flow and flame responses. The results indicate that as the equivalence ratio of the dome increases or the staging ratio decreases, the swirl flame transitions from a stable combustion state to a limit-cycle oscillation state. At low forcing amplitudes, the flow field is dominated by a central vortex tube, which, however, cannot lead to the global heat release rate fluctuation. As the amplitude increases, axisymmetric vortex structures emerge in the flow field, causing significant fluctuations in the heat release rate. Higher forcing amplitudes lead to a decrease in the receptivity of the shear layer to the forcing, leading to a reduction in the gain of the flame response.