This paper presents an analysis of the response of a flame to acoustic excitation, by means of a heat release rate measurement technique based on flame chemiluminescence emission. A kerosene/air two-phase flame, produced downstream from an industrial aeronautical injector, is acoustically excited using a siren located upstream from the injector. The influence of the frequency and amplitude of the imposed excitation is analyzed using the flame describing function. For low levels of excitation imposed by the siren, the flame response depends linearly on the amplitude and frequency of the excitation. The influence of frequency is linked to the longitudinal acoustic modes of the test bench. Above a certain excitation level, a saturation effect is observed. Phase analysis of the flame describing function shows that the flame initially becomes more compact and moves closer to the injector. For higher excitation amplitudes, a coupling phenomenon characterized by an in-phase oscillation of the acoustic pressure measured in the combustion chamber and the heat release rate emitted by the flame is observed.
Desclaux et al. (Tue,) studied this question.