Experimental investigation of the unsteady response of premixed flame fronts to acoustic pressure waves

Athéna Wangher (1) , Geoffrey Searby (1) , Joel Quinard (1)

1 IRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre

Using OH chemiluminescence, we measure the experimental unsteady response of a 1–D premixed flame to an acoustic pressure wave for a range of frequencies below and above the inverse of the flame transit time. We find that the response is positive and, at low frequency the order of magnitude is comparable with existing theoretical analyses. However, if it is supposed that the chemiluminescence is proportional to the mass consumption rate, despite some uncertainty in the interpretation of the chemiluminescence signal we find that the frequency dependence of the measured response is not compatible with the predictions of the standard flame model for one-step Arrhenius kinetics. A better, but not perfect, correlation is obtained for the heat release rate. We conclude that the standard model does not provide an adequate description of the unsteady response of real flames, and that it is necessary to investigate more realistic chemical models.

Mots clés: Acoustic-flame interaction; Combustion instabilities; Instantaneous reaction rate; Chemiluminescence

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Athéna Wangher, Geoffrey Searby, Joel Quinard. Experimental investigation of the unsteady response of premixed flame fronts to acoustic pressure waves. Combustion and Flame, 2008, 154, pp.310-318. ⟨10.1016/j.combustflame.2008.03.002⟩. ⟨hal-00275360⟩