Characteristics of thermoacoustic resonance in a ducted burner

Abstract

Combustion instability accompanied with low-frequency oscillations is one of the typical phenomena in a ducted flame burner. This is due to the interaction between unsteady heat release and the sound pressure field known as thermoacoustic feedback. A parametric study was carried out through measurements of acoustic pressure and flame radiation at various conditions not only to elucidate the effect of Reynolds number and equivalence ratio on thermoacoustic oscillation, but also to understand the mechanism of the onset of thermoacoustic resonance in a ducted flame burner. The results explain that equivalence ratio has significant effects on the magnitude of pressure and heat fluctuation as well as the fundamental frequency. It is also found that the onset of thermoacoustic resonance is strongly affected by the interacting mechanism between acoustic energy and heat release.