Dynamics of a Transversely Excited Swirling, Lifted Flame: Flame Response Modeling and Comparison With Experiments

Abstract

This paper describes measurements and modeling of the response of a swirling, lifted flame to transverse flow excitation. The problem is motivated by combustion instabilities associated with transverse acoustic modes of combustors. The developed formulation relates the unsteady flame response characteristics to both the spatially filtered disturbance field and mean flow field characteristics. Measured flow and flame features are used as model inputs in order to compare the global heat release fluctuations with those measured from the experiment, showing quite good agreement. As such, this paper shows that, given sufficient flow field information, the dynamic flame response can be reasonably predicted from first-principles calculations with no empiricism. We also show that the strongly helical disturbances present in the flow have minimal impact on the global response of axisymmetric flames, as the local heat release fluctuations that they induce cancel each other azimuthally.