Swirl Flame Response to Simultaneous Axial and Transverse Velocity Fluctuations

Abstract

In this experimental study, we investigate the impact of transverse acoustic velocity fluctuations on flame response to axial velocity fluctuations. Such a scenario where a flame is under the influence of a 2D acoustic field occurs in annular gas turbine combustors during thermoacoustic instability. A generic premixed swirl flame is exposed to simultaneous transverse and axial acoustic forcing. The amplitude of axial forcing was kept constant, while the amplitude and relative phase (with respect to axial forcing) of the transverse forcing was systematically varied. Results obtained indicate that transverse velocity affects flame response, and that both the magnitude of transverse velocity and its phase with respect to axial forcing are important factors.