Dynamics of spray - Swirl - acoustics interactions

Combustors with fuel-spray atomizers are particularly susceptible to pressure or velocity oscillations resulting from the occurrence of thermoacoustic oscillations. Experimental investigations of distilled water spray - swirl - acoustic interactions are presented. The presence of a swirl flow field alters the behavior of water spray drastically. Investigations showed complex behavior of water sprays in an acoustic cycle. In the presence of acoustic oscillations the phase averaged droplet diameter variation with in an acoustic cycle is more at the axial locations compared with off axis locations. The phase averaged axial velocity variation of the droplets is high compared to that of phase averaged radial and tangential velocities with in an acoustic cycle. Periodic clustering of droplets in the spray field is observed in the presence of acoustic field. A maximum particle count of 14 times the minimum count in a phase angle bin is observed within an acoustic cycle for the acoustic pressure amplitude of 3000 Pa. The droplet diameter distribution in the spray field is affected in the presence of acoustic oscillations.