Effect of acoustic velocity on the primary atomization of a hollow cone spray in a swirling flow field

Abstract

This paper reports an experimental investigation on the effect of imposed acoustic velocity fluctuations on the primary atomization of a hollow cone liquid sheet in the presence of strong air swirl. The atomization dynamics is elucidated by positioning the spray at an acoustic velocity node, antinode, and a mixed point in the standing wave field generated due to the imposed axial acoustic excitation. High speed shadowgraphy images acquired in-sync with dynamic pressure measurements are processed to extract breakup length, spatial growth rates etc. A novel method to obtain the breakup length of a hollow cone spray from the position of maximum wave amplitude is presented. The phase difference between the left and right half-angle fluctuations shows that the flapping motion of the spray is predominantly observed at the mixed point for different air to liquid ratios.