Atomization of acoustically levitated droplet exposed to hot gases

Abstract

We, herein, report a fatal instability in an acoustically levitated droplet when exposed to hot product gases of a flame. The initially stable millimeter size droplets were observed to undergo a critical deformation and, subsequently, strong and continuous equatorial atomization, in the form of daughter droplets with a diameter less than 100 μm. Subsequent analysis using a numerical simulation have shown that such thermally induced atomization is caused by dramatic changes in the acoustic pressure around the evaporating droplet due to the presence of a large amount of binary molecules, a critical aspect which was not accounted for in previous analyses of such instabilities.