Characterization of droplet bag-stamen breakup under shear effect

Abstract

We conducted an experimental study of droplet breakup under shear effect at different We_g and We_d conditions, and observed and measured the morphology of droplet bag-stamen breakup which represents a case where bag and stamen structures occur simultaneously during droplet fragmentation under shear effect, the deformation pattern, and the size distribution of its sub-droplets by the continuous jet method. Through the observation of the morphology, two bag-stamen breakup variants with different manifestations under shear effect were named; the empirical formulas for predicting the deformation of droplets affected by We_g in shear flow were summarized; the sub-droplet size distributions of droplets after breakup in shear flow were statistically analyzed, and the size distributions of the fragment at We_d = 20 basically conformed to the log-normal unimodal fit, and with the increase of We_g, the single peak size distribution of the fragment was found to be very similar to the single peak fit of We_g. With the increase of We_g, the single-peak structure showed a tendency of weakening and then strengthening, and at the same time, the single-peak position moved to the direction of increasing sub-droplet size.