Experimental research into the characteristics of child droplets formed due to collisions of liquid fragments in a gas

We show the ranges of droplet size reduction depending on the relative velocity before interaction, initial dimensions of each of the droplets and their ratio, as well as the Weber, Ohnesorge, Reynolds, and capillary numbers. Experiments are conducted for water, Diesel fuel emulsion, and castor oil emulsion. The ranges of a prospective increase in the liquid surface area due to droplet collisions as a function of the variable parameters are determined. We single out three Weber variation intervals: <50 (drastic change in the number of child droplets), 50–150 (lower increment rate of the number of child droplets), >150 (the number and dimensions of child droplets remain the same with an increase in the Weber number). The number and average size of child droplets are influenced by the relative velocity of the two parent drops, the ratio of their dimensions, as well as the angular and linear collision parameters.