Coalescence and Separation of Monodisperse Droplets

Abstract

The liquid ejected from a small hole will break out under the action of the surface tension. If an excitation is applied with a certain frequency, the jet will disintegrate into droplets, and the droplets flowing with uniform particle size and space will be obtained, which can be used for study of droplet dynamics. In the process of developing a droplet generator, it is found that the different methods of liquid supply have significant effects on the droplet flow quality. The droplet flow will catch up to coalesce or separate. By using the dimensionless parameters Reynolds number, Weber number, Bond number and Ohnesorge number to analyze the process of the droplet flow, the drag coefficient Cd of the droplet in the process of catching up is obtained. The role of inertial force, surface tension and viscosity effect in the process of droplet coalescence and separation is described, and the device is improved to prohibit this phenomenon happening.