Formation mechanism and criterion of tail satellite droplets for moving droplet in microchannel

In many applications of microdroplets, the high monodispersity of the product is usually an essential requirement, the appearance of undesired satellite droplets needs to be avoided. In this study, the deformation of droplets and the formation of tail satellite droplets in microchannel were investigated experimentally, and the process mechanism was also explored. Three flow regimes of moving droplets were observed: (1) droplet with convex cap; (2) droplet with tip; (3) droplet with satellite. It was found that the rear cap of the droplet was more prone to deformation. The shearing force on the droplet becomes strengthened with the increase of the superficial velocity of the droplet, the flow rate ratio of two phases or the viscosity of the continuous phase, which facilitates the formation of tail satellite droplets. The critical criterion for formation of tail satellite droplets was proposed, which is at good agreement with the experiment result. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study experimentally investigated the deformation of droplets and the formation of tail satellite droplets in microchannels, revealing that the rear cap of the droplet is more prone to deformation. The critical criterion for the formation of tail satellite droplets was proposed, showing good agreement with the experimental results.