On the droplet formation process in an X-shaped microfluidic device

The paper describes the results of an experimental study of the generation of microemulsions in a microfluidic device of own production equipped with an X-shaped mixer. The presented pattern diagrams showed a significant effect of the surfactant concentration on the flow regime in the channel and on the size of droplets formed. A universal equation is obtained for calculating critical capillary numbers that determine the transition between flow regimes. A preliminary analysis of force factors affecting the process of formation of droplets in a dispersion phase is carried out. It is revealed that the tangential stresses in the gap between the channel wall and the droplet, the pressure gradient along the droplet, and the interfacial tension forces have one order of magnitude and to a greater extent determine size of formed droplets. On the basis of force analysis, the diameter of droplets formed the under specified conditions was calculated, and calculation maps of flow regimes qualitatively confirming the data of the experimental study were developed.