Effects of wall velocity slip on droplet generation in microfluidic T-junctions

The effect of the slip lengths of both continuous and dispersed phases on droplet formation in microfluidic T-junctions is investigated by a volume of fluid method. Results reveal that, in a dripping regime, the droplet size is mainly influenced by the slip length of the continuous phase and increases with it. In a squeezing regime, the droplet size decreases with the slip lengths of both phases. The effects of the slip lengths of both phases on droplet generation are systematically discussed and summarized. The elongation rate of the thread can be decreased with an increase of slip lengths in both dripping and squeezing regimes, which is beneficial to improve droplet monodispersity. The monodispersity of droplets can deteriorate when the slip length of either phase is small and can be improved by increasing the slip length of the other phase.