An Analysis of the Droplet Splitting Ratio in Asymmetric T-junction

There is an increasing interest in splitting droplets into two smaller, unequal, droplets as a major functional feature in a variety of microfluidic applications. In this work, the dynamics of droplet breakups in an asymmetric microchannel T-junctions system is investigated. Finite volume simulations were conducted in ANSYS Fluent for the splitting of water micro-droplet in oil within an asymmetric T-junction to examine the breakup dynamics. The evolution of droplets during breakup was examined. The splitting ratio for asymmetric breakup is presented under different flow conditions. In particular, the focus is with the breakup with permanent obstruction and the unstable breakup regimes. More often, the splitting ratio is often larger than the pressure gradient ratio and only in certain circumstances it is equal to the pressure gradient ratio. The splitting ratio may increase to up to twice of the pressure gradient ratio of the T-junction as Capillary number decreases for breakup in the unstable breakup regime. For the case of the splitting ratio follows the pressure gradient ratio, breakup is in the permanent obstruction regime. Additional factors affecting the breakup process such as the cross-section area and the interfacial properties are also examined.