Droplet generation and breakup in a ribbed microfluidic T-junction for scalable emulsification process

The present work reports a numerical investigation of droplet formation and breakup in a specially designed ribbed microfluidic T-junction. The ribbed microfluidic T-junction is proposed to enhance the operating conditions of droplet formation and splitting operations required in the emulsification process. Two sets of ribs are incorporated in the microfluidic T-junction to help the droplet formation at a low flow rate and to convert the unconfined droplet to a confined droplet for its further splitting in a sequential T-junction. The effects of different parameters on the confinement and the breakup mechanism for an unconfined droplet through the ribbed channel are studied. Transient deformation of an unconfined droplet, as it moves through the ribbed channel and consequent change in inertia and surface tension force help the confinement of the droplet. Confinement is required for a droplet with high viscosity for its breakup in the splitting channel. However, an unconfined droplet is broken in the splitting channel at a very low viscosity. Droplet breakup time decreases during the splitting with permanent obstruction. Vorticity along the droplet’s tip decreases with an increase in the flow rate ratio. The modified ribbed T-junction broadens the range of droplet splitting, i.e., at low flow rate ratios and high Capillary numbers required for various droplet-based microfluidic applications.