Asymmetric breakup of a single droplet through a Y-junction microchannel with non-uniform flow rate

In this paper, the asymmetric breakup dynamics of a solitary water droplet through a Y-junction microchannel with a non-uniform outlet flow rate is numerically investigated under a spacious range of capillary number (0.01 < Ca < 0.3), outlet flow rate ratio (1 < k < 11), and initial droplet volume (0.7 < V* < 4.0). Four distinct breakup patterns, namely, Obstructed-Obstructed breakup, Obstructed-Tunnel breakup, Tunnel-Tunnel breakup, and Non-breakup, are recognized. The quantitative impacts of the significant parameters on the breakup characteristics are determined, and the breakup threshold is predicted using the correlations. As per the results, the evolution of neck thickness is significantly influenced by the outlet flow rate ratio and capillary number but is less dependent on the initial droplet volume. A series of functional correlations are proposed under various Ca and V* values to describe the variation in the splitting ratio of offspring droplets based on the exponential law.