Characteristics of the travelling speed of droplet flow splitting in bifurcated minichannel networks

The splitting modes of droplet flow in bifurcated minichannel networks is valuable in terms of distributing them in various microfluidics chemical applications and have been widely studied. Previously, the prediction of the splitting modes relies on the models of hydraulic flow resistance. This paper presents an experimental study focusing on the correlation between the droplet splitting modes and the features of travelling speed of droplets at various minichannel networks. A high-speed camera and machine vision algorithm are used to measure the instantaneous travelling speed of droplets at the inlet and the arms of the networks. Five typical splitting modes are identified including bypass splitting, breakup splitting, random splitting, uniform splitting and oscillating splitting. The characteristics of the droplet speed corresponding to different splitting modes are studied and understood by analyzing the varying features and the correlations of them. It shows that the splitting mode can be correlated to the characteristics of the travelling speed of droplets. The research introduces a non-intrusive method to identify and monitor the droplet splitting mode at T-junctions, which only relies on local vision features of several droplets.