Two-phase flow and morphology of the gas-liquid interface for bubbles or droplets in different microchannels

Two-phase interface fluid, bubble or droplet, has shown broad application potential in oil and gas field development, contaminated soil remediation, and medical treatment. These applications are particularly concerned about the flow characteristics of the two-phase fluid in different channels. Herein, we summarize and analyze the research progress in the flow of bubbles (or droplets) in different channels, mainly including simple, Y-junction/T-junction, and obstructed microchannels. At present, there is no systematic theory about the structure and mechanical evolution of the two-phase interface fluid, and therefore, the comprehensive study is still insufficient. Especially, current studies on the breakup of the two-phase interface in bifurcated channels mainly focus on a few of specific perspectives and a general conclusion is not achieved. In addition, to systematically verify the mechanism of bubble (or droplet) breakup, extensive studies on the three-dimensional physical model of bubbles (or droplets) are needed. Furthermore, we have also sorted out the involved influencing factors, as well as the prediction models for bubble (or droplet) breakup and retention in different channels, and in the end, we provide suggestions for the potential research and development of the two-phase interface fluid.