Experimental and Numerical Studies on Microbubble Generation and Flow Behavior in a Microchannel with Double Flow Junctions

Abstract

Experimental visualizations and numerical simulations were carried out to investigate the bubble generation mechanisms in a microchannel with double flow junctions. Two kinds of flow patterns could be observed from the experiments and simulations: slug-bubble flow and split flow. When 0.00554 < Ca 2 < 0.025 and 0.25 < Q G /Q L < 6, slug-bubble flow can be observed. When Ca 2 < 0.00554 and 6 ≤ Q G /Q L ≤ 8, split flow will occur. Bubble length and velocities were also analyzed experimentally and theoretically. The relationship between bubble length, Ca and flow rate ratio Q G /Q L was obtained by regression, and the correlation could predict the data within an RMS error of 20%. Bubble velocity data correlated with the drift flux model showed that the distribution parameter of the two flow junctions C 01 andC 02 had values of 1.0654 and 1.1123, respectively.

Effects of a Dynamic Injection Flow Rate on Slug Generation in a Cross-Junction Square Microchannel

“…They proposed a model to predict the distributions very well. Liu et al [4] investigated the effects of capillary number and flow rate ratio on the slug-bubble flow by conducting experiments and numerical simulations. They developed a correlation to describe the relationship between bubble length, capillary number and flow rate ratio.…”