Numerical investigation of Taylor bubble flow distribution in multi cross-branched microchannels

Abstract

A numerical study was conducted using computational fluid dynamics software to investigate the phase distribution of Taylor bubble flow in multi cross -branched microchannels and also to investigate the bubble breaking behaviour at the two junctions.A new design is put forward which composed of flow focusing inlet section for formation of bubbles and two bubble breakup junctions composed of a cross-junction and a T-junction. Glycerine and Nitrogen gas were used as the continuous phase and dispersedphase, respectively for the study. The study was divided into four separate cases by changing a particular parameter and keeping all others constant. The different parameters such as gas-liquid flow rate ratio () varied from 0.13 to 0.56, angle of branch channels )varied from 60° to 120°, width of branch channels (wB and width of secondary main channel (wS each cases respectively. From this study it was observed that the phase distribution characteristics were highly influenced by the gas-liquid flow rate ratio. The phase distribution will be more uniform with increase in gas-liquid flow rate ratio. In this study of bubble breakup behaviour the progression of bubble breakup morphology and the distribution of total pressure in the flow field were analysed at both the junctions. The results shows that the breakup type occurring at the cross-junction was always the same but at the T-junction it was observed that along with the same bubble breakup type two other types of non-breakup phenomenon were observed during the bubble flows through the cross-junction and the T-junctions under different cases. Usually the bubble breakup process undergoes the expansion, squeeze and post-breakup stages, while at the T-junction the two non-breakup process experiences expansion, merging and pushing stages and in some cases it experiences two different stages of pushing that happens simultaneously