Breakup dynamics for droplet formation in shear-thinning fluids in a flow-focusing device

• Published in: Chemical engineering science Vol. 176; pp. 66 - 76
• Main Authors: Du, Wei, Fu, Taotao, Duan, Yingfeng, Zhu, Chunying, Ma, Youguang, Li, Huai Z.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 02.02.2018; Elsevier
• Subjects: Breakup; Chemical and Process Engineering; Droplet; Engineering Sciences; Fluids mechanics; Interface; Mechanics; Microfluidics; Shear-thinning fluids; Shear-thinning fluids; Breakup; Droplet; Microfluidics; Interface
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2017.10.019

[Display omitted] •Shear-thinning effect on thread breakup in a flow-focusing device was studied.•Four breakup stages were observed in the rupture of the shear-thinning dispersed thread.•The dynamics in stretching stage is similar to that in viscous regime.•The dynamics in pinch-off stage is similar to that in Stokes regime.•The breakup dynamics is almost unaffected by the shear-thinning rheological properties. The breakup dynamics of the dispersed thread for droplet formation in shear-thinning fluids in a flow-focusing device was highlighted. The breakup process of the shear-thinning dispersed thread could be divided into four stages: the droplet growth stage and the squeezing stage, both of them are dominated by the squeezing pressure, the stretching stage controlled by the viscous stresses of dispersed phase and the surface tension, and the pinch-off stage controlled by the viscous stresses of both phases and the surface tension. The breakup dynamics of the dispersed thread for the shear-thinning fluids in each stage is very similar to that of the constant viscosity Newtonian liquids, signifying that the breakup is almost unaffected by the shear-thinning rheological properties.