TY - JOUR
T1 - Pressure-driven microfluidic droplet formation in Newtonian and shear-thinning fluids in glass flow-focusing microchannels
AU - Chen, Qi
AU - Li, Jingkun
AU - Song, Yu
AU - Chen, Bin
AU - Christopher, David M
AU - Li, Xuefang
N1 - Funding Information:
Funding: This study was supported by the Foshan-Tsinghua Innovation Special Fund (FTISF) (No.2019THFS0114).
Publisher Copyright:
© 2021
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/7/1
Y1 - 2021/7/1
N2 - Pressure-driven microdroplet formation was experimentally investigated in glass flow-focusing devices using micro-imaging. The observations illustrated the effects of some important factors affecting the droplet formation, including the channel geometry, two-phase flow rates and non-Newtonian behavior of the continuous phase. Although the droplet formation dynamics showed some different characteristics in different geometries, self-similarities of the dispersed thread were found in both devices for various initial conditions by normalizing the thread length and time. When power-law shear-thinning fluids were used as the continuous phase, the growth of the dispersed thread was still self-similar, but the relationship became linear rather than power-law as with the Newtonian continuous phase. The droplet shape also changed for droplet generated in shear-thinning fluids, so a deformation index (D.I.) was defined to describe the shape differences. Finally, a previously presented prediction model was validated by the experimental data with good agreement.
AB - Pressure-driven microdroplet formation was experimentally investigated in glass flow-focusing devices using micro-imaging. The observations illustrated the effects of some important factors affecting the droplet formation, including the channel geometry, two-phase flow rates and non-Newtonian behavior of the continuous phase. Although the droplet formation dynamics showed some different characteristics in different geometries, self-similarities of the dispersed thread were found in both devices for various initial conditions by normalizing the thread length and time. When power-law shear-thinning fluids were used as the continuous phase, the growth of the dispersed thread was still self-similar, but the relationship became linear rather than power-law as with the Newtonian continuous phase. The droplet shape also changed for droplet generated in shear-thinning fluids, so a deformation index (D.I.) was defined to describe the shape differences. Finally, a previously presented prediction model was validated by the experimental data with good agreement.
KW - Flow-focusing devices
KW - Microdroplet formation
KW - Newtonian fluids
KW - Self-similarity
KW - Shear-thinning fluids
U2 - 10.1016/j.ijmultiphaseflow.2021.103648
DO - 10.1016/j.ijmultiphaseflow.2021.103648
M3 - Article
SN - 0301-9322
VL - 140
JO - International Journal of Multiphase Flow
JF - International Journal of Multiphase Flow
M1 - 103648
ER -