Kalli, M;
Pico, P;
Chagot, L;
Kahouadji, L;
Shin, S;
Chergui, J;
Juric, D;
... Angeli, P; + view all
(2023)
Effect of surfactants during drop formation in a microfluidic channel: a combined experimental and computational fluid dynamics approach.
Journal of Fluid Mechanics
, 961
, Article A15. 10.1017/jfm.2023.213.
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Abstract
The effect of surfactants on the flow characteristics during rapid drop formation in a microchannel is investigated using high-speed imaging, micro-particle image velocimetry and numerical simulations; the latter are performed using a three- dimensional multiphase solver that accounts for the transport of soluble surfactants in the bulk and at the interface. Drops are generated in a flow-focusing microchannel, using silicone oil ( 4.6 mPa s) as the continuous phase and a 52 % w/w glycerol solution as the dispersed phase. A non-ionic surfactant (Triton X-100) is dissolved in the dispersed phase at concentrations below and above the critical micelle concentration. Good agreement is found between experimental and numerical data for the drop size, drop formation time and circulation patterns. The results reveal strong circulation patterns in the forming drop in the absence of surfactants, whose intensity decreases with increasing surfactant concentration. The surfactant concentration profiles in the bulk and at the interface are shown for all stages of drop formation. The surfactant interfacial concentration is large at the front and the back of the forming drop, while the neck region is almost surfactant free. Marangoni stresses develop away from the neck, contributing to changes in the velocity profile inside the drop.
| Type: | Article |
|---|---|
| Title: | Effect of surfactants during drop formation in a microfluidic channel: a combined experimental and computational fluid dynamics approach |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1017/jfm.2023.213 |
| Publisher version: | https://doi.org/10.1017/jfm.2023.213 |
| Language: | English |
| Additional information: | © The Author(s), 2023. Published by Cambridge University Press. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0). |
| Keywords: | Drops and Bubbles: Drops, Micro-/Nano-fluid dynamics: Microfluidics, Multiphase and Particle-laden Flows: Multiphase flow |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10168920 |
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