Influence of surfactants on the slug flow of immiscible liquids in a curved microchannel
A.V. Kovalev1,2, A.A. Yagodnitsyna1,2, A.V. Bilsky1
1Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: flow of immiscible liquids, slug flow regime, surfactants, curved microchannel
Abstract
The dynamics of a slug flow in immiscible liquids remains incompletely understood due to the complex effects of channel geometry and the properties of the working fluids. The presence of surfactants in the system further complicates the problem. This work deals with the effect of an water solution of Tween 20 surfactant on the dynamics of a slug flow in a curved microchannel. Situations with surfactant concentrations below and above the critical concentration of micelle formation are considered. Regime maps are plotted, and three regimes of water phase dispersion are identified. It is shown that increasing the surfactant concentration leads to stabilization of slug interfaces in straight sections, while the probability of slug disintegration in curved sections increases due to reduced interfacial tension and intense mixing of the surfactant within the slugs. The decisive influence of the surfactant concentration relative to the critical concentration of micelle formation on the dynamics of microdroplet detachment processes in straight and curved sections of the channel is revealed.
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