A numerical investigation on the drainage of a surfactant-modified water droplet in paraffin oil

Lekhlifi, Adil; Fanzar, Abdelaziz; Antoni, Mickaël

doi:10.1016/j.cis.2015.02.005

Cited by 2 publications

(1 citation statement)

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“…Since of the various effects of surfactants and their high nonlinearity, nonuniform interfacial tension problems involving a mobile interface remain very challenging analytically. , This difficulty is alleviated for numerical simulations, and a wealth of models of single droplets or bubbles covered with an insoluble ,− or soluble surfactant ,− are available. Nevertheless, the effects of surfactant nonuniform coverage on the droplet formation in microfluidic channels have yet to be investigated.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Surfactant Dynamics during Emulsification in a T-Junction Microchannel

et al. 2018

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Microchannel emulsification requires large amounts of surfactant to prevent coalescence and improve emulsions lifetime. However, most numerical studies have considered surfactant-free mixtures as models for droplet formation in microchannels, without taking into account the distribution of surfactant on the droplet surface. In this paper, we investigate the effects of nonuniform surfactant coverage on the microfluidic flow pattern using an extended lattice-Boltzmann model. This numerical study, supported by micro-particle image velocimetry experiments, reveals the likelihood of uneven distribution of surfactant during the droplet formation and the appearance of a stagnant cap. The Marangoni effect affects the droplet breakup by increasing the shear rate. According to our results, surfactant-free and surfactant-rich droplet formation processes are qualitatively different, such that both the capillary number and the Damköhler number should be considered when modeling the droplet generation in microfluidic devices. The limitations of traditional volume and pressure estimation methods for determining the dynamic interfacial tension are also discussed on the basis of the simulation results.

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