Concentrated phase emulsion with multi-core morphology under shear: A numerical study

TL;DR

This numerical study explores the complex dynamic behaviors of concentrated multi-core emulsions under shear flow, revealing multiple steady states and detailed core motion patterns within microfluidic channels.

Contribution

The paper introduces a comprehensive numerical analysis of multi-core emulsion dynamics under shear, identifying new steady states and detailed core motion behaviors.

Findings

Solid-like planetary core motion at low shear rates

Alignment and motionless cores at high shear rates

Formation of elliptical ring chains resembling treadmilling structures

Abstract

We numerically study the dynamic behavior under a symmetric shear flow of selected examples of concentrated phase emulsions with multi-core morphology confined within a microfluidic channel. A variety of new nonequilibrium steady states is reported. Under low shear rates, the emulsion is found to exhibit a solid-like behavior, in which cores display a periodic planetary-like motion with approximately equal angular velocity. At higher shear rates two steady states emerge, one in which all inner cores align along the flow and become essentially motionless and a further one in which some cores accumulate near the outer interface and produce a dynamical elliptical-shaped ring chain, reminiscent of a treadmilling-like structure, while others occupy the center of the emulsion. A quantitative description in terms of i) motion of the cores, ii) rate of deformation of the emulsion and iii) structure of the fluid flow within the channel is also provided.