Issue 44, 2019

Lateral migration of viscoelastic droplets in a viscoelastic confined flow: role of discrete phase viscoelasticity

Abstract

The cross-stream motion of viscoelastic droplets in viscoelastic fluids has received little attention since the classical study of migration of drops in a second order fluid. In this work, going beyond the existing classical theory, we experimentally elucidate the effect of drop-to-medium viscosity ratio k and elasticity ratio ξ on wall and center migration of viscoelastic droplets in a Poiseuille flow of a viscoelastic medium (PVP) at low Reynolds numbers (Re ≪ 1). We observed a contrasting migration behavior of Newtonian and viscoelastic droplets having the same viscosity ratios and propose the presence of a lift force FVD due to the viscoelasticity of the droplet phase. We use analytical scaling and empirical modelling to show that the force FVD scales with a prefactor that depends upon the Weissenberg number WiD and drop-to-medium viscosity ratio k and elasticity ratio ξ. Further, we utilize the proposed force for sorting of viscoelastic and Newtonian droplets.

Graphical abstract: Lateral migration of viscoelastic droplets in a viscoelastic confined flow: role of discrete phase viscoelasticity

Supplementary files

Article information

Article type
Paper
Submitted
19 Jul 2019
Accepted
05 Oct 2019
First published
07 Oct 2019

Soft Matter, 2019,15, 9003-9010

Lateral migration of viscoelastic droplets in a viscoelastic confined flow: role of discrete phase viscoelasticity

S. Hazra, S. K. Mitra and A. K. Sen, Soft Matter, 2019, 15, 9003 DOI: 10.1039/C9SM01469A

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