Open Access

ARTICLE

Viscoelastic Drop Deformation in a Micro-Contraction

by Malcolm R. Davidson¹, Dalton J.E. Harvie¹

1 The University of Melbourne, Department of Chemical and Biomolecular Engineering, Melbourne, Australia

Fluid Dynamics & Materials Processing 2011, 7(3), 317-328. https://doi.org/10.3970/fdmp.2011.007.317

Abstract

A volume-of-fluid numerical method, adapted by the authors [Harvie, Cooper-White and Davidson (2008)] to simulate the flow of viscoelastic fluids, is used to predict deformation of a viscoelastic droplet carried by an immiscible Newtonian liquid through an axisymmetric microfluidic contraction-expansion. Values of the capillary number and elasticity number are chosen based on corresponding values for a rectangular contraction for which a reentrant cavity at the rear of the drop and subsequent encapsulation behaviour was observed experimentally by Harvie, Cooper-White and Davidson (2008). A reentrant cavity, similar to the observed one, is predicted; however, encapsulation is not achieved. Unexpectedly, a narrow cavity at the centre of the forward face of the drop exiting the contraction is also predicted for low capillary number and high elasticity number. The forward cavity eventually completely penetrates the drop so that it forms a torus.

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