Publication
Title
Influence of confinement on the steady state behavior of single droplets in shear flow for immiscible blends with one viscoelastic component
Author
Abstract
By using a counter rotating plate-plate device, single droplets in shear flow have been microscopically studied at confinement ratios ranging from 0.1 to 0.75. The droplet-to-matrix viscosity ratio was fixed at 0.45 and 1.5. Results are presented for systems with a viscoelastic Boger fluid matrix or a viscoelastic Boger fluid droplet, at a Deborah number of 1. Although the separate effects of confinement and component viscoelasticity on droplet dynamics in shear flow are widely studied, we present the first systematic experimental results on confined droplet deformation and orientation in systems with viscoelastic components. Above a confinement ratio of 0.3, wall effects cause an increase in droplet deformation and orientation, similar to fully Newtonian systems. To describe the experimental data, the Shapira-Haber theory [Shapira, M., and S. Haber, Int. J. Multiph. Flow 16, 305-321 (1990)] for confined slightly deformed droplets in Newtonian-Newtonian systems is combined with phenomenological bulk models for systems containing viscoelastic components [Maffettone, P. L., and F. Greco, J. Rheol 48, 83-100 (2004); M. Minale, J. Non-Newtonian Fluid Mech. 123, 151-160 (2004)]. The experimental results are also compared to a recent model for confined droplet dynamics in fully Newtonian systems [M. Minale, Rheol. Acta 47, 667-675 (2008)]. For different values of the viscosity ratio, component viscoelasticity and Ca-number, good agreement was generally obtained between experimental results and predictions of one or more models. However, none of the models can accurately describe all experimental data for the whole range of parameter values.
Language
English
Source (journal)
Journal of rheology / Society of Rheology [New York] - New York, N.Y.
Publication
New York, N.Y. : 2009
ISSN
0148-6055
Volume/pages
53:6(2009), p. 1403-1424
ISI
000273805600009
Full text (Publishers DOI)
UAntwerpen
Faculty/Department
Publication type
Subject
External links
Web of Science
Record
Identification
Creation 26.09.2013
Last edited 22.04.2017