Hodgkinson, R. orcid.org/0000-0001-6473-5485, Chaffin, S.T., Zimmerman, W.B.J. orcid.org/0000-0001-7123-737X et al. (2 more authors) (2022) Extensional flow affecting shear viscosity: experimental evidence and comparison to models. Journal of Rheology, 66 (4). pp. 793-809. ISSN 0148-6055
Abstract
The effect of extensional flow on apparent shear viscosity has never previously been directly measured nor is it often considered. Here, for the first time, through using a novel flow configuration (two-phase shear response under extensional flow), we have directly measured the effect extensional flow has on the apparent shear viscosity of a viscoelastic polymer solution in a controlled and kinematically mixed manner. We show, via a control transient shear experiment, that the apparent shear viscosity of the solution under mixed deformation depends not only on the shear rate but also on the extension rate and their relative direction: shear thinning being enhanced by parallel and reduced by perpendicular extensional flow, respectively. A 62% reduction in apparent viscosity with parallel extension was seen in this work. We then test the ability of the commonly used Giesekus and Carreau–Yasuda (incorporating generalized shear rate) models to predict the effect of extension rate on apparent shear viscosity against our data. The Giesekus model was found to predict the correct qualitative behavior under both parallel and perpendicular extensional flow, and depending on the fitting parameters, also provided a loosely quantitative agreement. Conversely, the generalized shear rate description does not capture the qualitative behavior, with the most significant errors occurring for perpendicular extension (i.e., expansion) flows. This work emphasizes the rarely noted shortcomings of the latter approach when used for experimental analysis and engineering design when extensional flows are additionally present.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
Keywords: | Finitely extensible nonlinear elastic; Refractive-index matching; Extensional flow measurement; Flow visualization; Multiphase flows; Polymer solution flows; Rheology and fluid dynamics; Shear thinning; Viscoelasticity; Viscosity |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Chemical and Biological Engineering (Sheffield) |
Funding Information: | Funder Grant number ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL EP/I019790/1 ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL EP/K005693/1 EUROPEAN COMMISSION - HORIZON 2020 713475 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 12 Jan 2024 11:31 |
Last Modified: | 12 Jan 2024 11:31 |
Published Version: | http://dx.doi.org/10.1122/8.0000380 |
Status: | Published |
Publisher: | Society of Rheology |
Refereed: | Yes |
Identification Number: | 10.1122/8.0000380 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:207517 |