Journal article 570 views
A new constitutive model for worm-like micellar systems – Numerical simulation of confined contraction–expansion flows
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Hamid Tamaddon-Jahromi
Journal of Non-Newtonian Fluid Mechanics, Volume: 204, Pages: 7 - 21
Swansea University Authors:
Michael Webster , Hamid Tamaddon-Jahromi
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DOI (Published version): 10.1016/j.jnnfm.2013.11.001
Abstract
This hybrid finite element/volume study is concerned with the modelling of worm-like micellar systems, employing a new micellar thixotropic constitutive model with viscoelasticity within network-structure construction-destruction kinetics. The work focuses on steady-state solutions for axisymmetric,...
| Published in: | Journal of Non-Newtonian Fluid Mechanics |
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| Published: |
2014
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa24192 |
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| Abstract: |
This hybrid finite element/volume study is concerned with the modelling of worm-like micellar systems, employing a new micellar thixotropic constitutive model with viscoelasticity within network-structure construction-destruction kinetics. The work focuses on steady-state solutions for axisymmetric, rounded-corner, 4:1:4 contraction-expansion flows. This has importance in industrial and healthcare applications such as in enhanced oil-reservoir recovery. Material functions for the micellar models (time-dependent, thixotropic) have been fitted to match two different extensional configurations of the exponential Phan-Thien/Tanner (PTT) model (rubber network-based, non-thixotropic). This covers mild and strong-hardening response, and re solvent fraction, highly-polymeric (=1/9) and solvent-dominated (=0.9) fluids. Solution results are described through normalised Excess Pressure Drop (EPD), vortex intensity and stream function, stress (N1 & N2), and f-functional data. EPD predictions with the new micellar models prove to be consistent (at low rates, some rising) with Newtonian results, contrary to the base-reference modified Bautista-Manero (MBM) results. Markedly different vortex intensity trends are found in comparing micellar and EPTT solutions, which correspond with N2-N1 and f data. In order to address the highly-elastic regime for thixotropic materials, a convoluted approach between EPPT and micellar models has been proposed. Here, numerically stable solutions are reported for impressively large We up to 300 and new vortex structures are revealed. |
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| Keywords: |
Rising excess pressure drop, wormlike micelles, complex flows, viscoelasticity, high-elasticity solutions, Bautista-Manero models, numerical simulation, hybrid finite element/volume method, enhanced oil-recovery |
| College: |
Faculty of Science and Engineering |
| Start Page: |
7 |
| End Page: |
21 |