Flow of entangled wormlike micellar fluids: mesoscopic simulations, rheology and micro-PIV experiments

E.S. Boek, J.T. Padding, V.J. Anderson, W.J. Briels, J.P. Crawshaw

Research output: Contribution to journalArticleAcademicpeer-review

34 Citations (Scopus)
257 Downloads (Pure)

Abstract

There is a great need for understanding the relationship between the structure and chemistry of surfactants forming wormlike micelles, and their macroscopic flow properties. Available macroscopic Rheological Equations of State (REoS) are often inadequate to predict flow behaviour in complex geometries or even to describe the full set of rheological measurements. In this paper, we show how the link between surfactant structure and rheology can be explored through the use of mesoscopic particulate simulations. We describe the development of a realistic Brownian Dynamics model, where the persistence length of the micelle is the smallest length scale. Most of the parameters for the BD model are obtained from atomistic Molecular Dynamics simulations to establish the link to the chemistry of the surfactant. As a preliminary result, we calculate the shear viscosity of a solution of entangled wormlike micelles as a function of increasing shear rate. The results can be approximately mapped on an experimental flow curve for this particular system, using a mean field scaling relationship. Finally, as our motivation in this work is to understand the flow of wormlike micellar fluids in porous media, we give preliminary experimental results for the flow in an expansion-contraction capillary using micro Particle Image Velocimetry (μ-PIV). This demonstrates the complex response of these fluids in non-viscometric flows and the challenges they pose to any predictive simulation model.
Original languageEnglish
Pages (from-to)11-21
Number of pages11
JournalJournal of non-newtonian fluid mechanics
Volume146
Issue number1-3
DOIs
Publication statusPublished - 2007
Event3rd Annual European Rheology Conference, AERC 2006 - Hersonisos, Crete, Greece
Duration: 27 Apr 200629 Apr 2006
Conference number: 3

Keywords

  • Complex fluids
  • Molecular dynamics
  • Rheology
  • Entanglements
  • Brownian dynamics
  • Constitutive equation
  • Wormlike micelles

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