Nonlinear Shear and Extensional Flow Dynamics of Wormlike Surfactant Solutions

By B. Yesi̇lata, Christian Clasen, G. H. McKinley. 2006

137 citations recorded by the source corpus.

Nonlinear shear and extensional flow dynamics of a wormlike micellar solution based on erucyl bis(2-hydroxyethyl) methyl ammonium chloride (EHAC) are reported here. The influences of surfactant (EHAC) and salt (NH4Cl) concentrations on the linear viscoelastic parameters are determined using small amplitude oscillatory shear experiments. The steady and time-dependent shear rheology is determined in a double gap Couette cell, and transient extensional flow measurements are performed in a capillary breakup extensional rheometer (CABER). In the nonlinear shear flow experiments, the micellar fluid samples show strong hysteretic behavior upon increasing and decreasing the imposed shear stress due to the development of shear-banding instabilities. The non-monotone flow curves of stress versus shear rate can be successfully modeled in a macroscopic sense by using the single-mode Giesekus constitutive equation. The temporal evolution of the flow structure of the surfactant solutions in the Couette flow geometry is analyzed by instantaneous shear rate measurements for various values of controlled shear stress, along with FFT analysis. The results indicate that the steady flow bifurcates to a global time-dependent state as soon as the shear-banding/hysteresis regime is reached. Increasing the salt–surfactant ratio or the temperature is found to stabilize the flow, and corresponds to decreasing values of anisotropy factor in the Giesekus model. Finally, we have investigated the dynamics of capillary breakup of the micellar fluid samples in uniaxial extensional flow. The filament thinning behavior of the micellar fluid samples is also accurately predicted by the Giesekus constitutive equation. Indeed quantitative agreement between the experimental and numerical results can be obtained providing that the relaxation time of the wormlike micellar solutions in extensional flows is a factor of three lower than in shear flows.

Subfields: Computational Mechanics, Fluid Flow and Transfer Processes, Organic Chemistry

View Paper: https://www.semanticscholar.org/paper/4c8ac67a6d8169ff743f703aae819f63df0adfad

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In Computational Mechanics

In Fluid Flow and Transfer Processes

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Citations in the corpus

Gradient and vorticity banding (2008, background): “…and Callaghan 1999; Fischer and Callaghan 2001; Britton et al. 1999; Salmon et al. 2003a; Herle et al. 2005; Hu and Lips 2005; Liberato et al. 2006; Yesilata et al. 2006; Miller and Rothstein 2007; and Manneville et al. 2007 and theoretical models for worms concerned with banding in Spenley et al.…”
Extensional rheology of a shear-thickening cornstarch and water suspension (2010, methodology): “Capillary breakup extensional rheometry (CaBER) measurements have become an increasingly common technique for determining the extensional rheology of the less-concentrated and less-viscous fluids (Anna and McKinley 2001; Bazilevsky et al. 1990 ;C lasen et al. 2006; Entov and Hinch 1997; Kojic et al.”
Shear-Induced Transitions and Instabilities in Surfactant Wormlike Micelles (2009, unknown): “(a) [28,135,136,140,141,145,146,147,148,149,150,151,152,153,154], (b) [33,137,138,139,150, 151,155,156,157,158,159,160,161,162,163,164,165], (c) [166,167,168,169,170,171,172], (d) [173], (e) [23,30,72,154,174,175,176,177,178,179,180,181,182,183,184,185,186,187], (f) [30, 188,189,190,191], (g) [144,1”
Recent experimental probes of shear banding (2008, background): “Further research effort established the generality of this peculiar feature on other wormlike micelle systems [21, 22, 23, 38, 77, 138, 185, 202].”