Shear flow of wormlike micelles in pipe and cylindrical Couette geometries as studied by nuclear magnetic resonance microscopy
作者:
R. W. Mair,
P. T. Callaghan,
期刊:
Journal of Rheology
(AIP Available online 1997)
卷期:
Volume 41,
issue 4
页码: 901-924
ISSN:0148-6055
年代: 1997
DOI:10.1122/1.550864
出版商: The Society of Rheology
关键词: Wormlike micelles;NMR imaging;Slip;Banding
数据来源: AIP
摘要:
The nonlinear viscosity of the wormlike surfactant system cetyl pyridinium chloride/sodium salicylate (60 mM/100 mM in water) has been investigated in both pipe and cylindrical Couette geometries, using nuclear magnetic resonance to image both velocity and diffusion. In pipe flow we observe transitions from Newtonian to non-Newtonian viscosity, to spurt, to unstable flow, and then to a regime where fluctuations are rapid on the timescale of a few milliseconds. In the Couette cell we observe apparent slip at the inner wall as well as a high shear rate band located away from the wall in the body of the fluid. The banding phenomenon, which has its counterpart in the pipe flow, is consistent with double valuedness in the stress versus rate of strain relationship for this fluid.
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