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Nuclear Magnetiic Resonance Imaging (NMRI) of Flow-Induced Microstructure of Concentratied Suspensions

Published online by Cambridge University Press:  15 February 2011

A. W. Chow ,
S. W. Sinton  and
J. H. Iwamiya
A. W. Chow
Affiliation:
Lockheed Palo Alto Research Laboratory, 3251 Hanover St., Palo Alto, CA 94304
S. W. Sinton
Affiliation:
Lockheed Palo Alto Research Laboratory, 3251 Hanover St., Palo Alto, CA 94304
J. H. Iwamiya
Affiliation:
Lockheed Palo Alto Research Laboratory, 3251 Hanover St., Palo Alto, CA 94304
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Abstract

The application of nuclear magnetic resonance flow imaging (NMRI) to the study of Couette and falling-ball viscometry of solid/liquid suspensions is described. The suspension consisted of non-Brownian, monodisperse, neutrally-buoyant spheres of 50 vol%. NMRI data demonstrated flow-induced changes in the particle distribution in the suspension that strongly influence the accuracy in viscosity measurements using these flow geometries. In Couette flow, direct correlation between stress measurements and particle concentrations at various locations in the flow cell as a function of shear strain can be made. Our data directly confitrm the shearinduced particle migration theory proposed by Leighton and Acrivos.[1] In the falling-ball experiments, increased particle concentration at the leading edge and decreased concentration at the trailing edge of the ball was observed when the falling ball is big compared to the cylinder containing the suspension. This change in particle distribution can be directly related to the changes in fall velocity of the ball as a function of position in the cylinder.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 289: Symposium M – Flow and Microstructure of Dense Suspensions , 1992 , 95
Copyright
Copyright © Materials Research Society 1993

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References

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