Skip to main content Accessibility help
×
Home

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

  • A. W. Chow (a1), S. W. Sinton (a1) and J. H. Iwamiya (a1)

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.

Copyright

References

Hide All
1. Leighton, D. and Acrivos, A., J. Fluid Mech. 81, 415 (1987)
2. Rutgers, I. R., Rheol. Acta, 2, 305 (1962)
3. Thomas, D. G., J. Colloid Sci., 20, 267 (1965)
4. Mondy, L. A., Graham, A. L., and Gottlieb, M., Proceedings of the Xth International Congress on Rheology, Sydney, Australia, 2, 137 (1988)
5. Chow, A. W., Sinton, S. W., Iwamiya, J. H., and Stephens, T. S., “Shear-Induced Particle Migration in a Couette Viscometer: NMR Imaging and Stress Measurements,” manuscript in preparation.
6. Chow, A. W., Sinton, S. W., and Iwamiya, J. H., “Direct Observation of Particle Microstructure in Concentrated Suspensions during the Falling-Ball Experiment,” J. Rheol., 38, Jan 1993
7. Gadala-Maria, F. and Acrivos, A., J. Rheol., 24, 799 (1980)
8. Abbott, J. R., Tetlow, N., Graham, A. L., Altobelli, S. A., Fukushima, E., Mondy, L. A., and Stephens, T. S., 35, 773 (1991)

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

  • A. W. Chow (a1), S. W. Sinton (a1) and J. H. Iwamiya (a1)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed