Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-27T01:32:07.212Z Has data issue: false hasContentIssue false
  • English
  • Français

Rheology and Microstructure of Concentrated Suspensions

Published online by Cambridge University Press:  28 February 2011

Lisa A. Mondy  and
Alan L. Graham
Lisa A. Mondy
Affiliation:
Sandia National Laboratories, Division 1511, Albuquerque, New Mexico 87185
Alan L. Graham
Affiliation:
Los Alamos National Laboratory, MEE-4, Los Alamos, New Mexico 87545
Get access

Abstract

We give an overview of some of the experiments currently underway to study the coupling of the microstructure and rheology of concentrated suspensions. Nuclear magnetic resonance imaging, real-time x-ray radiography, and refractive index matching allow the viewing of particles in concentrated suspensions. Both shear flow experiments and falling ball rheometry are reviewed. In the slow flow of these suspensions of large, hard, particles in a viscous Newtonian fluid, colloidal forces are negligible and hydrodynamic forces dominate.

Large local concentration changes are shown to occur rapidly in suspensions of uniform spheres subjected to flow between concentric rotating cylinders. Suspensions of spheres with a bimodal size distribution not only show similar phenomena, but also exhibit particle separation according to size. In addition, the large particles in the bimodal suspension migrate into ordered, concentric, cylindrical sheets, parallel to the axis of the cylinders. These sheets of particles rotate relative to each other. The particle migration and structure formation induced by this inhomogeneous shear flow is believed to be responsible for torque reductions and other anomalous behavior witnessed during the rheological testing of concentrated suspensions reported in the literature. Thus, suspensions may not always be characterized by a viscosity that is a scalar material property.

Suspensions of fibers also show markedly different rheological properties when the particles are aligned by flow. Falling ball rheometry is shown to be an effective tool to determine the bulk viscosity of a suspension while only slightly influencing the microstructure. This is illustrated by showing that falling ball rheometry can isolate the effect of orientation on the viscosity of a suspension of fibers.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 180: Symposium A – Better Ceramics Through Chemistry IV , 1990 , 173
Copyright
Copyright © Materials Research Society 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Leighton, D. and Acrivos, A., J. Fluid Mech., 181, 415 (1987).Google Scholar
2. Surovec, R. D., Husband, D. M., Stephens, T. S., and Graham, A. L., “Reproducibility in Measuring Rheology of Highly Concentrated Suspensions,” JANNAF Propellant Development Characterization Subcommittee 1989 Annual Meeting, Laurel, Maryland, 1989.Google Scholar
3. Salem, A. J. and Fuller, G. G., J. Colloid Interface Sci., 108, 149 (1985).Google Scholar
4. Ackerson, B. J. and Pusey, P. N., Phys. Rev. Lett., 61, 1033 (1988).Google Scholar
5. Majors, P. D., Givler, R. C., and Fukushima, E., J. Magnetic Resonance, 85, 235 (1989).Google Scholar
6. Morris, P. G., Nuclear Magnetic Resonance Imaging in Medicine and Biology, Clarendon Press, Oxford, 1986.Google Scholar
7. Abragam, A., The Principles of Nuclear Magnetism, Clarendon Press, Oxford, 1961.Google Scholar
8. Watkins, J. C. and Fukushima, E., Rev. Sci. Instrum., 59, 926 (1988).Google Scholar
9. Koch, D. L., Phys. Fluids A, 1, 1742 (1989).Google Scholar
10. Walton, J. S., “Close-Range Cine-Photogrammetry,” Thesis, Penn State University (1981).Google Scholar
11. Graham, A. L., Mondy, L. A., and Powell, R. L., “Applications of Real-Time Radiography to Rheological Characterization and Processing Dynamics,” JANNAF Propellant Development Characterization Subcommittee 1987 Annual Meeting, Laurel, Maryland, 1987.Google Scholar
12. Bird, R. B., Stewart, W. E., and Lightfoot, E. N., Transport Phenomena (John Wiley & Sons, New York, 1960), p. 59.Google Scholar
13. Bohlin, T., Trans. R. Inst. Tech. (Stockholm), No. 155.Google Scholar
14. Mondy, L. A., Graham, A. L., and Jensen, J. L., J. Rheol., 30, 1031 (1986).Google Scholar
15. Milliken, W. J., Mondy, L. A., Gottlieb, M., Graham, A. L., and Powell, R. L., PCH Physico Chemical Hydrodynamics, 11, 341 (1989).Google Scholar
16. Mondy, L. A., Graham, A. L., and Gottlieb, M., “Microrheological Observations on the Onset of Non-Newtonian Behavior in Suspensions,” Xth International Congress on Rheology, Sydney, Australia, August 1988.Google Scholar
17. Thomas, D. G., J. Colloid Sci., 20, 267 (1965).Google Scholar
18. Milliken, W. J., Gottlieb, M., Graham, A. L., Mondy, L. A., and Powell, R. L., J. Fluid Mech., 202, 217 (1989).Google Scholar
19. Powell, R. L., Mondy, L. A., Stoker, G. G., Milliken, W. J., and Graham, A. L., J. Rheol., 33, 1173 (1989).Google Scholar
20. Mondy, L. A., Morrison, T. G., Graham, A. L., and Powell, R. L., Int. J. Multiphase Flow, (in press 1990).Google Scholar
21. Doi, M. and Edwards, S. F., J. Chem. Soc. Faraday Trans. II, 74, 918 (1978).Google Scholar
22. Keep, G. T. and Pecora, R., Macromol.,18, 1167 (1985).Google Scholar
23. Magda, J. J., Davis, H. T., and Tirrell, M., J. Chem. Phys., 85, 6674 (1986).Google Scholar
24. Brenner, H., Intl. J. Multiphase Flow, 1, 195 (1974).Google Scholar
25. Haber, S. and Brenner, H., J. Colloid Interface Sci., 97, 496 (1984).Google Scholar
26. Morrison, T. G., M.S. thesis, University of California - Davis, 1989.Google Scholar
27. Ganani, E. and Powell, R. L., J. Rheol, 30, 995 (1986).Google Scholar