On the measurement of the relative viscosity of suspensions
- The Levich Institute and Department of Chemical Engineering, The City College of the City University of New York, New York, New York 10031 (United States)
The relative viscosity of a suspension of rigid, noncolloidal particles immersed in a Newtonian fluid was measured in a Couette device and was found to be shear thinning even for values of the solids fraction as low as 20%. Although such behavior was reported previously, no satisfactory explanation appears to have been given thus far. It shall be shown presently, however, that, at least for our systems, this shear-thinning effect was due to a slight mismatch in the densities of the two phases. Moreover, the apparent relative viscosities measured in our apparatus were found to be in excellent agreement with those predicted theoretically using a model, originally proposed by Leighton and Acrivos [Chem. Eng. Sci. [bold 41], 1377--1384 (1986)], to describe viscous resuspension, according to which the measured relative viscosity should depend on the bulk particle concentration and on the dimensionless Shields number [ital A], and should attain its correct value for a well-mixed suspension only as [ital A][r arrow][infinity]. The predictions of this model are also in excellent agreement with the measured transient response of the apparent relative viscosity due to a sudden change in the shear rate.
- DOE Contract Number:
- FG02-90ER14139
- OSTI ID:
- 7143135
- Journal Information:
- Journal of Rheology; (United States), Vol. 38:5, Issue 5; ISSN 0148-6055
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
SUSPENSIONS
VISCOSITY
CONCENTRATION RATIO
GLYCEROL
METHACRYLATES
MULTIPHASE FLOW
SHEAR PROPERTIES
TRANSIENTS
WATER
ALCOHOLS
CARBOXYLIC ACID SALTS
DISPERSIONS
FLUID FLOW
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
MECHANICAL PROPERTIES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
661300* - Other Aspects of Physical Science- (1992-)