The rheology of bimodal hard-sphere dispersions

Journal Article · Sun May 01 04:00:00 EDT 1994 · Physics of Fluids; (United States)

DOI:https://doi.org/10.1063/1.868226· OSTI ID:6692912

Chang, C; Powell, R L ^[1]

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1. Department of Chemical Engineering, University of California at Davis, Davis, California 95616 (United States)

The viscosity of a monolayer of a suspension of bimodally distributed hard spheres is determined for area fractions, [phi][sub [ital a]], from 0.15 to 0.74 with different particle size ratios, [lambda] (diameter of large sphere/diameter of small spheres=1, 2, and 4), and different fractions of small spheres of total solids, [xi] (0.07, 0.27, 0.49, 0.64, and 0.83). Particle distributions are generated by a Monte Carlo technique and the hydrodynamic interactions are calculated by Stokesian dynamics. These results, which correspond to the high-frequency dynamic viscosities, are compared with those from the dynamic simulation of hydrodynamically interacting spherical particles [Chang and Powell, J. Fluid Mech. [bold 253], 1 (1993)]. Dynamic simulation is found to yield higher relative viscosities, [eta][sub [ital r]], as compared with the results of Monte Carlo simulation at high concentrations. This results from the absence of long clusters that completely cross a periodic cell in the Monte Carlo simulations that are present in the dynamic simulations. When [phi][sub [ital a]] is normalized by the maximum packing fraction, [phi][sub [ital m]][sup 2-D], all the viscosity data fall onto a master curve. This is the same trend as that found in dynamic simulations, except that the Monte Carlo simulation gives lower relative viscosities for [phi][sub [ital a]]/[phi][sub [ital m]][sup 2-D] [gt] 0.3. When [lambda] and [phi][sub [ital a]] are fixed, [eta][sub [ital r]] decreases as [xi] increases from zero, reaches a minimum, and then increases as [xi][r arrow]1, similar to the trend found in the dynamic simulations. Good agreement is found among the results of two-dimensional simulations, experiments, and three-dimensional simulations for monodispersed suspensions.

• OSTI ID: 6692912
• Journal Information: Physics of Fluids; (United States), Journal Name: Physics of Fluids; (United States) Vol. 6:5; ISSN 1070-6631; ISSN PHFLE6
• Country of Publication: United States
• Language: English

Related Subjects

661300* -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CALCULATION METHODS
DISPERSIONS
DISTRIBUTION FUNCTIONS
FLUID FLOW
FUNCTIONS
HARD-SPHERE MODEL
MONTE CARLO METHOD
MULTIPHASE FLOW
RHEOLOGY
SUSPENSIONS
VISCOSITY