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Measurement of shear-induced self-diffusion in concentrated suspensions of spheres

Published online by Cambridge University Press:  21 April 2006

David Leighton
Affiliation:
Department of Chemical Engineering, Stanford University, Stanford, CA 94305–5025, USA Present address: Department of Chemical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA.
Andreas Acrivos
Affiliation:
Department of Chemical Engineering, Stanford University, Stanford, CA 94305–5025, USA

Abstract

A novel technique is presented for determining the coefficient of shear-induced particle self-diffusion in concentrated suspensions of solid spheres, which relies on the fact that this coefficient can be computed from the measured variations in the time taken by a single marked particle in the suspension to complete successive circuits in a Couette device. Since this method does not involve the direct measurement of the lateral position of the marked particle, it requires a much simpler experiment than that used by Eckstein, Bailey & Shapiro (1977) which is shown to be constrained by wall effects at high particle concentration. The diffusion coefficient thus determined was found to be proportional to the product γa2, where γ is the shear rate and a the particle radius, and to have the asymptotic form 0.5γa2ϕ2 in the dilute limit when the particle concentration ϕ → 0.

Type
Research Article
Copyright
© 1987 Cambridge University Press

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References

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