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Numerical simulation of polydisperse sedimentation: equal-sized spheres

Published online by Cambridge University Press:  26 April 2006

J. M. Revay
Affiliation:
Department of Chemical Engineering, University of Illinois, Urbana. IL 61801. USA
J. J. L. Higdon
Affiliation:
Department of Chemical Engineering, University of Illinois, Urbana. IL 61801. USA

Abstract

This paper describes the results of numerical simulations for polydisperse sedimentation of equal-sized spheres, e.g. particles of different density. Using the Stokesian dynamics algorithm, mobility matrices are computed for random particle configurations and ensemble averages taken to calculate the mean mobility matrices. It is shown that the settling velocities of individual particles species may be expressed in terms of two scalar functions of total volume fraction. These are the selfmobility Mo, (∼ short-time self-diffusion coefficient) and the interaction mobility MI. This latter quality is related to the velocity of a force-free tracer particle in a suspension of identical particles subjected to a unit force. Numerical values for Mo and MI are calculated for a range of volume fractions from ϕ = 0.025 to 0.50. All results show excellent agreement with the dilute theory of Batchelor. Simple algebraic expressions are given which well correlate the numerical results.

Type
Research Article
Copyright
© 1992 Cambridge University Press

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References

Barker, J. A. & Henderson, D. 1971 Monte Carlo values for the radial distribution function of a system of fluid hard spheres. Molec. Phys. 21, 187191.Google Scholar
Batchelor, G. K. 1972 Sedimentation in a dilute dispersion of spheres. J. Fluid Mech. 52, 245268.Google Scholar
Batchlor, G. K. 1976 Brownian diffusion of particles with hydrodynamic interaction. J. Fluid Mech. 74, 129.Google Scholar
Batchelor, G. K. 1982 Sedimentation in a dilute polydisperse system of interacting spheres. Part 1. General theory. J. Fluid Mech. 119, 379408.Google Scholar
Batchelor, G. K. & Janse Van Rensburg, R. W. 1986 Structure formation in bidisperse sedimentation. J. Fluid Mech. 166, 379407.Google Scholar
Batchelor, G. K. & Wen, C. S. 1982 Sedimentation in a dilute polydisperse system of interacting spheres. Part 2. Numerical results. J. Fluid Mech. 124, 495528.Google Scholar
Beenakker, C. W. J. & Mazur, P. 1874 Diffusion of spheres in concentrated suspension II. Physica 126A, 349370.Google Scholar
Brady, J. F. & Bossis, G. 1985 The rheology of concentrated suspensions of spheres in simple shear flow by numerical simulation. J. Fluid Mech. 155, 105129.Google Scholar
Brady, J. F. & Bossis, G. 1988 Stokesian dynamics Ann. Rev. Fluid Mech. 20. 111157.Google Scholar
Brady, J. F., Phillips, R. J., Lester, J. C. & Bossis, G. 1988 Dynamic simulation of hydrodynamically interacting suspensions. J. Fluid Mech. 195, 257280.Google Scholar
Bruneau, D., Anthore, R., Feuillebois, F., Auvray, X. & Petipas, C. 1990 Measurement of the average velocity of sedimentation in a dilute polydisperse suspension of spheres. J. Fluid Mech. 21, 577596.Google Scholar
Buscall, R., Goodwin, J. W., Ottewill, R. H. & Tadros, T. F. 1982 The settling of particles through Newtonian and non-Newtonian media. J. Coll Old Interface. Sci. 85, 7886.Google Scholar
Cox, R. G. 1990 Instability of sedimenting bidisperse suspensions. Intl J. Multiphase Flow. 16, 617638.Google Scholar
Davis, R. H. & Acrivos, A. 1985 Sedimentation of noncolloidal particles at low Reynolds number. Ann. Rev. Fluid. Mech. 17, 91118.Google Scholar
Davis, R. H. & Birdsell, K. H. 1988 Hindered settling of semidilute monodisperse and polydisperse suspensions. AIChE J. 34, 123129.Google Scholar
Fessas, Y. P. & Weiland, R. H. 1981 Convective solids settling by a buoyant solid phase. AIChE J. 27, 588592.Google Scholar
Fessas, Y. P. & Weiland, R. H. 1984 The settling of suspensions promoted by rigid buoyant particles. Intl J. Multiphase Flow 10, 485507.Google Scholar
Garside, J. & Al-Dibouni, M. R. 1977 Velocity-voidage relationships for fluidization and sedimentation in solid—liquid systems. Ind. Engng Chem., Proc. Des. Dev. 16, 206214.Google Scholar
Hasimoto, H. 1959 On the periodic fundamental solutions of the Stokes equations and their application to viscous flow past a cubic array of spheres. J. Fluid Mech. 5. 317328.Google Scholar
Kim, S. 1987 Stokes flow past three spheres: An analytical solution. Phys. Fluids 30, 23092314.Google Scholar
Kynch, G. J. 1952 A theory of sedimentation. Trans. Faraday Soc. 48, 166176.Google Scholar
Ladd, A. J. C. 1990 Hydrodynamic transport coefficients of random dispersions of hard spheres. J. Chem. Phys. 93, 34843494.Google Scholar
Phillips, R. J., Brady, J. F. & Bossis, G. 1988 Hydrodynamic transport properties of hard-sphere dispersions. I. Suspension of freely mobile particles. Phys. Fluids 31. 34623472 (referred to herein as PBB).Google Scholar
Thiokas, J. 1984 The instability of bidisperse suspensions. M.S. thesis, University of Illinois.
Thiokas, J. 1986 The stability of multiphase suspensions. Ph.D. thesis, University of Illinois.
Weiland, R. H., Fessas, Y. P. & Ramarao, B. V. 1984 On instabilities arising during sedimentation of two-component mixtures of solids. J. Fluid Mech. 142, 383389.Google Scholar
Whitmore, R. L. 1955 The sedimentation of suspensions of spheres. Brit. J. Appl. Phys. 6, 239245.Google Scholar
Zick, A. & Homsy, G. M. 1982 Stokes flow through periodic arrays. J. Fluid Mech. 115, 1326.Google Scholar