Eur. Phys. J. E 1, 105-114
Settling and fluidization of non Brownian hard spheres in a viscous liquid
P. Snabre1 - P. Mills2
1 Institut de Science et de Génie des Matériaux et
Procédés, B.P. 5, 66125 Font-Romeu, France
2 L.P.M.D.I, Université de Marne-la-Vallée, 5 boulevard Descartes,
Champs-sur-Marne, 77454 Marne-la-Vallée Cedex, France
snabre@imp-odeillo.fr
Received 22 February 1999 and Received in final form 14 June 1999
Abstract
A mean field approach is used to estimate the energy
dissipation during the homogeneous sedimentation or the particulate
fluidization of non Brownian hard spheres in a concentrated
suspension of infinite extent. Depending on inertial screening and the
range of the hydrodynamic interactions, the effective buoyancy force
is determined either from the average suspension density in a Stokes
flow or from the fluid density in the turbulent flow regime. An energy
balance then yields a settling or fluidization law depending on the
particle Reynolds number in reasonable agreement with the
Richardson and Zaki correlation and recent experimental results for
particle settling or fluidization. We further estimate the energy
dissipation in the turbulent boundary layers around the particles to
precise the Reynolds number dependence of the hindered settling
function in the intermediate flow regime.
PACS
47.55.Kf Multiplase and particle-laden flows
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47.90.+a Other topics in fluid dynamics
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83.10.Lk Multiplase flows
Copyright EDP Sciences, Società Italiana di Fisica, Springer-Verlag
