Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.
An estimation of increasing the average volume of
sedimentation velocity of fine particles in bidisperse suspension
due to their capturing in the circulation zone formed in the
laminar flow of incompressible viscous fluid around the
spherical coarse particle is proposed. The estimation is
important for an explanation of the non-monotonic shape of the
separation curve observed for hydrocyclones. The average
volume sedimentation velocity is evaluated on the basis of a
cellular model. The characteristic dimensions of the circulation
zone are obtained on the basis of a numerical solution of
Navier-Stokes equations. Furthermore, these calculations are
used for modelling the fast sedimentation of fine particles
during their co-sedimentation in bidisperse suspension. It was
found that the acceleration of sedimentation of fine particles is
determined by the concentration of coarse particles in
bidisperse suspension, and the sedimentation velocity of fine
fraction is proportional to the square of the coarse and fine
particle diameter ratio. The limitations of the proposed model
are ascertained.
