Numerical investigation of particle cloud sedimentation in power-law shear-thinning fluids for moderate Reynolds number

Abstract

A series of numerical simulations are performed for the sedimentation process of a particle cloud in shear-thinning fluids using lattice Boltzmann and discrete element methods. The initial particle concentration, , and the power-law index of the fluid, n, and Reynolds number, , are varied in these simulations. For , the particle cloud size grows in the longitudinal direction as the cloud settles, leading to reduced particle concentration and a quasi-steady settling velocity, . The velocity ratio, , where is the corresponding single-particle terminal velocity, is found to decrease with both n and . This velocity ratio is only weakly dependent on the initial concentration () due to particle dispersion. For , the cloud loses its initial shape and disintegrates while settling, with particles escaping from the cloud due to differential particle settling velocities.