Lattice Boltzmann simulation of particles inertial migration with slippery surface and moderate concentration in circular tube flow

Abstract

Hydrodynamic migration of spherical slippery particles suspended in a cylindrical channel flow is numerically studied in this paper. The effects of the particle concentration of particle ([Formula: see text], tube-to-particle diameter ratio ([Formula: see text] and Knudsen number (Kn), respectively, with ranges of [Formula: see text] and [Formula: see text] with the channel Reynolds number of [Formula: see text], are concerned in the simulations. The objective of this work is to explore the pipeline transportation of relatively large and moderately dense particles with slippery surface, for which the characteristics have not been comprehensively exhibited in the literature. Such particle-resolved suspension flow is solved by a three-dimensional lattice Boltzmann method, where a curved kinetic boundary condition is adopted to resolve the velocity slip phenomenon at the fluid-particle interface, and the particle-particle collision is performed by a repulsive force model. The results elucidate that the effect of particle focusing is less marked at intermediate concentrations. At larger [Formula: see text], some particles may migrate to the center of channel due to the aggravation of the mutual collision. The increase of Re contributes to the particle focusing at low [Formula: see text], but not for the case of higher [Formula: see text]. On the other hand, the [Formula: see text] generally has a negative effect on the inertial focusing. Furthermore, the migration velocity of particles reduces and the behavior of inertial focusing is enhanced simultaneously, with the increase of Kn.