Simulation of particles settling in power-law fluids by combined lattice Boltzmann-smoothed profile methods

In the current study, the settling, interaction, drafting, kissing, and tumbling of two identical and non-identical circular particles were simulated in a two-dimensional box in shear-thinning, Newtonian, and shear-thickening fluids by using the combined lattice Boltzmann-smoothed profile methods. Furthermore, the drag coefficient of one particle settling for different power-law indexes and Archimedes numbers was calculated. Also, the effect of the diameter ratio of the two particle pairs was considered during settling. The developed method was validated by simulating the settling of one particle and two identical particles in a Newtonian fluid. To consider two non-identical particles, two cases were examined. In Case A, the larger particle was above the smaller one and in the Case B, the smaller particle was above the larger one. The results showed that the two non-identical particles were separated more easily than the identical ones. In the settling of two particles under the same Archimedes number, the drafting and kissing time considerably increased by changing the non-Newtonian fluid behavior from a shearthinning one to a shear-thickening one. Also, when the larger particle was above the smaller one, the time duration of the kissing stage increased with the decrease in the diameter ratio. (C) 2021 International Research and Training Centre on Erosion and Sedimentation/the World Association for Sedimentation and Erosion Research. Published by Elsevier B.V. All rights reserved.

Automated summary

This study simulated the settling process of two circular particles under different fluid conditions using lattice Boltzmann-smoothed profile methods, investigating the effects of different particle diameter ratios and non-Newtonian fluid behaviors. The results demonstrated that non-identical particles were more easily separated, and the behavior was altered under non-Newtonian fluid conditions.