<p>In this work, the size effects on the sedimentation behaviors of two non-identical particles are investigated through the lattice Boltzmann method (LBM). The method is first validated by simulating the settling process of two identical-size particles, which correspond well with previous results. Then the hydrodynamic behaviors of double non-identical-size particles settling in an infinite-long narrow channel are investigated, in which the larger particle is initially placed above the smaller one. Different sedimentation behaviors are observed with different diameter ratios in the present work. In the first Draft-Kiss-Tumble (DKT) cycle, it is observed that the time durations of both drafting state and kissing state are shortened by the increase of the diameter ratio γ. Considering a longer sedimentation time, three different settling behaviors are observed with different diameter ratios, which can be summarized as: (1). Repeated DKT cycle (1.0≤γ≤1.13); (2). Repeated DT-DKT after the first DKT cycle (1.14≤γ≤1.22); (3). Separation after the first DKT cycle (1.23≤γ). It should be noted that behavior (2) is first defined in this work, which helps explain the divergence in the threshold diameter ratios of the recurrence of DKT cycles proposed in the previous literatures. In addition, the frequency of the repeated cycles experiences instant decrease and increase against the diameter ratio near the transition from behavior (1) to behavior (2), while an instant decrease is also observed near the threshold diameter ratio between behavior (2) and behavior (3).</p>

An LBM Study of the Sedimentation Behaviors of Double Particles With Non-Identical Sizes

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

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