A lattice Boltzmann method for simulating transport and agglomeration of resolved particles

The main purpose of this contribution is to present a lattice Boltzmann method for modelling the transport, collision and agglomeration of freely moving spherical particles and agglomerates. In order to take the hydrodynamic interaction between fluid and particles into account, the particle surface is fully resolved by the numerical grid using a curved no-slip boundary condition. In addition to various test cases with sedimenting single particles and particle pairs, a comparison with a finite element simulation is performed to evaluate the LBM-based treatment of flow-induced particle forces for gap widths smaller than the resolution limit of the fluid. Furthermore, the influence of viscous forces on the motion of approaching particles is analysed. As a final step, first results on the transient agglomeration inside a poly-sized particle cluster settling under gravity are presented for demonstrating the applicability of the code to more complex problems such as agglomeration in turbulent two-phase flows. The obtained agglomerate morphologies are characterised by various structural parameters such as a convex hull-based porosity and the radius of gyration. In the simulations, the observed particle Reynolds numbers are in the range 0.2, 84.8].