Lattice Boltzmann-immersed boundary method simulation of liquid bridge between two moving particles

Accurate modeling of liquid bridge dynamics between moving particles is critical for understanding particle agglomeration, coating, and flotation processes; however, resolving the coupled fluid–particle interactions at realistic scales remains challenging. In this work, we develop a coupled lattice Boltzmann-immersed boundary method (LBM-IBM) framework to investigate the transient formation, evolution, and rupture of liquid bridges between two moving particles. The effects of droplet diameter, Reynolds number, Bond number, particles' diameter ratio, and eccentricity ratio are systematically analyzed. The study identifies distinct stages of particle motion: an initial stage dominated by hydrodynamic forces, a collision-dominated stage, and a final stage governed by gravity and capillary forces, with further sub-stages arising from capillary effects. A liquid ring forms for sufficiently large droplets and its size increases with rising eccentricity. The rupture of the liquid bridge is delayed when viscosity, gravitational effects, or particle asymmetry increase. Occasional cavitation bubble formation is also observed. This work demonstrates that the LBM–IBM coupling enables accurate resolution of microscale fluid–particle interactions and can provide quantitative insights relevant to spray coating, dust removal, and fine particle flotation, addressing a critical gap in current multiphase modeling approaches.