A numerical study of bubble and obstacle interactions considering liquid film drainage

Bubble-particle interactions play an important role in slurry bubble column design, since they influence, among others, mass transfer, mixing, and gas-solid contacting in slurry bubble columns. Therefore, we started a fundamental analysis by examining the interaction between a freely rising air bubble and a fixed cylindrical obstacle, employing high-resolution red three-dimensional (3D) Volume of Fluid (VOF) simulations. The simulation is compared to experimental findings for larger obstacles with good agreement, while no data is available for smaller obstacles. This work provides new insights regarding cylindrical with size down to 0.1 mm and fluid viscosities in the range 0.001Pa s–0.1Pa s. Thin-film drainage, pressure amplification, and bubble deformation are quantified while systematically varying geometric confinement and liquid viscosity for a hydrophobic obstacle surface. Simulation results show that increased confinement accelerates film thinning, amplifies lubrication pressure, and induces deformation that triggers early rupture. In contrast, minimal confinement results in capillary-dominated elongation and delayed drainage. Viscosity provides complementary control: higher viscosity suppresses deformation, stabilizes the thin film, and can delay or prevent rupture. A surface-area-based deformation index is introduced to quantify interfacial stretching, to connect confinement and viscous damping to interaction pathways.