Investigation of hydrodynamic characteristics of a stationary Taylor bubble at different velocities of a downward liquid flow

The flow around a stationary gas Taylor bubble at downward flow velocities from 0.15 to 0.3 m/s in a vertical tube with a diameter of 20 mm was experimentally and numerically studied. Three-dimensional calculations were performed using the VOF (volume of fluid) method in the OpenFOAM package with application of the unsteady k–ω SST turbulence model. Hydrodynamic characteristics of the flow were experimentally studied using the electrodiffusion method. The effect of flow velocity on the change in the shape of the gas Taylor bubble nose was shown. The calculated and experimental data were compared and their good agreement was shown. The distribution of velocities in liquid and gas was studied as well as the distribution of the liquid film thickness around a gas Taylor bubble. It is shown that the wall shear stress in the liquid film around a gas Taylor bubble does not depend on the downward flow velocity.