Numerical simulation of single gas bubbles under shear flow conditions

Disperse gas bubbles play an important role in many industrial applications. Knowing the rising velocity, the interfacial area, or the critical size for break-up or coalescence in different systems can be crucial for the process design. Usually the flow experienced by bubbles is not uniform but sheared. Under shear-flow conditions bubbles develop a lift force perpendicular to the flow direction. In the present work direct numerical simulations are applied to examine the dependency of the lift force on the shear rate for bubbles in pure liquids. A level-set based volume-tracking method is implemented into the CFD-code OpenFOAM, to follow the free interface of the gas bubble. Results show good agreement with available experimental results from single bubbles in a rotating chamber. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)