Experiments in bubble columns for CFD model validation

Bubble columns are widely used in industrial application and are an actual object of research. The performance of a bubble column strongly depends on the characteristic of the flow, which can be modeled with the methods of computational fluid dynamics (CFD). A widely used CFD approach for modeling such dispersed multiphase flows is the Eulerian two-fluid approach.
With the Eulerian two-fluid approach large apparatuses can be simulated in a short time; however, the interaction between the dispersed and the continuous phases has to be modelled with closure models. The closure models refer to different forces and effects, such as drag, lift, virtual mass, turbulent dispersion, coalescence & break up and bubble induced turbulence. The usage of a proper set of closure models is an actual discussion in the scientific community (Rzehak & Krepper 2013) and proper experiments are needed for model validation.
To validate the above mentioned effects that the closure models have to cover, a wide range of experiments are needed. In addition, such experiments should allow measuring the relevant data for a model validation. The must have relevant data are the bubble size distribution, the local void fraction and the liquid velocity at different positions.
In the present study an airlift air-water bubble column, a partially aerated air-water bubble column and an air-NaCl solution bubble column is investigated. The bubble size distribution, the local void fraction and the liquid velocity will be shown at different positions in the bubble column. In addition, a comparison of the experimental results with simulations using an Euler-Euler unsteady Reynolds averaged Navier Stokes equation approach as described in Ziegenhein et al. 2015 is given.