Experimental analysis and computational modelling of gas-liquid stirred vessels

The aim of this work is to investigate the turbulent hydrodynamics of a gas-liquid stirred tank of standard geometry through experiments and simulations. The 2-D velocity fields are obtained by a two-phase PIV technique, consisting of a pulsed Nd:YAG laser, emitting light at 532 rim, and two cameras, each provided with a filter, that allow to discriminate between the light scattered by the fluorescent liquid seeding particles and that scattered by the bubbles. The experimental results obtained at different gas flow rates are presented, compared with single-phase data and discussed for gaining insight into the gas-liquid flows. They are also adopted for the quantitative evaluation of the results produced by CFD simulations based on a Two Fluid Model approach. The agreement between the experimental and the calculated mean velocity fields indicates that the selected CFD modelling is appropriate for the prediction of the mean hydrodynamic features of gas-liquid dispersions in stirred vessels.