NUMERICAL SIMULATION OF THE TRANSIENT THREE-DIMENSIONAL GAS-LIQUID FLOW IN A CYLINDRICAL BUBBLE COLUMN

In this paper the transient three-dimensional flow developing in a cylindrical laboratory bubble column is addressed from a numerical point of view. The simulation scheme combines a Large Eddy Simulation (LES) for describing the liquid phase and a Lagragian approach for the gas (discrete) phase. The bubble equation of motion considers all the relevant forces, i.e., buoyancy, pressure, drag, added mass and transverse lift. From the calculations, the transverse lift in combination with the drag is identified as the main mechanism allowing the bubbles to spread over the column cross-section. The liquid and gas velocity profiles obtained are compared with the experimental data and kappa-epsilon results presented in Lain et al. (2001). As a matter of fact, the dynamic structure of the liquid flow induced by the rising bubbles is well reproduced and also good quantitative results for all measured variables of both phases, gas and liquid, are obtained.