Using CFD to Describe the Hydrodynamics of Internal Air-lift Reactors

The hydrodynamics of three configurations of internal airlift reactors, two with riser diameters of 0.1 m and one with a riser diameter of 0.24 m, operating with air–water system, have been experimentally investigated for a range of superficial gas velocities. The experimental results are compared with a model using computational fluid dynamics (CFD) with Eulerian descriptions of the gas and liquid phases. Interactions between the bubbles and the liquid are taken into account by means of a momentum exchange, or drag coefficient based on a literature correlation. The turbulence in the liquid phase is described using the k-(epsilon) model. The CFD model shows good agreement with the measured data on gas holdup, liquid velocity in the downcomer and in the riser for all three configurations. The developed CFD model has the potential of being applied as a tool for scaling up.