Axial dispersion of the continuous phase was investigated for single phase flow and dual phase flow in a lab size Rotating Disk Contactor (RDC) column. The column diameter was 100 mm. The inner diameter of the stator rings was 70 mm. The rotor disc diameter was 60 mm and the diameter of the rotor axis was 35 mm. Disc and stator ring distance was 36 mm. The design of the column except the disc and stator ring distance is based on the Misek design recommendations.

Residence time distribution was determined with the tracer NaCl by detecting the conductivity on two points along the extraction column. Flow rate of both phases and the rotor revolution were varied. The conductivity probes were installed in a distance of 1118 mm. Axial dispersion was determined for open-open boundary and expressed in terms of the dispersion number.

Based on these experimental results the flow pattern of the investigated RDC was then modelled by CFD-simulation with FluentŪ. For that purpose, different mesh-geometries and turbulence models were investigated. This was followed by the validation of single phase flow in 2D-axisymmetric and 3D applications with a simulation area up to 10⁶ cells.

Results:

The realizable k-ε model matches most favourably with experimentally obtained data. 2D-axisymmetric configuration sufficed simulation of the complex flow pattern in the RDC without notable loss of accuracy.

The calculation of the axial dispersion number of the continuous phase E_ax,c was carried out by applying the Discrete Phase Model on the simulated flow field. Subsequent comparison of simulation results with experimentally obtained data showed an acceptable correlation.