Optimization of Rotor Geometry for a Type of Self-Suction Aerating Mechanical Flotation Cell

Abstract

The hydrodynamics generated by forward-rotor (F-rotor), radial-rotor (R-rotor), and backward-rotor (B-rotor) geometries in flotation cells are systematically investigated through particle image velocimetry (PIV) measurements and computational fluid dynamics (CFD) simulations. The experimental PIV data is used to validate the simulated results obtained by the multiple reference frames (MRF) method with standard κ–ε turbulent model. It is shown that the simulated flow field and local axial and radial velocities are in agreement with the measured PIV data. The flow field and turbulence distributions as well as circulation volume for F-rotor, R-rotor, and B-rotor geometries are predicted. The simulation results demonstrate that the change of lower blade angle has little effect on flow pattern and turbulence distributions outside the rotor-stator. However, B-rotor requires 2.4% and 3.3% lower power draw while yielding 3.8% and 7.2% larger circulation volume than F-rotor and R-rotor, respectively, under the same angular velocity, giving the B-rotor the highest pumping efficiency.