A study of an up- and a down-pumping wide-blade hydrofoil impeller: Part II. CFD analysis

Two different ways of using CFD to determine the flow field produced by the complex, wide-blade hydrofoil APV-B2 impeller are presented. The use of the "sliding mesh" approach was not successful and the reasons are discussed. Details of the numerical solution of the momentum transfer equations are described for the case of an axially-symmetrical jet model. The flow field for the single impeller pumping either upwards or downwards at 200 rpm was simulated using the structured Fluent code. Good agreement of CFD predictions with LDA velocity data was found, though the maximum local energy dissipation rate was 2 1/2 to 5 times lower than was estimated from the experiments. The power numbers predicted by CFD were slightly higher than those obtained experimentally. The flow fields for dual and triple impellers pumping upwards were also simulated and used to guide larger scale homogenisation experiments.