Influence of the Stator/Rotor Interaction on Reverse Flow at Off Design Operation

A numerical analysis of the flow in a radial impeller will be presented with experimental validation. The low-pressure stage of a two-stage pump with a seven-blade runner and a vaned diffuser convoy will be under investigation. Initially, the vanes of the diffuser will be removed and only the impeller will be considered in order to emphasize the influence of the runner alone. Successively, the annular cascade of stationary vanes will be inserted. Experimental and numerical comparison will be made at the impeller inlet/outlet, focusing on the changing flow field at part load. The influence of the stator/rotor interactions on the onset of the reverse flow zones will be also analysed.