The PIV Measurements on the Flow Fields in an Unshrouded Centrifugal Pump

PIV was applied to the measurements of flow field in an unshrouded centrifugal pump impeller. Three windows were selected for the measurements. Three operation points of the pump were taken during the measuring. The ratios (Q/QBEP) of the flow rate for measuring are 0.6, 1.0, and 1.4, respectively. The velocity distributions in blade-to-blade passages obtained at different windows give the evidence that the velocity distributions are asymmetric even under the design operation point. A lower velocity zone existed at middle of blade-to-blades passages near the pressure-side of the blade.