Unsteady Velocity PIV Measurements and 3D Numerical Calculation Comparisons Inside the Impeller of a Radial Pump Model

PIV measurements were performed at mid hub to shroud section inside the impeller of a vaned diffuser pump model working with air. Several previous papers have already presented part of impeller flow characteristics mainly for vaneless diffuser and near nominal mass flow rate. This paper concerns the pump configuration where the diffuser blades interacted with the impeller flow. Each PIV measuring plane was related to one particular impeller blade to blade channel and analyzed according to different relative positions of the vaned diffuser. A fully unsteady calculation of the whole pump has been performed and comparisons between numerical and experimental results are presented and discussed for four different mass flow rates. The present analysis is restricted to the outlet section of the impeller blade to blade passage for one particular impeller blade position relative to the diffuser.