Comparisons Between Numerical Calculations and Measurements in the Vaned Diffusor of SHF Impeller

Abstract

The paper presents analysis of the performance and the internal flow behaviour in the vaned diffusor of a radial flow pump using PIV (Particle Image Velocimetry) and pressure probe traverses. PIV measurements have already been performed at mid height inside one diffusor channel passage for a given speed of rotation and various mass flow rates. These results have been already presented in several previous communications. New experiments have been performed using a 3 holes pressure probe traverses from hub to shroud diffusor width at different radial locations between the two diffusor geometrical throats. Numerical simulations are also realized with the commercial codes Star CCM+ 7.02.011 and CFX. Frozen rotor and fully unsteady calculations of the whole pump have been performed. Comparisons between numerical results, previous experimental PIV results and new probe traverses one’s are presented and discussed for one mass flow rate. In this respect, a first attempt to take into account fluid leakages between the rotating and fixed part of the pump has been checked since it may affect the real flow structure inside the diffuser