Investigation of the flow field in a centrifugal rotor through particle image velocimetry

Abstract

This work aims to investigate the flow field in a centrifugal rotor using two-dimensional Particle Image Velocimetry (PIV). The flow is analyzed at different planes for different rotating speeds and flow rate operations. The assumed rotor is a prototype with equal inlet and outlet blade angles and is built to have a quasi-2D geometry. The PIV measurements were performed using the phase-locking technique, in which 500 samples were obtained from each experiment. Results for pressure, velocity, Reynolds shear stress, and turbulence intensity show that the flow in the centrifugal rotor behaves according to kinematic similarity, even at part-load operation. Moreover, it was observed that the flow could be considered periodic in the rotor channels for the best efficiency point flow rate and at part-load conditions. From the analysis conducted at different planes, differences could be observed in the flow near the hub or shroud for flow rates above 0.75∙QBEP. In general, the velocity magnitude is higher near the hub than near the shroud, while turbulence intensities tend to be higher near the shroud than near the hub. This difference can be attributed to the change in the flow direction from the development pipe to the rotor channels.