Numerical and Experimental Investigations of the Cavitating Flow in a Centrifugal Pump Impeller

This paper presents numerical simulations and experimental investigations of the cavitating flow through a centrifugal pump impeller of low specific speed. The experimental research was carried out at the Pfleiderer-Institute of the Technical University of Braunschweig, while the numerical simulations were performed at the Institute for Hydraulic Machinery and Plants at the Technical University of Munich (LHM). The cavitation model used is based on bubble dynamics and is able to describe the complicated and transient growth and collapse of the cavitation bubbles. The model has been implemented in the 3D CFD-code CNS3D developed at the LHM. The CNS3D-code has been applied to simulate the cavitating flow through a centrifugal pump impeller. The computed pump head, incipient NPSH and three-percent head drop are compared to the experimental data. Also the pressure distributions measured on the blades are compared with the computed ones. Finally, the numerically investigated void fraction distributions are shown in comparison with pictures of the cavitation zones on the blade.