Assessment of statistical eddy-viscosity turbulence models for unsteady flow at part and overload operation of centrifugal pumps

The accuracy of linear eddy-viscosity URANS turbulence modelling is assessed for off-design operation of a single stage radial centrifugal pump. The open source software OpenFOAM is utilized. Hot wire probes have been utilized for measurement of spatially and temporally resolved validation data at the impeller discharge of the air-operated pump. The ensemble-averaged mean flow angle is in qualitatively good agreement to data for the entire operation range, while minor deviations occur close to the volute tongue due to impeller-volute interaction. Turbulence statistics from the simulation are compared to ensemble-averaged velocity RMS from measurements. RMS distribution is also qualitatively well reproduced for near-design and overload operation. A more pronounced RMS mis-prediction occurs in part load in the region of high impeller-volute tongue interaction and reveals limitations of turbulence modelling in highly unsteady flow regions of centrifugal pumps.