Application of Different Turbulence Models in Unsteady Flow Simulations of a Radial Diffuser Pump

Abstract

In this paper, the unsteady flow in a radial pump has been investigated numerically by utilizing different turbulence models at both design and off-design conditions. The numerical results are analyzed and compared on the pressure, relative velocity, and turbulence fields with experimental results from LDV and PIV. The analysis of the results shows that the turbulence model does not show significant influences on the pressure field. At the design condition (Q des), k-e predicts generally the best result on the relative velocity magnitude, slightly better than k-ω. However, k-ω has an overwhelming predominance on predicting the velocity vector directions and also on the turbulence kinetic energy. Furthermore, CFD can provide much better agreement to the measurements in the radial gap region than in the impeller region for all examined turbulence models. At off-design condition (0.5Q des), DES and SST turbulence models predict successfully a “two-channel” stall phenomenon in the impeller detected by the measurements, and other turbulence models failed to predict it.