Hydraulic Optimization and Loss Analyses of a Low Specific-Speed Centrifugal Pump With Variable-Thickness Blades

This paper investigates the hydraulic and dynamic performance of a low specific-speed centrifugal pump with CFD simulation. Three different impellers are designed with different thickness distributions along the same mean line of the blades. The entropy production is introduced to study the energy losses in the three models and the energy loss distributions of the whole flow passages are fully revealed. The simplified energy loss equation is carefully validated by comparing the thermodynamic efficiency to the traditional hydraulic efficiency, and the errors between them can be considered acceptable. The circumferential Euler head distribution out of the impeller is used to predict the uniformity of the flow into the volute. To obtain the transient flow characteristics, the sliding mesh technique and the unsteady CFD simulation are applied and the pressure pulsations in the volute are well captured. The head fluctuation intensities of the three models are quantitatively compared under constant flow rate. The results show that the thickness distribution can affect the hydraulic performance to a large extent, and it can strongly affect the pressure pulsation in the volute.