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A hydrofoil blade design (HBD) is proposed to suppress the unsteady pressure pulsations in a centrifugal pump. Numerical simulation is carried out using the SST k‐ω model to obtain the unsteady flow field in the pump both with HBD and the conventional blade design (CBD). The pressure pulsations with the two types of blade profiles are compared at the nominal flow rate, whereas the jet‐wake flow patterns and vortex structures are analyzed to clarify the effect of the HBD on the flow field. The pressure pulsation amplitudes at the blade frequency (fBPF) are significantly reduced with the HBD, especially near the volute tongue, with a reduction of 72%. It is evident that HBD can effectively suppress the pressure pulsation. It is for these reasons that the relative velocities in the jet region at the impeller outlet are reduced, and the velocity gradients between the pressure and suction side are decreased, which contributes to improving the flow uniformity at the impeller outlet. Besides, the vorticities at the impeller outlet are reduced, and the high energy vortices shedding from the blade trailing edge are restrained. The combined effects of the uniform flow field and low vorticities contribute to the reduction of pressure amplitude with the HBD. The findings would serve as a reference for the pump designs with low noise and vibration.

Rotating stall contributes to global oscillation vibration problems, accompanied by noise and possible turbomachinery damage. This study with special emphasis on the vaned diffuser investigates the unsteady pressure interaction with the stall within the pump. A low specific speed centrifugal pump (n s = 69), fitted with a vaned diffuser is modeled and studied. The model pump performance curve shows the characteristic positive slope at 30% of the best efficiency point flow rate; 1.0 Φ Ν which is attributed to the stall phenomena.A finite volume method is employed with unsteady computations initialized utilizing shear stress transport k-ω before proceeding with DDES. Pressure fluctuation and velocity magnitude normalized values are used to investigate the evolution of stall cell generation. The root mean square (RMS) values and normalized pressure (Cp) values are elicited to gain insight into pressure pulsation within the flow domain. The distinguished "starfish" shape is observed for monitor points md1 to md20, with the RMS trend decreasing with increasing flow rate from the pump shut off. Although in the vaned diffuser flow channel, an increase in pressure fluctuation along the flow channel toward the trailing edge is observed, the vaned diffuser channel shows a similar trend. The stall cell propagates at a speed of Ω RS = 0.078 at 0.2 Φ Ν , while at 0.1 Φ Ν propagates at a speed of Ω RS = 0.087; the stall speed tends to increase approaching pump shut off. Three distinguishable stall channels are observed from the flow structure for a five vaned diffuser; entering the stall, stalled, and stall recovery stages, within the flow channels.

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