Unsteady pressure-pulsation-induced severe vibration and high alternating stress can cause some unexpected results, including impeller crack and structural damage of the entire pumping system. In the present paper, a review on pressure pulsations in pumps is carried out based on the published studies. A comprehensive view on pressure pulsations from several aspects is discussed in detail. The contents of the studies include the mechanism of rotor–stator interaction; a prediction model and experimental and numerical investigations of pressure pulsations; unsteady rotating-stall-induced pressure pulsations at off-design flow rates; the relationship between pressure pulsation and the internal flow structure and cavitation; and the reduction in pressure pulsation caused by some effective approaches. It is concluded that unsteady pressure pulsation in pumps is closely associated with complex flow structures, for instance flow separation, cavitation, and rotating stall. The rotor–stator interaction mainly dominates pressure pulsation characterized by the discrete components in pressure spectrum. To reduce pressure pulsation, some effective approaches are proposed, such as increasing the rotor–stator gap, staggered blade, and blade modification. Finally, several suggestions for future works are given and discussed considering the current research. The review contributes to better understanding of pressure pulsations in centrifugal pumps, and may also benefit engineers in controlling pressure pulsations in some fields, such as pumps in nuclear reactor.

For the centrifugal pump, the rotor–stator interaction (RSI) induces high-energy pressure pulsation, which directly affects the stability of systems and equipment. Therefore, this work proposes a new staggered impeller structure to suppress high-energy pressure pulsation in centrifugal pumps. The original impeller blade is divided into two layers and is staggered at 10°, 20° and 30° to form a staggered impeller. The dynamic pressure pulsation characteristics of both the original impeller and the staggered impeller are predicted using large eddy simulation (LES). The results indicate that the uniform staggered arrangement of blades can significantly reduce the pressure pulsation energy in the pump by 54.69% under the design conditions, while also achieving the best performance. Even under off-design conditions, the pressure pulsation energy can still be effectively suppressed by the staggered blades. The study of the time–frequency domain of the monitoring points near the tongue found that the phase difference in the pressure fluctuation caused by the RSI between the staggered impeller and the tongue prevents the superposition of pressure pulsation energy and efficiently suppresses it in the pump. The results can provide a reference for optimizing low-vibration-noise pump impellers in engineering applications.

The nuclear reactor coolant pump (RCP) is the core piece of equipment of a nuclear power plant (NPP). The energy performance and internal flow characteristics of RCPs are revealed by effective measurement methods, which are helpful to understand the flow mechanism of RCPs. The present work is intended to conduct an integrated study based on the energy performance test and Particle Image Velocimetry (PIV) flow-field non-contact measurement of the RCP. In addition, the prediction results of different turbulence models are compared with experimental results in detail. Through energy performance measurement and numerical calculation analysis, it can be found that various turbulence models have the ability to predict the performance of RCPs in engineering applications. At 0.8~1.2 Φ_d operating conditions, the maximum error is less than 10% and the minimum error is less than 0.1% by analyzing the energy performance of numerical calculations and experimental results. The PIV results show that the velocity of the discharge nozzle varies greatly from right (outlet of diffuser channel 2) to left (outlet of diffuser channel 12) due to different flow structures. Through the qualitative and quantitative comparison of the internal flow field, it can be concluded that, except for the low flow rate, compared with other computational models, the Realizable k-ε model can better predict the internal flow field of an RCP. The reasons for the experimental error and numerical calculation error are analyzed in detail, and the results can provide a reference for forecasting an RCP internal flow field with a special and complex structure.

To reveal the contribution of flow-induced noise sources and their spatial distribution characteristics in a centrifugal pump, the broadband noise source model and the acoustic analogy method coupled with large eddy simulation and finite element method are applied to investigate the dipole source and quadrupole source under the nominal condition. The validity of the numerical method is verified through measurements of flow-induced noise. Results demonstrate that the sound power of the dipole source is significantly higher than that of the quadrupole source caused by turbulence and vortices, with the main noise source regions identified as the blade suction side and the spiral section of volute. Flow-induced noise in the frequency domain exhibits a combination of broadband components and discrete components, with the discrete components being the blade passing frequency (fBPF) and its harmonics. The blade dipole source exhibits dense discrete spectrum, with discrete components also including subharmonics of the fBPF. At the inlet and outlet, the contribution of blade dipole to low-frequency noise is significantly greater than the volute dipole. As the frequency increases, the contribution of the volute dipole gradually rises. When the frequency exceeds 20 times the fBPF, the dominant noise component shifts to the volute dipole, a phenomenon that is more pronounced at the outlet. The intensity of noise inside the volute is lower than that at the pump inlet and outlet, with the blade dipole as the dominant source, which exhibits a sound pressure level at the fBPF that even surpasses the total noise.

High−energy pressure pulsation induced by rotor−stator interaction (RSI) is the primary source of flow−induced vibration noise in the pump, affecting the pump’s stability and system operation. In order to find an effective method to suppress the pressure pulsation in the pump caused by RSI, a new staggered impeller is proposed in this paper, which can significantly suppress the pressure pulsation energy. The unsteady pressure pulsation characteristic of the original impeller and the staggered impeller scheme are measured and analyzed under different working flow conditions. The results show that although the hydraulic performance of the model pump decreases to a certain extent when the staggered impeller is used, the pressure pulsation energy in the pump decreases significantly. Under 0.8Q_N–1.2Q_N working flow conditions, the energy suppression effect of the blade passing frequency (f_bpf) amplitude is higher than 80% with the staggered impeller scheme. The Root Mean Square (RMS) values for distribution of pressure pulsation in different frequency bands varies greatly, and the pressure pulsation energy near the tongue is prominent. On a broader frequency band (0–6 f_bpf), the pressure pulsation energy of the staggered impeller scheme is smaller than that of the original impeller scheme. With the expansion of the frequency band, the pressure pulsation energy decreased steadily, with a minimum decrease of 37.33%.