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In this paper, the wake and potential flow effects of the rotor–stator interaction in a centrifugal pump with guide vanes are investigated from the view of the separation of turbulent and acoustic pressure fluctuations. The highest vibration levels in pumps are, in general, originated in the potential flow and wake effects. However, it is challenging to distinguish their effects on flow evolution. The pellicular mode decomposition method is applied to innovatively separate potential flow and wake disturbances in a centrifugal pump. By pellicular, we mean an infinitely thin layer of air located on the monitoring surface. The pellicular modes are a set of acoustic modes, with which a set of normalized orthogonal basis can be constructed. The impacts of potential flow and wake disturbances are visualized and evaluated quantitatively. The results show that only a very limited region is where the potential flow disturbance works. The higher the harmonics, the smaller the disturbance range. The wake disturbance is responsible for the modal pressure field. Modal pressure fields with low diametrical nodes decay more slowly than those with low harmonics. In addition, special attention is paid to the impact of the geometric asymmetry of the volute on the impeller force. The circular volute with a two-stage pressure drop improves the radial force of the impeller. More deep understandings on the mechanism of the rotor–stator interaction are reached by decoupling the potential flow and wake disturbances. This work serves as a guide for further research in fault diagnosis and vibration control of centrifugal pumps. [ABSTRACT FROM AUTHOR]

In this paper, the mechanism of the rotor–stator interaction in a centrifugal pump with guide vanes is studied numerically and theoretically. The dynamic mode decomposition method is employed to decouple and reconstruct the unsteady flow. A diametrical mode theory suitable for centrifugal pumps with guided vanes is proposed to determine the source of harmonics with higher amplitudes quickly. The results show that the dominant frequencies of the pressure pulsation in the volute and guide vanes are the blade passing frequency and its harmonic frequencies, and the corresponding flow structure is stable and has higher modal energy. The rotor–stator interaction effect around the impeller outlet is most pronounced. The potential flow effect works on the impeller and guide vanes but decays rapidly. The pressure pulsation caused by the wake effect propagates downstream and persists for long distances, which is the main reason for forming the modal pressure field in the volute. The modal reconstruction can reproduce the dynamic evolution process of the pressure field at the characteristic frequencies. The propagation characteristics of the modal pressure field in the volute can be accurately predicted by theoretical analysis. This research can provide an essential reference for fault diagnosis and vibration control of the centrifugal pump. [ABSTRACT FROM AUTHOR]