Study on the Vibration Characteristics of a Double-Suction Centrifugal Pump

Double-suction centrifugal pump (DSCP) exhibits distinctive characteristic of high head in large flow conditions, therefore, DSCP has been widely applied in drainage, irrigation, and other transportation projects. However, the vibration inside the pump due to unsteady flow structure and rotor–stator interaction is raising more and more attention, especially under the command of low vibration and noise environment. In this paper, a DSCP with terrible vibration problem is redesigned through changing the impeller diameter, blade number, and impeller arrangement to enhance the internal flow stability and reduce the impeller-tongue interfere intensity. The results show that, the redesign pump model #2 not only has better hydraulic performance, but also has excellent vibration behavior. Compare the vibration acceleration in vertical direction at outlet flange, and the frequency domain of two models are extracted to make further comparison. The primary blade passing frequency (BPF) in two models is 298 Hz, 347.7 Hz, respectively. The dominant frequencies in frequency domain are both positioned at BPF, and the amplitude in model #2 is much smaller than that in model #1. This phenomenon implies that the vibration in DSCP is induced mostly by the impeller rotation, and the vibration intensity in model #2 is largely reduced after redesign.