Vibration characteristics of the flexible rotor system of a centrifugal pump with the shaft misalignment and impeller unbalance

This paper proposes a dynamic model of the flexible rotor system in a centrifugal pump with the fluid excitations to investigate the vibrations caused by typical shafting faults including the shaft misalignment and impeller unbalance. The elastic deformation of the shaft and the time-varying excitations of the support bearings are considered. The effects of the shaft misalignment and impeller unbalance on the time- and frequency-domain vibrations of the system are discussed. Note that the shafting faults not only increase the amplitude of the system vibration, but also change the spectral components of the frequency-domain vibrations of the system. The shaft misalignment introduces an additional peak at the second harmonic of the system's rotating frequency. The impeller unbalance introduces some additional peaks at the second and third harmonics, respectively, in the system's rotating frequency. This research may offer some significant values for enhancing the operational reliability of centrifugal pump systems.