Fluid–structure interaction on the rotor-dynamic characteristics of a low-specific-speed centrifugal pump considering multi-scale fluid excitation effects

Centrifugal pump rotor system is a complex vibration system due to the unsteady multi-scale fluid–solid interactions (FSIs). In order to explore the coupling vibration of the rotor system between the multi-scale fluid domain and different flow conditions, the bidirectional fluid–solid interaction (BFSI) was carried out, and the numerical and experimental results of the centrifugal pump performance were compared. The transient forces of the impeller and vibration characteristics of rotor system considering BFSI for different flow rates, wear-ring clearances, and axial movements were also studied in detail. The results show that the maximum errors of head and efficiency between the simulation and experiment are only 5.41% and 2.33%, respectively. The radial force of impeller is smallest at 1.0Qd and the axial force decreases with the increase in flow rate. The average deformation and stress of the rotor system reaches to 0.35 mm and 70.7 MPa, respectively, when the axial movement increases to +1.5 mm. The vibration acceleration on the blades increases gradually from the root to the top, and the vibration acceleration on the shaft is greater than that at the impeller.