Prediction of Bearing Fault Effect on the Hydraulic Performances of a Centrifugal Water Pump

Background: Bearing faults in centrifugal pumps usually result in periodically fluctuating torque, which leads to flow instabilities, pressure pulsation, excessive heating, and even pump failure. Purpose: This paper presents a theoretical approach for modeling and analyzing the impact of some typical bearing faults on the dynamic characteristics of a monoblock centrifugal pump. Method: The governing equations of the flow are solved by the method of characteristics, while the dynamic parameters of the asynchronous motor are predicted by adopting the d-q axes theory. Bearing faults are modeled as periodic square-wave pulses injected into the shaft of the pump. Result: The studies of the simulation results show that bearing fault has no significant impact on the pump H-Q curve but it has a large negative effect on the efficiency curve. Additionally, bearing failure in centrifugal pumps can induce head oscillation and flow rate fluctuation. Conclusion: In this work, the influence of bearing anomalies on the performance of centrifugal pumps was analyzed using a numerical method. The model analysis indicated that bearing faults in centrifugal pumps can lead to remarkable performance degradation, severe vibrations, and significant flow instabilities.