Experimental Investigation of Impeller Material on the Vibration Spectrum in a Centrifugal Pump

This study investigates the effect of impeller material on the vibration emission level from a centrifugal pump under various operating conditions, including normal operation, the onset of cavitation, and fully developed cavitation. Five different impeller materials—plastic, cast iron, brass, stainless steel, and aluminum—were experimentally tested. Cavitation was determined at the separation point on H-Q curve when the head dropped by 3% and by analyzing the vibration spectrum at a pump speed of 2850 rpm with varying suction pressures. The experimental setup included a centrifugal pump equipped with pressure transducers and a turbine flow meter to measure the suction pressure, outlet pressure and water volume flow rate. Vibration acceleration measurements were taken using an accelerometer with bandwidth of 20-20000 Hz, recorded via a data acquisition system using LabVIEW software. Results indicate that the plastic impeller generates the lowest vibration levels in both the normal and cavitation conditions. Furthermore, the vibration spectrum amplitude in the high-frequency range of the vibration spectrum varied significantly between different impeller materials during the normal pump operation. Cavitation can lead to an increase in the vibration amplitude in the high frequency range. This study provides quantitative insights into the vibration behavior of impeller material, suggesting plastic impellers as optimal for vibration reduction strategies.