Experimental Measurement of Cavitation-Induced Vibration Characteristics in a Multi-Stage Centrifugal Pump

摘要

To examine the effect of cavitation on the vibration of a multi-stage pump, a five-stage diffuser centrifugal pump was selected to test the vibration characteristics under non-cavitation and cavitation conditions. Vibrations were monitored at six points (V1-V6). Results show that when cavitation occurs, the vibration characteristic frequencies of the six measuring points obviously increase, for 1.0Q(d) (the design flow rate). The gap in the vibration velocity amplitude between the higher axial frequency harmonics and the main frequency becomes smaller, and the cavitation-induced vibration excitation is very obvious in all directions. When the flow rate is 0.8Q(d), peak values at the main vibration frequencies of the measuring points V1, V2 and V4 increase compared to those at 1.0Q(d). Vibration intensities when the flow rate is 1.2Q(d) are larger than at 0.8Qd, and vibration intensities at 1.0Q(d) are the lowest of the three. At 0.8Q(d) and 1.2Q(d), the maximum vibration intensities of the pump are 2.01 mm/s and 2.47 mm/s respectively, which is an increase of 87.85% and 111.11%, respectively.