The monitoring of cavitation in centrifugal pumps based on the analysis of vibro-acoustic measurements

Cavitation in centrifugal pumps causes damages to pump components and produces high levels of vibration and noise, which not only reduces pump performance but also consumes additional energy. Unfortunately, many pumps operate under a certain degree of cavitation for a number of reasons such as varying operating conditions, inadequate installation and harsh environments. To evaluate the degree of cavitation online and to take necessary actions at an early stage, this research focuses on developing a cavitation measurement technique using non-intrusive vibro acoustic techniques. In this paper, conventional vibro-acoustics measurements are examined with different dimensionless parameters for characterizing the signals and hence for cavitation diagnosis. Conventional parameters such as peak factors and kurtosis from both the time domain and frequency domain have been evaluated to be inefficient for indicating cavitation in different stages. However, the spectral entropy has been found to be more accurate in presenting the cavitation. Especially, the spectral entropy from airborne acoustics can yield a better diagnostic result than the surface vibration.