Study On Ultrasonic Characteristic Of Early Cavitation Of Water Pump Based On Wavelet Analysis

Along with the start of south-to-north water diversion project, there will be a number of large and middle pumping stations to be in long-term service, of which security is more important. Therefore, security has been the index to value the large and middle pumping stations. There are many factors which can influence large and middle pumping stations' security, in which cavitation is one of the most important.From the 20 centuries, cavitation was always the important research problem in hydraulic mechanism science. To solve it, researchers worldwide have done large numbers of work. If cavitation can be detected in its early period during the pumping stations works, effective measures can be taken to reduce the cavitation breakage and prolong the life-span of pumping stations.This dissertation mostly researches the noisy and ultrasonic characteristic from theory and experimental ways when cavitation occurs early. The experiment includes the choice of experimental scheme, the collecting and processing of signal, etc. Through wiping off noise from signal, time domain and frequency domain analysis, wavelet analysis, wavelet package analysis, the law of cavitation noise intension and frequency distributing are found.