Investigation Of Fault Diagnosis Of Cavitation In Variable Speed Centrifugal Pump Using Pressure Fluctuation Method

Centrifugal pump as a kind of general fluid machinery equipment plays animportant role in electirc power, petrochemical process, agricultural drainage andirrigation and textile department etc. Cavitation is a common fault of pump. Theoccurrence and development of cavitation may change velocity distribution in thechannel, which may cause the decrease of flow rate and therefore efficiency, anddamage flow passage components like impeller.Fault diagnosis, currently as an independent cross synthetic information processtechnique, one of basic measures to maintain the equipment running safely. It canpredict the early failure of the equipment, make judgment to the cause of failure, andavoid or decrease accident. It is significant to search for method of cavitationdiagnosis and recognition, to exclude cavitation fault rapidly and accurately, toprevent cavitation damage, to improve pump efficiency and to prolong the servicelife.The paper analyzed cavitation signals under various flow cases, and proformedfault diagnosis to cavitation fault of centrifugal pump. For more accurateexperimental data, frequency converter was used to adjust flow and turbine flowmeter was used to mesure flow rate. According to the characteristic of inlet pressurefluctuation signals, cavitation fault diagnosis of centrifugal pump was studyed.Finally, the signals collected were analyzed and handled using different methods.From wavelet energy analysis, EMD energy entropy analysis, EMD energy withband energy values of HHT marginal spectrum respectively, the paper compared andhandled inlet pressure fluctuation signals, obtained the advantadge of each method,analyzed the methods which were suitable to which stage(s) of cavitation faultdiagnosis of centrifugal pump, and laid a solid foundation for the application of eachmothod.