Cavitation diagnosis of hydraulic turbine runner blade based on cavitation intensity
Cavitation of hydropower generating units erodes over-flow components,aggravates vibration,reduces units efficien-cy and affects the stability of units.Cavitation diagnosis is important to the safety operation of the units.Cavitation radiation energy signal is a broadband signal,but the conventional method only monitors a certain characteristic frequency or frequency band,which is difficult to achieve accurate cavitation monitoring,so we propose to monitor the cavitation of turbine rotor blades based on cavi-tation intensity.Based on the monitoring principle,the impact of cavitation on the energy distribution characteristics in the fre-quency domain is compared and analyzed,and the degree of cavitation intensity is proposed to characterize the strength of cavitati-on;then a mathematical model is proposed to determine the occurrence of cavitation based on the cavitation mechanism and hy-draulic turbine test data.Finally,the cavitation bench test of the hydraulic turbine was carried out to verify the effectiveness of the proposed monitoring index.The results show that cavitation will lead to an increase in the proportion of high frequency band com-ponents,and the"cavitation intensity"index constructed based on the ratio of high and low frequency energy areas can effectively determine the occurrence and strength of cavitation,and the accuracy of the bench test was100%.The results can provide a theo-retical basis for the detection of cavitation in underwater mechanisms.
hydropower generating unitshydraulic turbinesrunner bladecavitation determinationcavitation intensitycav-itation detection system
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