STP1077: Cavitation Monitoring of Hydroturbines with RMS Acoustic Emission Measurement

    Derakhshan, O
    engineers, Tennessee Technological UniversityEngineering Laboratory, Tennessee Valley Authority, CookevilleNorris, TNTN

    Houghton, JR
    engineers, Tennessee Technological UniversityEngineering Laboratory, Tennessee Valley Authority, CookevilleNorris, TNTN

    Jones, RK
    engineers, Tennessee Technological UniversityEngineering Laboratory, Tennessee Valley Authority, CookevilleNorris, TNTN

    March, PA
    engineers, Tennessee Technological UniversityEngineering Laboratory, Tennessee Valley Authority, CookevilleNorris, TNTN

    Pages: 11    Published: Jan 1991


    Abstract

    Acoustic Emission measurements are shown to be a reliable indicator of cavitation pressure pulses. The method of display is the root mean square, RMS, of the AE signal integrated over 1 second that is proportional to the average cavitation energy. An inexpensive AE transducer, amplifier, filter, and RMS circuit is described with a gain of 22 dB and a frequency range of 10 kHz to 1.25 MHz. Data from two laboratory controlled cavitation experiments is presented. The system is tested on two TVA hydroturbines. Kaplan-type and Francis-type turbines had a similar shaped increased RMS AE curve with wicket gate opening but the numerical maximum values are different in each hydroturbine installation. A real-time continuous RMS AE monitor is recommended on each hydroturbine for the evaluation and control of cavitation erosion.

    Keywords:

    Cavitation, Acoustic Emission (AE), Energy, Root Mean Square (RMS)


    Paper ID: STP19102S

    Committee/Subcommittee: E07.04

    DOI: 10.1520/STP19102S


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