SYMPOSIA PAPER Published: 01 January 1991

Cavitation Monitoring of Hydroturbines with RMS Acoustic Emission Measurement


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.

Author Information

Derakhshan, O
Houghton, JR
Jones, RK
March, PA
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Developed by Committee: E07
Pages: 305–315
DOI: 10.1520/STP19102S
ISBN-EB: 978-0-8031-5160-4
ISBN-13: 978-0-8031-1389-3