Measurement of Axial-flow Compressor Operation Using an AE Sensor

Abstract

In the gas turbine system, which is exposed to frequent variation of load, compressor operation needs to be monitored constantly. For the monitoring device, hot-wire probes or accelerometers are generally used, but those devices need measurement holes. Introducing the simple device that does not need measurement holes have been desired. So the adaptability of Acoustic Emission (AE) sensor to compressor monitoring was verified. AE sensor was installed on the surface of the casing of axial-flow compressor that was operated steadily. AE signal was acquired on 6 different operating points of the compressor. Frequency analysis of those AE signals showed that the lower flow coefficient φ became, the higher the voltage of AE signal became, in the band from 35kHz to 42kHz. So the AE signals were filtered from 35kHz to 42kHz and then root mean square (RMS) of the AE signals was calculated. As a result, the lower flow coefficient φ became, the higher RMS became. So the possibility of applying AE sensor to the compressor operation monitoring was suggested.