Towards acoustic condition monitoring for detection and characterisation of laser-induced breakdown in a gas turbine laser ignition system

摘要

Acoustic detection and characterisation of laser-induced breakdown is an attractive proposition in laser ignition systems in which condition monitoring is necessary but where optical access for monitoring purposes is impractical. This paper presents a signal processing method basedon wavelet decomposition for the non-invasive detection of acoustic emissions resulting from laser-induced breakdown in an atmospheric pressure combustion test-rig, representative of a single combustion chamber in a sub-15 MW industrial gas turbine. The probability and consistency of laser-inducedbreakdown is determined from the acoustic signal and used to characterise the operating conditions and identify abrupt and incipient or slowly developing faults.