Acoustic and Ion Sensing of Lean Blowout in an Aircraft Combustor Simulator Suraj Nair

This paper describes work to develop practical, fast diagnostic techniques that can be used to monitor the proximity of a combustor to blowout using measurements of the flame’s acoustic and ion signatures. A novel ignition system with ion sensing capability is used for blowout detection in conjunction with acoustic sensing. Data was acquired from a commercial single nozzle combustor fueled with Jet-A. As lean blowout is approached, short duration, localized extinction and re-ignition events were observed. Several signal processing schemes were developed to detect these blowout precursors, including signal thresholding and spectral analysis. The analyses revealed changes in the low frequency acoustic and ion spectra and increased presence of intermittent precursor events in both acoustic and ion data closer to blowout. I