CHEMILUMINESCENCE’S EMISSIONS AND ACOUSTIC CORRELATION MEASUREMENTS OF STABLE TRANSITIONUNSTABLE SWIRL PROPANE/AIR FLAMES IN AN INDUSTRIAL COMBUSTOR

Salem A. Farhat; Mohamed S. Oun; Y. Zhang

doi:10.66411/jer.v9i9.163

Authors

Salem A. Farhat Mechanical Engineering Department, Faculty of Engineering, University of Al-Fateh, Tripoli – Libya Author
Mohamed S. Oun Mechanical Engineering Department, Faculty of Engineering, University of Al-Fateh, Tripoli – Libya Author
Y. Zhang School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester M60 1QD, UK Author

DOI:

https://doi.org/10.66411/jer.v9i9.163

Keywords:

Transition of stable to unstable combustion, Chemiluminescence emissions, Acoustic pressure

Abstract

Combustion instabilities research has matured over the last decade, and with it the need for more detailed diagnostics has increased. One main gap in diagnostics is the ability to obtain a quantitative measure of transition of stable to unstable combustion in combustors. In an effort to move in this direction, two methods have been applied simultaneously to study the dynamic of the transition from stable to unstable combustion mode of premixed flame optically accessible in an industrial combustor. It has been demonstrated that the optical integration of chemiluminescence emission of the flame at different modes and digital acquisition processing is a powerful combination in the investigation the complex flame dynamics.

The main chemiluminescent emitters considered in this study are OH*, CH* and C₂* species. The results show that, for stable combustion, the fluctuations of chemical species are low. Prior to onset of unstable combustion, the amplitude of oscillation increased rapidly and suddenly to a new margin. In unstable combustion the mean and RMS (root mean square) of the signals are increased. This study makes available very detailed power spectra of each radical and the acoustic signal. Also, in order to classify different phase of combustion process and better recognize the transition mechanisms leading to combustion instability, phase space diagrams between two signals have been presented and analysed. For farther information about the acoustic pressure and chemiluminescence emissions of CH*, OH* and C₂ *, the cross-correlations of these signals have been calculated.

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