Dynamic Flame Stability Diagnosis of Inverse Jet Flame using CH* Chemiluminescence

摘要

The paper proposes a new methodology to sense dynamic flame stability in a Circumferentially Arranged Fuel Port Inverse Jet Flame (IJF) burner. This strategy is devised using the wavelet technique of the CH* signature to overcome the effects of white noise from the spectrum of the chemiluminescent signal. The flame stability regimes, namely the stable flame, onset of liftoff, and main flame extinction, are identified. The high-speed camera records the transient events during local attachment-detachment of base flame and main flame extinction. The higher level of fluctuations during the main flame extinction is attributed to the flame-fingering at the proximity of the flame neck. Besides this, the statistical analysis indicates an increase in higher cumulative frequency count for lower values of CH* intensity at the main flame extinction. The power spectral analysis denotes high-frequency oscillations during the onset of flame liftoff. A semi-empirical correlation based on the Coefficient of Variance and Momentum Flux Ratio is proposed for identifying the dynamic flame stability. The experimental results show that this technique can be used as a reliable and active control system to avert lean flame blowout.