Flicker measurement of burner flames through electrostatic sensing and spectral analysis

摘要

Measurement of the flicker frequency of a burner flame is desirable to achieve an in-depth understanding of the dynamics of combustion processes. This paper presents a novel method based on electrostatic sensing to measure the flicker frequency of a hydrocarbon flame. The flame flickering behaviour is determined by measuring the concentration changes of ions in the flame and characterized by processing the signals from an electrostatic sensor. Power spectral analysis of the sensor signals is performed to obtain their frequency components. Experimental tests were conducted on a laboratory-scale combustion test rig for different equivalence ratios. Flame images were simultaneously acquired using a high-speed camera to provide a direct comparison between the results from the electrostatic sensors and those from the imaging approach. It is found that the flickering frequency of the burner flame decreases with the equivalence ratio. The results obtained demonstrate that the electrostatic sensing method can measure the flickering frequency of the flame and is useful for the assessment of flame stability.