Oscillation frequency measurement of gaseous diffusion flames using electrostatic sensing techniques

The oscillation frequency of a burner flame is closely related to the combustion conditions and flame stability. Oscillation frequency measurement is essential for optimized operation of the combustion process. In this paper, the novel use of electrostatic sensors in conjunction with power spectral analysis is presented for the oscillation frequency measurement of a gaseous laminar diffusion flame. Experimental tests carried out on a combustion rig demonstrate that the developed system realises oscillation frequency measurement with a relative deviation from the reference value from an imaging system within ±6% over a constant fuel flow rate from 0.60 L/min to 0.80 L/min. The oscillation frequency increases with the fuel flow rate and the oscillation frequencies in different regions of the diffusion flame are similar for each fuel flow rate. Under varying fuel flow rate conditions, the system can measure the instantaneous oscillation frequency with a relative deviation from the reference value from an imaging system mostly between -10% and 0%.