Importance

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Abstract

The subject of the present patent is a method to determine the flame shape of a swirling flame in a steady-operating burner in a closed combustion chamber. The broadband combustion noise of the burner is sensed inside the combustion chamber, and the spectrum and the sound pressure levels are calculated from the acoustic vibrations of the process. The conclusions are made on this data to determine the flame shape. To determine the governing frequencies, the burner is investigated at various operating conditions. At least one parameter from the fuel flow rate, combustion air flow rate, and the swirl number is varied in the physically accessible range of the burner. The spectrum is divided into 0-500 Hz, 501-2000 Hz, and 2 kHz-6 kHz frequency ranges, then the amplitudes at the band center frequencies are calculated. Based on either the temporal analysis of band center frequencies or the temporal variation of their ratio or the two combined, the shape of the swirling flame can be determined.

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First Claim