Patent ID: 8825214

Claim:
A method for analyzing and controlling a combustion process in a combustion chamber of a gas turbine by measurement of an absorption spectrum, the method comprising: providing a molecule absorption spectrum including a range of absorption lines for selected molecules of gas involved in the combustion process in the combustion chamber by using a databank containing standards for molecule absorption spectra including the selected molecules of the gas, and generating a calibration model absorption spectrum containing absorption lines for the selected molecules of the gas at a plurality of temperatures, pressures, and concentrations of the selected molecules of the gas using an algorithm; providing one or more tunable laser sources, which are tunable over the spectrum containing absorption lines of a selected species of the gas in the combustion chamber; tuning the one or more tunable laser sources to a wavelength range that contains absorption wavelengths of the selected species in the gas; directing laser light from the one or more tunable laser sources through the gas in the combustion chamber via transmitting optics; detecting the laser light reflected off a boundary wall of the combustion chamber via receiving optics and a detection device; generating a measured absorption spectrum for the selected species of the gas in the chamber, based on the detected laser light; analyzing the measured absorption spectrum using a signature recognition algorithm by applying a cross-correlation between the calibration model absorption spectrum and the measured absorption spectrum; deriving, simultaneously, from the cross-correlation, values for a gas temperature of the selected molecules of the gas in the chamber by using the same algorithm as was used for the generation of the calibration model absorption spectrum; generating control values for the combustion process based on the derived values for the gas temperature, and directing the control values to a combustion chamber operation control unit; and controlling the combustion process using the generated control values.