SPECTROSCOPIC METHOD FOR DETERMINATION OF THE TWO-DIMENSIONAL PROFILE OF A FLAME IN VIS-NIR WAVELENGTH REGION

Abstract

This study introduces a novel, noncontact optical technique for solving a two-dimensional, ill-posed problem in temperature tomography inside the firebox of a commercial coal power plant. For the determination of the 2D temperature distribution and the coefficients of attenuation, we have taken into account four optical probes positioned at the corners of the combustion chamber. The probes were coupled to four identical spectrometers via optical fiber cables. For the simulation, Aurora 4000 spectrometers were used to measure spectral radiances between 780 nm and 900 nm. The simulated measurement and reconstruction setup are based on a spectroscopy approach with the assumption of gray body radiation from the medium. This method has been confirmed based on experimental data from a 1D case where we had measurements in a commercial coal power plant.
Overall, this new approach demonstrates the possibility of conducting measurements in a simpler manner, where the lower spatial resolution of the measurement system is compensated for by an increased spectral resolution. This novel approach to temperature tomography is simpler compared to similar methods involving laser absorption spectroscopy and expensive multispectral and hyperspectral CCD cameras.