Axisymmetric Linear Hyperspectral Absorption Spectroscopy and Residuum-Based Parameter Selection on a Counter Flow Burner

Chemical species tomography enables non-invasive measurements of temperatures and concentrations in gas phase processes. In this work, we demonstrate the recently introduced linear hyperspectral absorption tomography (LHAT) on an axisymmetric counterflow burner used for speciation studies of Oxyfuel combustion. As LHAT reconstructs spectrally resolved local absorption coefficient spectra, the physical plausibility of these reconstructed spectra degrades with an over-regularization of the tomographic problem. As presented in this work, this behavior can be employed in a novel regularization parameter choice method based on the residuals of local spectroscopic fits to the reconstructed spectra. After determining the regularization parameter, the reconstructions of the temperature and water mole fraction profiles of different flames are compared to numerical simulations, showing a good agreement.