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

Abstract

Chemical species tomography enables non-invasive measurements of temperatures andconcentrations in gas phase processes. In this work, we demonstrate the recently introducedlinear hyperspectral absorption tomography (LHAT) on an axisymmetric counterflow burner usedfor speciation studies of Oxyfuel combustion. As LHAT reconstructs spectrally resolved localabsorption coefficient spectra, the physical plausibility of these reconstructed spectra degradeswith an over-regularization of the tomographic problem. As presented in this work, this behaviorcan be employed in a novel regularization parameter choice method based on the residuals of localspectroscopic fits to the reconstructed spectra. After determining the regularization parameter,the reconstructions of the temperature and water mole fraction profiles of different flames arecompared to numerical simulations, showing a good agreement.

Exploring the combustion chemistry of anisole in laminar counterflow diffusion-flames under oxy-fuel conditions

“…The quartz nozzle with an orifice diameter of 30 μm extracts the gas samples directly from the flames by a molecular beam generated from three stages of vacuum. The small orifice excludes the influence of neighboring zones on measurements along the centerline, which was investigated on the same setup by optical measurements in previous work [30]. The extracted molecules in the chamber are ionized by the electrons from thermionic emissions of a heated tungsten filament.…”