Quantitative diagnostics of a methane/air mini‐flame by Raman spectroscopy

Abstract

We present a quantitative investigation by linear Raman spectroscopy of a methane/air premixed flame from a commercial burner. Rotational temperatures and absolute densities of the major species, N 2 , O 2 , CH 4 , CO 2 , and H 2 O have been measured in a grid of points across the flame section. Axial and radial profiles of temperature and densities are reported, and mass balances along the flame axis are discussed. We show the capabilities of this technique for combustion studies by using currently available standard detectors and spectrometers.

A study of the Raman spectrum of CO2 using an algebraic approach

“…From these derivatives, the complete set of lines located in the range 1150 − 1460 cm −1 is calculated. Therefore, this work could help in the quantitative diagnostics of combustion flames [5]. Our approach is consistent with the previous analysis of the vibrational excitations of CO 2 , where symmetry coordinates are first substituted by the corresponding bosonic creation and annihilation operators, and then a canonical transformation is applied in order to introduce local operators which are subsequently anharmonized.…”

“…Regarding vibrational excitations, infrared and Raman spectroscopy provide the experimental data needed to achieve this goal. In a recent work, the Raman spectrum of CO 2 at 1750 K from a methane/air flame in the 1150 − 1460 cm −1 range was reported [5]. This spectrum can be used to test the vibrational wavefunctions as long as a suited description of the dependence of the molecular polarizability tensor on the vibrational motions is available.…”

“…[5]. To this end we use the eigenstates provided by the U (2) × U (3) × U (2) model to compute the transition moments of the mean polarizability.…”

Raman spectroscopy at the beginning of the twenty‐first century

“…The paper of Fernandez et al 21 reports on the application of linear Raman spectroscopy on combustion processes. A model methane-air burner has been used, which produces a stable laminar flame.…”

Raman spectra of methane, ethylene, ethane, dimethyl ether, formaldehyde and propane for combustion applications

“…[1][2][3][4][5] The line-imaging Raman/Rayleigh scattering instrument at Sandia National Laboratories (SNL) provides instantaneous measurements of temperature and major species concentrations (N 2 , O 2 , CO 2 , CO, H 2 O, H 2 and CH 4 ) in flames, over a 6 mm probe line, with a spatial resolution of ~100 microns. The instrument is routinely applied to measurements in laboratory-scale flames that are specifically designed to advance the understanding of the turbulence-chemistry interaction, and to provide validation databases for computational models.…”