TY - JOUR
T1 - Fluorescence-free quantitative measurements of nitric oxide and major species in an ammonia/air flame with Raman spectroscopy
AU - Zubairova, Alsu
AU - Kim, Haisol
AU - Aldén, Marcus
AU - Brackmann, Christian
PY - 2023
Y1 - 2023
N2 - Raman spectroscopy is a powerful technique that allows for simultaneous measurements of multiple species; however, it suffers from low signal intensity and, in diagnostics of ammonia (NH3) combustion, strong flame fluorescence. The current work re-introduces a multipass setup to perform enhanced quantitative Raman spectroscopy measurements of major species and nitric oxide (NO) in a premixed laminar lean (π = 0.9) NH3 flame. A way to deal with the strong flame reaction-zone fluorescence is proposed and validated. The measurements were performed using both the second (532 nm, NO detection) and third (355 nm, major species and temperature) harmonics of an Nd:YAG laser. The acquired data sets were compared to the simulation data obtained with two chemical kinetic mechanisms. The reported average post-flame concentration of NO reaches a plateau at 3900 ± 120 ppm, and the detection limit is 700 ppm. The 355 nm excitation wavelength proved to provide close to no flame fluorescence, which allowed for measurements across the entire flame from reactants to products. Thus, major species profiles were acquired, and the concentration and temperature results are in good agreement with the simulation data. Lastly, possible error sources are estimated and ways to minimize them are proposed.
AB - Raman spectroscopy is a powerful technique that allows for simultaneous measurements of multiple species; however, it suffers from low signal intensity and, in diagnostics of ammonia (NH3) combustion, strong flame fluorescence. The current work re-introduces a multipass setup to perform enhanced quantitative Raman spectroscopy measurements of major species and nitric oxide (NO) in a premixed laminar lean (π = 0.9) NH3 flame. A way to deal with the strong flame reaction-zone fluorescence is proposed and validated. The measurements were performed using both the second (532 nm, NO detection) and third (355 nm, major species and temperature) harmonics of an Nd:YAG laser. The acquired data sets were compared to the simulation data obtained with two chemical kinetic mechanisms. The reported average post-flame concentration of NO reaches a plateau at 3900 ± 120 ppm, and the detection limit is 700 ppm. The 355 nm excitation wavelength proved to provide close to no flame fluorescence, which allowed for measurements across the entire flame from reactants to products. Thus, major species profiles were acquired, and the concentration and temperature results are in good agreement with the simulation data. Lastly, possible error sources are estimated and ways to minimize them are proposed.
KW - Ammonia
KW - Multipass
KW - Premixed flame
KW - Raman spectroscopy
U2 - 10.1016/j.proci.2022.07.136
DO - 10.1016/j.proci.2022.07.136
M3 - Article
AN - SCOPUS:85138725546
SN - 1540-7489
VL - 39
SP - 1317
EP - 1324
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
IS - 1
ER -