Quantitative picosecond laser-induced fluorescence measurements of nitric oxide in flames

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

Abstract

Quantitative concentrations measurements using time-resolved laser-induced fluorescence have been demonstrated for nitric oxide (NO) in flame. Fluorescence lifetimes measured using a picosecond Nd:YAG laser and optical parametric amplifier system have been used to directly compensate the measured signal for collisional quenching and evaluate NO concentration. The full evaluation also includes the spectral overlap between the ∼15cm-1 broad laser pulse and multiple NO absorption lines as well as the populations of the probed energy levels. Effective fluorescence lifetimes of 1.2 and 1.5ns were measured in prepared NO/N2/O2 mixtures at ambient pressure and temperature and in a premixed NH3-seeded CH4/N2/O2 flame, respectively. Concentrations evaluated from measurements in NO/N2/O2 mixtures with NO concentrations of 100-600ppm were in agreement with set values within 3% at higher concentrations. An accuracy of 13% was estimated by analysis of experimental uncertainties. An NO profile measured in the flame showed concentrations of ∼1000ppm in the post-flame region and is in good agreement with NO concentrations predicted by a chemical mechanism for NH3 combustion. An accuracy of 16% was estimated for the flame measurements. The direct concentration evaluation from time-resolved fluorescence allows for quantitative measurements in flames where the composition of major species and their collisional quenching on the probed species is unknown. In particular, this is valid for non-stationary turbulent combustion and implementation of the presented approach for measurements under such conditions is discussed.

Detaljer

Författare
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Energiteknik

Nyckelord

Originalspråkengelska
Sidor (från-till)4533-4540
TidskriftProceedings of the Combustion Institute
Volym36
Utgåva nummer3
Tidigt onlinedatum2015 dec 3
StatusPublished - 2017
PublikationskategoriForskning
Peer review utfördJa