In situ determination of N-2 broadening coefficients in flames for rotational CARS thermometry

• Total N-2 S-branch broadening coefficients have been measured in situ as a function of radial position in a highly sooting ethylene diffusion flame by the use of time-resolved dual-broadband picosecond pure rotational CARS (RCARS). Time-domain measurements of the J-dependent N-2 rotational coherence decays in the flame were used to determine the broadening coefficients, and these coefficients were then used in the spectral fitting routine for the determination of temperature and [O-2]/[N-2] ratio in the flame. Corrections of up to 125 K are found when compared to spectral fitting using an ECS self-broadened N-2 linewidth model. The presented technique effectively takes into account contributions to the N-2 linewidths from all collision partners without any a priori knowledge of relative species concentrations. Published by Elsevier Inc. on behalf of The Combustion Institute.

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

Time-resolved spectroscopy

Raman linewidths

CARS

Ultrafast

Soot

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)