Turbulent nonpremixed flames of methane near extinction: Mean structure from raman measurements

Journal Article · Tue Mar 01 04:00:00 EST 1988 · Combust. Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(88)90062-4· OSTI ID:7030295

Masri, A R; Bilger, R W; Dibble, R W

Spontaneous Raman-Rayleigh measurements of species concentration-temperature have been made in turbulent nonpremixed flames of methane near extinction. The means and rms of fluctuations of temperature, density, mixture fraction, and the mass fractions of CH/sub 4/, O/sub 2/, N/sub 2/, H/sub 2/O, H/sub 2/, CO, and CO/sub 2/ are presented in this paper. The mean Raman-Rayleigh results compare favorably with probe measurements of species concentrations and temperature made in similar flames. At a given axial location, unreactedness (finite rate kinetics) and not unmixedness (high (xi-tilde''/sup 2/)/sup 1/2/) explains almost entirely the change in the flame structure. As the flame approaches extinction, the Favre averaged mass fractions of CH/sub 4/ and O/sub 2/ increase while those of the products H/sub 2/O, H/sub 2/, CO and CO/sub 2/ decrease. The rms of fluctuations in the temperature and mass fractions O/sub 2/, H/sub 2/O, H/sub 2/, CO, and CO/sub 2/ decrease as well. ALthough these results favor the concept of a diffuse flame structure, the existence of partially premixed laminar diffusion flamelets cannot be excluded.

• Research Organization: Dept. of Mechanical Engineering, The Univ. of Sydney, NSW 2006 (AU)
• OSTI ID: 7030295
• Journal Information: Combust. Flame; (United States), Journal Name: Combust. Flame; (United States) Vol. 71:3; ISSN CBFMA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ALKANES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
ELEMENTS
FLAME PROPAGATION
FLAMES
FLUID FLOW
HYDROCARBONS
HYDROGEN
HYDROGEN COMPOUNDS
KINETICS
LAMINAR FLOW
METHANE
NITROGEN
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
RAMAN EFFECT
REACTION KINETICS
TURBULENCE
WATER