TURBULENT NONPREMIXED FLAMES OF METHANE NEAR EXTINCTION - MEAN STRUCTURE FROM RAMAN MEASUREMENTS

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//4, O//2, N//2, H//2O, H//2, CO, and CO//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 explains almost entirely the change in the flame structure.