THE APPLICATION OF SPONTANEOUS VIBRATIONAL RAMAN SCATTERING FOR TEMPERATURE MEASUREMENTS IN HIGH PRESSURE LAMINAR FLAMES

摘要

Ultraviolet (UV) spontaneous vibrational Raman scattering is used for temperature measurements in premixed methane/air flat flames burning at 1―5 bar. The measured spectra indicate that the peak and integrated intensities of the O_2 and N_2 Stokes Raman signals are linearly proportional to pressure at room temperature. Temperature measurements are made by spectral-fit of the theoretical spectra to the measured N_2 Q-branch spectra. The Raman-measured temperatures agree well with the thermocouple-measured temperatures. The line widths (full width at half maximum; FWHM) of the trapezoidal slit function in flames at 1―5 bar are used to extrapolate the line widths for pressures up to 30 bar. The calculated theoretical spectra indicate that the spectral-fit method can be used to determine flame temperature at conditions close to adiabatic and 30 bar with an adequate accuracy.