Simultaneous space- and time-resolved measurements of the concentrations of CH4, O2, N2, H2O, H2, CO, and CO2 have been made using spontaneous Raman scattering, in the blue regions of CH4 turbulent nonpremixed flames. The temperature is measured from the Rayleigh scattered signal. A "fluorescence" interference, which is broadband and contaminates in varying degrees the Rayleigh and all the Raman lines, is believed to be due to a number of molecules or flame radicals, including C2 and CN or even incandescence of small particle nuclei. The "fluorescence" has been monitored at a bandhead of C2 (516.5 nm) and its effect reduced by placing a Polaroid filter at the entrance slit of the spectrometer. The remaining "fluorescence" has been corrected for, using correction curves generated from measurements made in a laminar counterflow CH4 diffusion flame and a diluted CH4 N2 = 1 2 (by vol.) laminar diffusion flame. Measurements of CO and CO2 are not reliable in the rich regions of the flame where the "fluorescence" is intense. With minor modifications to the optical system, CO and CO2 could also be measured with acceptable accuracy in regions of intense "fluorescence" and the "fluorescence" correction further refined. This work is considered to be an important extension of the applications of spontaneous Raman scattering as a measurement technique in flames.
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering
- Fuel Technology
- Energy Engineering and Power Technology
- General Physics and Astronomy