DIODE-LASER SENSOR FOR MEASUREMENTS OF CO, CO2, AND CH4 IN COMBUSTIONFLOWS

A diode laser sensor has been applied to monitor CO, CO2, and CH4 in c ombustion gases with absorption spectroscopy and fast extraction-sampl ing techniques. Survey spectra of the CO 3v band (R branch) and the 2v (1) + 2v(2)(0) + v(3) CO2 band (R branch) near 6350 cm(-1) and H2O lin es from the v(1) + 2v(2) and 2v(2) + v(3) bands in the spectral region from 6345 to 6660 cm(-1) were recorded and compared with calculated s pectra (from the HITRAN 96 database) to select optimum transitions for species detection. Species concentrations above a laminar, premixed, methane-air flame were determined from measured absorption in a fast-f low multipass absorption cell containing probe-sampled combustion gase s; good agreement was found with calculated chemical equilibrium value s. (C) 1997 Optical Society of America.