TUNABLE DIODE-LASER ABSORPTION-MEASUREMENTS OF METHANE AT ELEVATED-TEMPERATURES

A diode-laser sensor system based on absorption spectroscopy technique s has been developed to monitor CH4 nonintrusively in high-temperature environments. Fundamental spectroscopic parameters, including the lin e strengths of the transitions in the R(6) manifold of the 2 nu(3) ban d near 1.646 mu m, have been determined from high-resolution absorptio n measurements in a heated static cell. In addition, a corrected expre ssion for the CH4 partition function has been validated experimentally over the temperature range from 400 to 915 K. Potential applications of the diode-laser sensor system include process control, combustion m easurements, and atmospheric monitoring.