Rodolfo, Barron Jimenez (2004-12). Application of an all-solid-state diode-laser-based sensor for carbon monoxide detection by optical absorption in the 4.4 ? 4.8 um spectral region. Doctoral Dissertation. Thesis uri icon

abstract

  • An all-solid-state continuous-wave (cw) laser system for mid-infrared absorption measurements of the carbon monoxide (CO) molecule has been developed and demonstrated. The single-mode, tunable output of an external-cavity diode laser (ECDL) is difference-frequency mixed (DFM) with the output of a 550-mW diode-pumped cw Nd:YAG laser in a periodically-poled lithium niobate (PPLN) crystal to produce tunable cw radiation in the mid-infrared. The wavelength of the 860-nm ECDL can be coarse tuned between 860.78 to 872.82 nm allowing the sensor to be operated in the 4.4 ? 4.8 um region. Results from single-pass mid-IR direct absorption experiments for CO concentration measurements are discussed. CO measurements were performed in CO/CO2/N2 mixtures in a room temperature gas cell that allowed the evaluation of the sensor operation and data reduction procedures. Field testing was performed at two locations: in the exhaust of a well-stirred reactor (WSR) at Wright-Patterson Air Force Base and the exhaust of a gas turbine at Honeywell Engines and Systems. Field tests demonstrated the feasibility of the sensor for operation in harsh combustion environments but much improvement in the sensor design and operation was required. Experiments in near-adiabatic hydrogen/air CO2-doped flames were performed featuring two-line thermometry in the 4.8 um spectral region. The sensor concentration measurement uncertainty was estimated at 2% for gas cell testing. CO concentration measurements agreed within 15% of conventional extractive sampling at WSR, and for the flame experiments the repeatability of the peak absorption gives a system uncertainty of 10%. The noise equivalent CO detection limit for these experiments was estimated at 2 ppm per meter, for combustion gas at 1000 K assuming a SNR ratio of 1.
  • An all-solid-state continuous-wave (cw) laser system for mid-infrared absorption measurements

    of the carbon monoxide (CO) molecule has been developed and demonstrated. The single-mode, tunable

    output of an external-cavity diode laser (ECDL) is difference-frequency mixed (DFM) with the output of a

    550-mW diode-pumped cw Nd:YAG laser in a periodically-poled lithium niobate (PPLN) crystal to

    produce tunable cw radiation in the mid-infrared. The wavelength of the 860-nm ECDL can be coarse

    tuned between 860.78 to 872.82 nm allowing the sensor to be operated in the 4.4 ? 4.8 um region. Results

    from single-pass mid-IR direct absorption experiments for CO concentration measurements are discussed.

    CO measurements were performed in CO/CO2/N2 mixtures in a room temperature gas cell that allowed the

    evaluation of the sensor operation and data reduction procedures. Field testing was performed at two

    locations: in the exhaust of a well-stirred reactor (WSR) at Wright-Patterson Air Force Base and the

    exhaust of a gas turbine at Honeywell Engines and Systems. Field tests demonstrated the feasibility of the

    sensor for operation in harsh combustion environments but much improvement in the sensor design and

    operation was required. Experiments in near-adiabatic hydrogen/air CO2-doped flames were performed

    featuring two-line thermometry in the 4.8 um spectral region. The sensor concentration measurement

    uncertainty was estimated at 2% for gas cell testing. CO concentration measurements agreed within 15%

    of conventional extractive sampling at WSR, and for the flame experiments the repeatability of the peak

    absorption gives a system uncertainty of 10%. The noise equivalent CO detection limit for these

    experiments was estimated at 2 ppm per meter, for combustion gas at 1000 K assuming a SNR ratio of 1.

publication date

  • December 2004