Quantitative hydroxyl concentration calibration by use of a flat flame burner, thermocouple and Planar Laser Induced Fluorescence (PLIF) system

A quantitative concentration calibration system has been constructed for a Planar Laser Induced Fluorescence (PLIF) system that was just recently established as being capable of accurately imaging the qualitative hydroxyl (OH) concentration in transient flames within a cylindrical constant volume vessel at desired radii. In conjunction with the PLIF system, this calibration system includes a flat flame burner, a thermocouple and positioning stand, gas flow meters, and control valves.;A calibration procedure was developed in order to apply absolute concentrations of OH to otherwise relative measurements obtained from the combustion vessel and to form a basis for future experiments. This procedure involved measuring the temperature in the hot gas region of a hydrogen-air flame, correcting for radiation losses, calculating the equilibrium OH concentrations at the measured temperature and applying these values to fluorescence images taken of the burner. Preliminary results are shown and discussed in relation to experimental uncertainties.;Modifications made to the existing system that significantly improved performance and enabled the capture of satisfactory fluorescence images are discussed.