- Author
- Smyth, K. C. | Tjossem, P. J. H.
- Title
- Relative H-Atom and O-Atom Concentration Measurements in a Laminar, Methane/Air Diffusion Flame.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Book or Conf
- Combustion Institute, Symposium (International) on Combustion, 23rd. July 22-27, 1990, Combustion Institute, Pittsburgh, PA, Orleans, France, 1829-1837 p., 1991
- Keywords
- combustion | diffusion flames | concentration measurement | laminar flames | methane | air
- Abstract
- Relative H-atom and O-atom concentration profiles have been measured in a laminar, co-flowing methane/air diffusion flame burning at atmospheric pressure. Multiphoton ionization (2 + 1 process at 243 nm) has been used to detect H atoms, while laser-induced fluorescence at 845 nm excited by two-photon absorption at 226 nm was employed to observe O atoms. In both cases it was found that low photon intensities were required in order to avoid the photolytic production of the species of interest. Doppler-free measurements were carried out using a retroreflected-beam geometry in order to provide sufficient signal levels. Under these experimental conditions it is necessary to correct the raw profile data for variations in collisional quenching and electron detection sensitivity as a function of flame position. Establishing absolute radical concentrations is discussed in terms of partial equilibrium considerations and detailed flame structure calculation.