Absolute concentration measurements of atomic hydrogen in subatmospheric premixed H/sub 2//O/sub 2//N/sub 2/ flat flames with photoionization controlled-loss spectroscopy

Journal Article · Wed Jul 15 04:00:00 EDT 1987 · Appl. Opt.; (United States)

DOI:https://doi.org/10.1364/AO.26.002881· OSTI ID:6421892

Salmon, J T; Laurendeau, N M

An experimental protocol, using photoionization controlled-loss spectroscopy (PICLS), has been developed for obtaining absolute number densities of atomic hydrogen from laser-induced fluorescence measurements in flames. Two laser beams are employed, the first to excite hydrogen atoms from the ground state to the second excited state via two-photon absorption and the second to strongly photoionize the excited atoms. The resulting fluorescence measurements are independent of quenching. A model is presented that assures the viability of PICLS as long as the photoionization rate is greater than or equal to the quenching rate. The model is verified in fuel-lean, stoichiometric, and fuel-rich flat premixed H/sub 2//O/sub 2//N/sub 2/ flames at pressures of 20 and 72 Torr. Over this range in pressure, the ratio of number densities obtained from PICLS to those calculated from partial equilibrium is constant to within 20%. Most of the error arises from the sensitivity of the partial equilibrium calculations to small uncertainties in both the fuel-oxidizer ratio and the measured OH concentration. Because of the quenching-independent nature of PICLS, quantitative fluorescene measurements can be made by calibrating at a single favorable flame condition.

• Research Organization: Purdue University, School of Mechanical Engineering, Flame Diagnostics Laboratory, West Lafayette, Indiana 47907
• OSTI ID: 6421892
• Journal Information: Appl. Opt.; (United States), Journal Name: Appl. Opt.; (United States) Vol. 26:14; ISSN APOPA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
400800 -- Combustion
Pyrolysis
& High-Temperature Chemistry
CHEMICAL ANALYSIS
CHEMISTRY
ELEMENTS
EMISSION SPECTROSCOPY
FLAMES
FLUORESCENCE
HYDROCARBONS
HYDROGEN
IONIZATION
LASER SPECTROSCOPY
LAWRENCE LIVERMORE LABORATORY
LUMINESCENCE
MATHEMATICAL MODELS
MULTI-PHOTON PROCESSES
NATIONAL ORGANIZATIONS
NONMETALS
ORGANIC COMPOUNDS
PHOTOCHEMISTRY
PHOTOIONIZATION
QUANTITATIVE CHEMICAL ANALYSIS
SPECTROSCOPY
US AEC
US DOE
US ERDA
US ORGANIZATIONS