title: Measurements of OH mole fraction and temperature up to 20 kHz by using a diode-laser-based UV absorption sensor.
abstract: Diode-laser-based sum-frequency generation of ultraviolet (UV) radiation at 313.5 nm was utilized for high-speed absorption measurements of OH mole fraction and temperature at rates up to 20 kHz. Sensor performance was characterized over a wide range of operating conditions in a 25.4 mm path-length, steady, C2H4-air diffusion flame through comparisons with coherent anti-Stokes Raman spectroscopy (CARS), planar laser-induced fluorescence (PLIF), and a two-dimensional numerical simulation with detailed chemical kinetics. Experimental uncertainties of 5% and 11% were achieved for measured temperatures and OH mole fractions, respectively, with standard deviations of < 3% at 20 kHz and an OH detection limit of < 1 part per million in a 1 m path length. After validation in a steady flame, high-speed diode-laser-based measurements of OH mole fraction and temperature were demonstrated for the first time in the unsteady exhaust of a liquid-fueled, swirl-stabilized combustor. Typical agreement of approximately 5% was achieved with CARS temperature measurements at various fuel/air ratios, and sensor precision was sufficient to capture oscillations of temperature and OH mole fraction for potential use with multiparameter control strategies in combustors of practical interest.
authors.affiliation: Innovative Scientific Solutions, 2766 Indian Ripple Road, Dayton, Ohio 45440, USA. trmeyer@innssi.com
authors.forename: Terrence R
authors.initials: TR
authors.lastname: Meyer
authors.forename: Sukesh
authors.initials: S
authors.lastname: Roy
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Anderson
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Miller
authors.forename: Viswanath R
authors.initials: VR
authors.lastname: Katta
authors.forename: Robert P
authors.initials: RP
authors.lastname: Lucht
authors.forename: James R
authors.initials: JR
authors.lastname: Gord