Laser Diagnostics for Reacting Flows

Abstract

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instmcl data needed, and completing and reviewing this collection of information. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)Stanford University 651 Serra Street Stanford CA 94305 PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)AFOSR/NA SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution is unlimited SUPPLEMENTARY NOTES 02114. ABSTRACT Advanced optical diagnostic techniques relevant to propulsion were investigated. The techniques studied were based on laser spectroscopy, with emphasis on spectrally-resolved absorption and laser-induced fluorescence (LIF). Spectrally narrow, continuous wave (cw) lasers allowed innovative diagnostics based on spectral lineshapes, while pulsed lasers provided intense bursts of photons needed for techniques based on LIF.Accomplishments of note included: studies of fundamental ketone in support of PLIF imaging diagnostics for fuel vapor and temperature; fabrication of a high-pressure flat-flame burner and its use to develop quantitative strategies for PLIF imaging of NO and temperature in high-pressure combustion systems; the first observation of ultraviolet (UV) LIF of CO2; continued development of a new imaging diagnostic based on infrared planar laser-induced fluorescence (IR PLIF); discovery of strong UV absorption by CO2 at high temperatures and measurements of the absorption cross sections; investigations of the impact of UV CO2 absorption on existing diagnostic strategies for NO; initial demonstrations of a new wavelength-multiplexed laser extinction diagnostic allowing measurements in multiphase fuel flows; and continued development of wavelength-multiplexed tunable diode laser absorption sensors and their application to measure temperature and species concentration in practical combustion environments, including scramjet and gas turbine combustor test rigs at the Air Force Research Laboratory Propulsion Directorate. SUBJECT TERMS