1992/04/01 by Joseph A. Wehrmeyer, Joseph Wehrmeyer, Tsarng-Sheng Cheng +1
Chemical Engineering · Chemistry · Engineering · #Advanced Combustion Engine Technologies #Analytical Chemistry (journal) #Chemistry #Coherent anti-Stokes Raman spectroscopy #Combustion and flame dynamics #Excimer laser #Laser #Laser-induced fluorescence #Materials science #Optics #Physics #Pulse (music) #Raman scattering #Raman spectroscopy #Spectroscopy and Laser Applications
paper · doi:10.1364/ao.31.001495
openalex publication_date 1992/04/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/23
Using a narrow-band tunable KrF excimer laser as a spontaneous vibrational Raman scattering source, we demonstrate that single-pulse concentration and temperature measurements, with only minimal fluorescence interference, are possible for all major species (O(2), N(2), H(2)O, and H(2)) at all stoichiometries (fuel-lean to fuel-rich) of H(2)-air flames. Photon-statistics-limited precisions in these instantaneous and spatially resolved single-pulse measurements are typically 5%, which are based on the relative standard deviations of single-pulse probability distributions. Optimal tuning of the narrow-band KrF excimer laser (248.623 nm) for the minimization of OH A(2)Sigma-X(2)II and O(2)B(3)Sigma(u)(-)-X(3)Sigma(g)(-) fluorescence interference is determined from fluorescence excitation spectra. In addition to the single-pulse N(2) Stokes/anti-Stokes ratio temperature measurement technique, a time-averaged temperature measurement technique ispresented that matches the N(2) Stokes Raman spectrum to theoretical spectra by using a single intermediate sta frequency to account for near-resonance enhancement. Raman flame spectra in CH(4)-air flames are presented that have good signal-to-noise characteristics and show promise for single-pulse UV Raman measurements in hydrocarbon flames.