TY - GEN
T1 - Pure-Rotational fs/ps CARS measurements of temperature and concentration using a second-harmonic bandwidth-compressed probe
AU - Kearney, Sean P.
AU - Scoglietti, Daniel J.
PY - 2014
Y1 - 2014
N2 - A hybrid fs/ps pure-rotational CARS scheme is demonstrated in the product gases of premixed hydrogren/air and ethylene/air flat flames. Near-transform-limited, broadband femtosecond pump and Stokes pulses impulsively prepare a rotational Raman coherence, which is later probed by a high-energy, frequency-narrow picosecond pulse, generated by sum-frequency mixing of linearly chirped broadband pulses with conjugate temporal phase. Spectral fitting is demonstrated for both shot-averaged and single-laser-shot spectra. Measurement accuracy is quantified by comparison to adiabatic-equilibrium calculations for the hydrogen/air flames, and by comparison to nanosecond CARS measurements for the ethylene/air flames. Temperature-measurement precision is 1-3% and O2/N2 precision is 2-10% based on histograms constructed from 1000 single-shot measurements acquired at a data rate of 1 kHz. These results indicate that hybrid fs/ps rotational CARS is a quantitative tool for kHz-rate combustion temperature/species data.
AB - A hybrid fs/ps pure-rotational CARS scheme is demonstrated in the product gases of premixed hydrogren/air and ethylene/air flat flames. Near-transform-limited, broadband femtosecond pump and Stokes pulses impulsively prepare a rotational Raman coherence, which is later probed by a high-energy, frequency-narrow picosecond pulse, generated by sum-frequency mixing of linearly chirped broadband pulses with conjugate temporal phase. Spectral fitting is demonstrated for both shot-averaged and single-laser-shot spectra. Measurement accuracy is quantified by comparison to adiabatic-equilibrium calculations for the hydrogen/air flames, and by comparison to nanosecond CARS measurements for the ethylene/air flames. Temperature-measurement precision is 1-3% and O2/N2 precision is 2-10% based on histograms constructed from 1000 single-shot measurements acquired at a data rate of 1 kHz. These results indicate that hybrid fs/ps rotational CARS is a quantitative tool for kHz-rate combustion temperature/species data.
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M3 - Conference contribution
AN - SCOPUS:84902815752
SN - 9781624102561
T3 - 52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014
BT - 52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014
PB - American Institute of Aeronautics and Astronautics Inc.
T2 - 52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014
Y2 - 13 January 2014 through 17 January 2014
ER -