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Title: Interference free spontaneous Raman spectroscopy for measurements in rich hydrocarbon flames

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Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Proceedings of the Combustion Institute
Additional Journal Information:
Journal Volume: 35; Journal Issue: 3; Related Information: CHORUS Timestamp: 2017-05-17 09:41:52; Journal ID: ISSN 1540-7489
Country of Publication:
United States

Citation Formats

Magnotti, G., Geyer, D., and Barlow, R. S. Interference free spontaneous Raman spectroscopy for measurements in rich hydrocarbon flames. United States: N. p., 2015. Web. doi:10.1016/j.proci.2014.05.076.
Magnotti, G., Geyer, D., & Barlow, R. S. Interference free spontaneous Raman spectroscopy for measurements in rich hydrocarbon flames. United States. doi:10.1016/j.proci.2014.05.076.
Magnotti, G., Geyer, D., and Barlow, R. S. 2015. "Interference free spontaneous Raman spectroscopy for measurements in rich hydrocarbon flames". United States. doi:10.1016/j.proci.2014.05.076.
title = {Interference free spontaneous Raman spectroscopy for measurements in rich hydrocarbon flames},
author = {Magnotti, G. and Geyer, D. and Barlow, R. S.},
abstractNote = {},
doi = {10.1016/j.proci.2014.05.076},
journal = {Proceedings of the Combustion Institute},
number = 3,
volume = 35,
place = {United States},
year = 2015,
month = 1

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.proci.2014.05.076

Citation Metrics:
Cited by: 5works
Citation information provided by
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  • Cited by 1
  • What appears to be fluorescence has been measured in the blue (visibly soot free) regions of laminar and turbulent nonpremixed flames of methane at atmospheric pressure. The measurements are part of an experiment to measure the spontaneous Raman scattering of eight species in the flame. The flames studied range from ones with low mixing rates to flames close to extinction. The ''fluorescence'' is nonresonantly excited by a pulsed dye laser and has been routinely monitored at lambda = 516.5 nm which is a bandhead of diatomic carbon, C/sub 2/. It is Stokes ''fluorescence'' that interferes with the Raman signal detection.more » It is found that the ''fluorescence'' is broadband covering all the visible spectrum, and is observed only on the rich side of stoichiometry with noticeable intensities for fuel number densities in the range 0.1 to approx. = 1.5 x 10/sup 18/ cm/sup -3/. The ''fluorescence'' intensity is of the order of the Raman signals, increases with the fourth power of the laser flux, is unaffected by flame stretch, and decreases with dilution of the unburned methane. No ''fluorescence'' is detected at temperatures below approx. = 1000/sup 0/C.« less
  • Dual-broadband rotational coherent anti-Stokes Raman spectroscopy (DB-RCARS) has been investigated for thermometry under high-pressure and high-temperature conditions, in the product gas of fuel-lean hydrocarbon flames up to 1 MPa. Initial calibration measurements made in nitrogen, oxygen, and air, at pressures up to 1.55 MPa and temperatures up to 1800 K, showed good agreement between experimental and theoretical spectra. In the high-pressure flames, high-quality single-shot spectra were recorded in which nitrogen lines dominated, and peaks from CO{sub 2} and O{sub 2} were also visible. A spectral model including the species N{sub 2}, CO{sub 2}, and O{sub 2}, as well as themore » best available Raman linewidth models for flame thermometry, were used to evaluate the experimental spectra. Experimental problems as well as considerations related to the spectral evaluation are discussed. This work demonstrates the significant potential of DB-RCARS thermometry for applications in high-pressure and high-temperature environments. (author)« less
  • Temperature fluctuations have been measured in a turbulent, natural gas-fueled, piloted jet diffusion flame with a fuel jet exit Reynolds number of 9,700, using broadband Coherent Anti-Stokes Raman Spectroscopy (CARS) nitrogen thermometry with a best spatial resolution of 0.9 mm. Radial profiles of mean temperature and root mean square (rms) temperature fluctuations have been acquired and temperature probability density functions (pdfs) have been constructed for streamwide distances in the range 4.2 {le} x/d {le} 66.7. Comparison with thermocouple measurements shows very good agreement in regions of moderate temperature gradients, whereas in the steeper gradient jet flank areas spatial averaging leadsmore » to CARS mean temperatures lower by as much as 60 K for x/d {ge} 25 and by 150 K for x/d = 8.3. Comparison with numerical predictions that employ a {kappa}-{epsilon} model for turbulence and a constrained equilibrium model for chemistry along with a presumed pdf shape for the mixture fraction, shows very good agreement, for x/d {ge} 16.7, between computed and measured peak and centerline mean temperatures and rms temperature fluctuations, and fair agreement for x/d = 8.3. The thermal jet widths are underpredicted for x/d {ge} 25. Measured pdfs attain a variety of shapes, from nearly symmetric around the centerline and bimodal near the average reaction zone location, to nearly uniform in parts of the jet flanks and, finally, to triangular at the jet tails. In addition, measured centerline pdfs evolve from triangular to nearly Gaussian as x/d increases. The agreement between predicted and measured pdf shapes is excellent at the centerline and is very good in other parts of the jet flame.« less
  • This paper reports on coherent anti-Stokes Raman spectroscopy (CARS) which is a laser diagnostic technique that can be used to determine temperature and major species concentrations in harsh combustion environments. CARS has been successfully applied to clean gas flames, but much less attention has been given to particle-laden flames like those encountered in industrial coal burners. Typically, experimental CARS spectra are obtained from a flame and then compared with theoretical CARS spectra to determine temperature and species concentration information. This information is more difficult to acquire in coal flames due to background and nonresonant interferences. These interferences alter the shapemore » and intensity of the CARS signal, thus making analysis with unmodified version of standard CARS fitting codes impractical. Nitrogen temperature measurements were obtained in heavily coal-seeded natural gas/air flames two different coals and several coal feed rates and stoichiometries were investigated in order to determine possible limits associated with making CARS measurements in coal flames.« less