Rotational Coherent Anti-Stokes Raman Spectroscopy: Experimental and Theoretical Developments in Gas-phase Thermometry
(2004)- Abstract
- Dual-broadband pure rotational coherent anti-Stokes Raman spectroscopy was investigated in terms of thermometry and species concentration measurement for studies of combustion.
The modelling of rotational CARS spectra under conditions of high pressure at room temperature was investigated. Resonant terms of the Stokes (CSRS) type were found to have a significant effect on the intensity of the anti-Stokes (CARS) branch, the effect increasing in strength with an increase in pressure. Taking account of this inter-branch interference effect improved the accuracy of temperature measurement under conditions of high pressure.
An experimental study of the statistical precision of temperature measurements showed... (More) - Dual-broadband pure rotational coherent anti-Stokes Raman spectroscopy was investigated in terms of thermometry and species concentration measurement for studies of combustion.
The modelling of rotational CARS spectra under conditions of high pressure at room temperature was investigated. Resonant terms of the Stokes (CSRS) type were found to have a significant effect on the intensity of the anti-Stokes (CARS) branch, the effect increasing in strength with an increase in pressure. Taking account of this inter-branch interference effect improved the accuracy of temperature measurement under conditions of high pressure.
An experimental study of the statistical precision of temperature measurements showed the precision to improve with use of a single-mode rather than a multi-mode Nd:YAG laser, a decrease in standard deviation by a factor of two or more being observed. Further investigation linked the measurement precision to the intensity noise observed in the CARS spectra.
Temperature measurements in the post-flame zone of ethylene/air flames were conducted with the aim of studying the impact on temperature measurements of the collisional line widths employed in the model. Taking account of the line broadening of the species CO, CO<sub>2</sub> and H<sub>2</sub>O was found to increase the evaluated temperature by 20-47 K. Spectra recorded in ethylene/air flames revealed the spectral signatures of N<sub>2</sub>, O<sub>2</sub>, CO and CO<sub>2</sub>, the spectrum of nitrogen always being strongest. The potential of rotational CARS for species concentration measurements under such conditions was also investigated. A model for binary mixtures of N<sub>2</sub> and CO that was developed was tested for concentration measurements in these flames. The measured CO concentrations agreed closely with theoretical calculations.
The collisional line broadening of Raman spectral lines in mixtures of N<sub>2</sub> and CO was studied theoretically by means of semiclassical Robert-Bonamy calculations. The self-broadening of nitrogen (N<sub>2</sub>-N<sub>2</sub>) in particular was investigated, employing the ab initio intermolecular potential PES8. The major objective was to calculate CO-N<sub>2</sub> and N<sub>2</sub>-CO line broadening. Use of the line widths obtained resulted in more accurate CO concentration measurements in binary mixtures of CO and N<sub>2</sub> by use of rotational CARS. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/467224
- author
- Afzelius, Mikael LU
- supervisor
- opponent
-
- Professor Ewart, Paul, University of Oxford, United Kingdom
- organization
- publishing date
- 2004
- type
- Thesis
- publication status
- published
- subject
- keywords
- collision line-broadening calculations, combustion laser diagnostics, Laserteknik, Laser technology, CARS, coherent laser spectroscopy, Fysicumarkivet A:2004:Afzelius
- pages
- 230 pages
- publisher
- Division of Combustion Physics, Department of Physics, Lund University
- defense location
- Fysiska Institutionen, Professorsgatan 1, Hörsal B, Lunds Tekniska Högskola.
- defense date
- 2004-09-03 10:15:00
- external identifiers
-
- other:ISRN:LUTFD2/TFCP--94--SE
- ISBN
- 91-628-6179-4
- language
- English
- LU publication?
- yes
- additional info
- Article: I. M. Afzelius and P.-E. Bengtsson, Dual-broadband rotational CARS modelling of nitrogen at pressures up to 9 MPa. I. Inter-branch interference effect, Appl. Phys. B 75, 763-769 (2002) Article: II. M. Afzelius, P.-E. Bengtsson, J. Bood, J. Bonamy, F. Chaussard, H. Berger, and T. Dreier, Dual-broadband rotational CARS modelling of nitrogen at pressures up to 9 MPa. II. Rotational Raman line widths, Appl. Phys. B 75, 771-778 (2002) Article: III. M. Afzelius and P.-E. Bengtsson, Precision of single-shot dual-broadband rotational CARS thermometry with single-mode and multi-mode Nd:YAG lasers, J. Raman Spectrosc. 34, 940-945 (2003) Article: IV. F. Vestin, M. Afzelius, C. Brackmann, and P.-E. Bengtsson, Dual-broadband rotational CARS thermometry in the product gas of hydrocarbons flames, Accepted for publication in the proceedings of the 30th International Symposium on Combustion Article: V. M. Afzelius, C. Brackmann, and P.-E. Bengtsson, Pure rotational coherent Anti-Stokes Raman spectroscopy in mixtures of CO and N2, Submitted to Appl. Opt. Article: VI. C. Brackmann, J. Bood, M. Afzelius, and P.-E. Bengtsson, Review Article: Thermometry in internal combustion engines via dual-broadband rotational coherent anti-Stokes Raman spectroscopy, Meas. Sci. Technol. 15, R13-R25 (2004) Article: VII. M. Afzelius, P.-E. Bengtsson, and J. Bonamy, Semiclassical calculations of collision line broadening in Raman spectra of N2 and CO mixtures, J. Chem. Phys. 120, 8616-8623 (2004) Article: VIII. M. Afzelius, J. Buldyreva, and J. Bonamy, Exact treatment of classical trajectories governed by an isotropic potential for linewidth computations, Accepted for publication by Mol. Phys.
- id
- 353e16b1-bf43-4782-ae1f-fd3f2ffd3213 (old id 467224)
- date added to LUP
- 2016-04-01 16:53:42
- date last changed
- 2018-11-21 20:45:02
@phdthesis{353e16b1-bf43-4782-ae1f-fd3f2ffd3213,
abstract = {{Dual-broadband pure rotational coherent anti-Stokes Raman spectroscopy was investigated in terms of thermometry and species concentration measurement for studies of combustion.<br/><br>
<br/><br>
The modelling of rotational CARS spectra under conditions of high pressure at room temperature was investigated. Resonant terms of the Stokes (CSRS) type were found to have a significant effect on the intensity of the anti-Stokes (CARS) branch, the effect increasing in strength with an increase in pressure. Taking account of this inter-branch interference effect improved the accuracy of temperature measurement under conditions of high pressure.<br/><br>
<br/><br>
An experimental study of the statistical precision of temperature measurements showed the precision to improve with use of a single-mode rather than a multi-mode Nd:YAG laser, a decrease in standard deviation by a factor of two or more being observed. Further investigation linked the measurement precision to the intensity noise observed in the CARS spectra.<br/><br>
<br/><br>
Temperature measurements in the post-flame zone of ethylene/air flames were conducted with the aim of studying the impact on temperature measurements of the collisional line widths employed in the model. Taking account of the line broadening of the species CO, CO<sub>2</sub> and H<sub>2</sub>O was found to increase the evaluated temperature by 20-47 K. Spectra recorded in ethylene/air flames revealed the spectral signatures of N<sub>2</sub>, O<sub>2</sub>, CO and CO<sub>2</sub>, the spectrum of nitrogen always being strongest. The potential of rotational CARS for species concentration measurements under such conditions was also investigated. A model for binary mixtures of N<sub>2</sub> and CO that was developed was tested for concentration measurements in these flames. The measured CO concentrations agreed closely with theoretical calculations.<br/><br>
<br/><br>
The collisional line broadening of Raman spectral lines in mixtures of N<sub>2</sub> and CO was studied theoretically by means of semiclassical Robert-Bonamy calculations. The self-broadening of nitrogen (N<sub>2</sub>-N<sub>2</sub>) in particular was investigated, employing the ab initio intermolecular potential PES8. The major objective was to calculate CO-N<sub>2</sub> and N<sub>2</sub>-CO line broadening. Use of the line widths obtained resulted in more accurate CO concentration measurements in binary mixtures of CO and N<sub>2</sub> by use of rotational CARS.}},
author = {{Afzelius, Mikael}},
isbn = {{91-628-6179-4}},
keywords = {{collision line-broadening calculations; combustion laser diagnostics; Laserteknik; Laser technology; CARS; coherent laser spectroscopy; Fysicumarkivet A:2004:Afzelius}},
language = {{eng}},
publisher = {{Division of Combustion Physics, Department of Physics, Lund University}},
school = {{Lund University}},
title = {{Rotational Coherent Anti-Stokes Raman Spectroscopy: Experimental and Theoretical Developments in Gas-phase Thermometry}},
year = {{2004}},
}