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- Vestin, Fredrik, et al.
(författare)
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Development of rotational CARS for combustion diagnostics using a polarization approach
- 2007
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1873-2704 .- 1540-7489. ; 31 I, s. 833-840
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Konferensbidrag (refereegranskat)abstract
- Rotational Coherent anti-Stokes Raman spectroscopy (CARS) has the last decades been developed into a useful tool for thermometry and concentration measurements in combustion. In this paper, we present a novel polarization approach of the technique, which will enhance its potential and widen the range of conditions at which it can be utilized. The theory of the polarization approach is described in detail. It is shown that by specific arrangement of the polarizations of the laser beams, total suppression of the non-resonant background signal can be obtained, and thus by probing only the resonant CARS signal the diagnostic utility of the technique increases. The main benefit of the approach is in situations where the non-resonant background signal is relatively high in comparison with the resonant signal. The high potential of polarization rotational CARS for thermometry is demonstrated in some illustrative examples, for example, nitrogen thermometry on the fuel side of diffusion flames, and carbon monoxide thermometry in the product gas of ethylene/oxygen/argon-flames. © 2006 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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| 2. |
- Vestin, Fredrik, et al.
(författare)
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Rotational CARS thermometry at high temperature (1800 K) and high pressure (0.1-1.55 MPa)
- 2007
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Ingår i: Journal of Raman Spectroscopy. - : Wiley. - 1097-4555 .- 0377-0486. ; 38:8, s. 963-968
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Tidskriftsartikel (refereegranskat)abstract
- Dual-broadband rotational CARS (DB-RCARS) thermometry has been investigated at high temperature and high pressure. Single-shot measurements were performed at 1800 K, in air and nitrogen at pressures up to 1.55 MPa and in oxygen at pressures up to 0.5 MPa. For all conditions, the resonant signal contribution to the spectra clearly dominated over the non-resonant one, implying the high potential for DB-RCARS for temperature and concentration measurements also at the high temperatures and pressures used in the present investigation. The relative standard deviation was generally similar to 2% for single-shot data at pressures from 0.5 to 1.55 MPa. At the investigated temperature, 1800 K, rotational lines from thermally excited vibrational states could be observed in the highly resolved experimental spectra. Using a previously developed weighting procedure applied to these lines, it was demonstrated that the temperature standard deviation could be lowered with as much as 30%.
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