| 1. |
- Kiefer, Johannes, et al.
(author)
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Laser-induced breakdown flame thermometry
- 2012
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In: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 159:12, s. 3576-3582
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Journal article (peer-reviewed)abstract
- The determination of temperature distribution is an essential task when flames are characterized. We propose a new approach for flame thermometry based on laser-induced breakdown spectroscopy (LIBS) utilizing the temperature dependency of the breakdown threshold laser pulse energy. Calibration measurements are carried out in heated gas flows and post-combustion gases. Compositional effects on the breakdown threshold are corrected employing a straightforward procedure. For this purpose, the elemental composition is derived from the LIBS spectra and this information is then used for correcting the measured threshold laser pulse energy. A series of proof-of-concept measurements in a laminar methane/air flame on a Bunsen burner is conducted and compared to reference data from coherent anti-Stokes Raman scattering (CARS). The corrected LIBS temperatures show excellent agreement with those obtained by CARS. Therefore, our approach represents a simple and straightforward alternative to traditionally used thermometry methods. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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| 2. |
- Kiefer, Johannes, et al.
(author)
-
Laser-induced breakdown spectroscopy : A simple but versatile tool for combustion diagnostics
- 2012
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In: Laser Applications to Chemical, Security and Environmental Analysis, LACSEA 2012. - Washington, D.C. : OSA. - 9781557529336
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Conference paper (peer-reviewed)abstract
- Laser-induced breakdown spectroscopy (LIBS) is an experimentally simple method capable of measuring elemental composition in a flame. Moreover, the breakdown threshold energy is temperature dependent. Hence, LIBS allows multiple parameter determination in combustion environments.
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| 3. |
- Kiefer, Johannes, et al.
(author)
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Local composition and temperature determination in laminar flames by laser-induced plasma diagnostics
- 2011
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In: 2011 Conference on Lasers and Electro-Optics : Laser Science to Photonic Applications, CLEO 2011 - Laser Science to Photonic Applications, CLEO 2011. - 9781557529107
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Conference paper (peer-reviewed)abstract
- We utilize laser-induced breakdown spectroscopy for measuring mixture composition and temperature in flames. Spectroscopy of the plasma emission yields concentration information, while temperature is derived from the breakdown threshold pulse energy.
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| 4. |
- Schorsch, Stefan, et al.
(author)
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Detection of Flame Radicals Using Light-Emitting Diodes
- 2010
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In: Applied Spectroscopy. - 1943-3530. ; 64:12, s. 1330-1334
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Journal article (peer-reviewed)abstract
- Lasers are common tools in the field of combustion diagnostics In some respects, however, they have disadvantages Therefore, there is a need for new light sources delivering radiation in the required wavelength regions with high stability and reliability at low cost Light-emitting diodes (LED) in the near and mid infrared spectral region have proven their potential for spectroscopic applications in the past In the present work we demonstrate the feasibility of using ultraviolet LEDs for flame diagnostics For this purpose, OH and CH radicals are detected in premixed methane/air flames The LED emission is found to be stable after thermal equilibrium is reached This was the case after a warming up period in the order of minutes The spectral characteristics were stable during a 24 h test
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