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.
|Number of pages
|Combustion and Flame
|Early online date
|6 Sept 2012
|Published - 1 Dec 2012
This work was financed by SSF (Swedish Foundation for Strategic Research) and the Swedish Energy Agency through CECOST (Centre for Combustion Science and Technology) and VR (Swedish Research Council). In addition, J.K. acknowledges support from the European Union (Large Scale Facility in Combustion and Lund Laser Centre) and from the Scottish Funding Council (SFC) through the Scottish Sensor System Centre (SSSC). Furthermore, the German Research Foundation (DFG) is acknowledged for funding SAOT in the framework of the German excellence initiative. The authors thank Ruth Hierold for technical assistance in the CARS experiments.
- laser-induced breakdown spectroscopy
- laminar flames