Title: Measurement of temperature gradients through local extinction using Raman scattering spectroscopy

Authors: William F. Carnell Jr., Michael W. Renfro

Addresses: Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, Unit 3139, Storrs, CT 06269-3139, USA. ' Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, Unit 3139, Storrs, CT 06269-3139, USA

Abstract: Measurements of temperature in laminar flames with localised extinction points were made using line imaging of spectrally resolved laser Raman scattering through the extinction process. A fit to the nitrogen scattering spectrum was used to determine temperature with an accuracy of ±30 K. Temperature gradients through the extinction process were measured as the flame strength prior to extinction and the rate of extinction was separately controlled. The results were compared to previously reported numerical simulations for this flame and were found to validate the modelling of the flame extinction process. The measured temperature gradient is affected by the radial rate at which strain is increased, as well as inner flame strength. Measurements of integrated flame emission were also made at the extinction point and indicate that reactions persist at temperatures well below the onedimensional extinction temperature, which is consistent with reaction rate profiles from the numerical simulations.

Keywords: local flame extinction; Raman scattering spectroscopy; temperature gradients; temperature measurement; chemiluminescence emission; laminar flames; simulation; modelling; combustion.

DOI: 10.1504/IJAP.2007.013017

International Journal of Alternative Propulsion, 2007 Vol.1 No.2/3, pp.135 - 153

Published online: 03 Apr 2007 *

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