Interferometric flame temperature probe using the rotational Raman spectrum of nitrogen
A flat-flame is produced on a porous-plug burner. The spontaneous rotational Raman emission of nitrogen is used to determine the temperature of different positions within the flame. The Raman emission is passed through a Fabry-Perot interferometer. The free spectral range of the FPI is set to match the separation of the rotational Raman lines of the nitrogen molecule. This allows the lines to pass through the interferometer simultaneously to produce a multiplexing effect with a resultant gain in intensity. The shape of the interferogram is dependent on the temperature of the scattering molecule. The output of the interferometer was passed through a monochrometer to filter out as much of the flame emission as possible before detection with a photomultiplier tube set up in a photon counting mode. The photons were counted with a multichannel analyzer and the resulting interferogram fit to theoretical interferograms. It was found that the fit temperatures agreed reasonably well with thermocouple measurements made at the same positions within the flame. The resulting temperature profiles resembled profiles reported in the literature and the errors were of the same order of magnitude obtained by other researchers.
- OSTI ID:
- 6561638
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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