Laser Raman gas thermometry
Abstract
A laser Raman thermometric technique is described which permits remote temperature sensing in combustor environments by monitoring N2 vibrational Raman scattering induced by a pulsed dye laser. Temperature is inferred from the ratio of the vibrational anti-Stokes and Stokes scattering signatures. Due to the large energy exchange which accompanies vibrational scattering, the scattered intensities are well-displaced spectrally from the exciting beam permitting the use of narrow-band interference filters for signal separation rather than the dispersive instrumentation commonly employed. To permit greater experimental versatility, the scattering is collected coaxial to the laser input, thus necessitating only a single probing aperture. A two-channel Raman spectrometer is described which houses the coaxial transceiver, interference filters and photomultipliers which monitor the scattered intensities. The scattering signatures are subsequently processed and averaged to yield temperature information. Temperature determinations in a hydrocarbon flame are presented together with a discussion of the technique's capability.
- Publication:
-
American Institute of Aeronautics and Astronautics and Society of Automotive Engineers, Propulsion Conference, 10th
- Pub Date:
- October 1974
- Bibcode:
- 1974auep.conf.....E
- Keywords:
-
- Gas Temperature;
- Laser Applications;
- Light Scattering;
- Raman Spectra;
- Temperature Measurement;
- Combustion Chambers;
- Dye Lasers;
- Error Analysis;
- Optical Measuring Instruments;
- Pulsed Lasers;
- Remote Sensors;
- Instrumentation and Photography