Measurement of Aircraft Turbine Engine Exhaust Emissions
This paper describes a current program to demonstrate the use of laser Raman backscattering as a means to measure the composition and temperature of aircraft engine exhaust emissions. The physical characteristics of turbine exhausts that most significantly influence Raman spectroscopic analysis are the relatively low pollutant concentrations in combination with elevated temperatures such that significant upper level excitations can occur with subsequent broadening and overlapping of the Raman spectra. We discuss the effects of these characteristics regarding quantitative gas analysis by Raman scattering at elevated temperatures. An experimental lidar unit was constructed using a 0.5 watt average power 3371 A pulsed nitrogen laser, a 24-inch diameter Dall-Kirkham Cassegrainian-type receiver telescope and a 1 meter, double scanning spectrometer for spectral analysis. The entire system operation is controlled by computer, including calibration, data collection and data analysis. Preliminary experimental results will be presented.
KeywordsNitric Oxide Pulse Nitrogen Laser Turbine Exhaust Dipole Interaction Energy Engine Exhaust Emission
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