Collision Widths of CO Lines Broadened by Water Vapor at Elevated Temperatures
Final rept. Jun-Sep 1982
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
Pagination or Media Count:
A non-intrusive method of measuring concentration and temperature of specific molecules in the exhaust stream of rocket and turbine engines is being sought to replace the probe methods currently being used. The probe methods being provide results which are subject to question as the probe itself may chemically alter the exhaust gas composition. The tunable diode laser TDL spectrometer system is being developed as a possible replacement for the probes. The TDL measurements can be made by passing the laser beam through the exhaust gases as they exit the engine. The energy absorbed from the laser beam is related to species concentration i.e., the absorption is proportional to the number of absorbing molecules in the beam. The absorption also depends on wavenumber line shape, as well as a line strength function which is temperature dependent. The line shape is affected by collisions with the absorbing molecules therefore, the absorption is a function of the partial pressure of each gas present. Each gas present has a characteristic effect on the shape of the absorption line. In order to make accurate measurements, the instrument should be capable of recording true line shapes.
- Atomic and Molecular Physics and Spectroscopy
- Jet and Gas Turbine Engines