Comparison of UV Absorption Measurements with Probe-Sampling Measurements of Nitric Oxide Concentration in a Jet Engine Combustor Exhaust
Final rept. 1 Apr-1 Jul 1975
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
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Measurements were made in the exhaust of a T-56 turbine engine combustor of nitric oxide NO concentration using an ultraviolet UV spectral absorption technique. The measurements were made at two axial locations in the combustor exhaust stream. The NO gamma-band radiation at 2265 A produced in a resonance source was passed through the exhaust stream, and the amount transmitted was recorded. The mathematical model used to determine the NO concentration from the absorption measurements is described. Pressure and temperature broadening effects on the measured absorption are considered in the line-by-line transmission calculation. The line-of-sight absorption measurements through the axisymmetric exhaust stream were converted to local concentration values via an iterative radial inversion computation. These in situ measurements are compared to NO concentration values obtained by conventional probe-sampling techniques using a chemiluminescent analyzer. The in situ measurements of the NO concentration were larger than the probe-sampled measurements by from 50 to 80 percent, depending upon the measurement location in the exhaust stream.
- Test Facilities, Equipment and Methods
- Atomic and Molecular Physics and Spectroscopy
- Jet and Gas Turbine Engines