Evaluation of infrared emission spectra of aircraft exhaust with the FitFas software
A Fourier transform spectrometer was used to measure infrared spectra of the exhaust gas of an aircraft's jet engine. The measured spectra were modelled by use of the program FASCODE. For this simulation, the inhomogeneous gas mixture is divided into several homogenous layers which are char...
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
1994-04-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/12/417/1994/angeo-12-417-1994.pdf |
| Summary: | A Fourier transform spectrometer was used to
measure infrared spectra of the exhaust gas of an aircraft's jet engine. The
measured spectra were modelled by use of the program FASCODE. For this
simulation, the inhomogeneous gas mixture is divided into several homogenous
layers which are characterized by their geometrical extents, temperatures,
pressures and chemical compositions. To obtain values for the temperatures and
the CO, NO, H<sub>2</sub>O and CO<sub>2</sub> concentrations of the layers a
nonlinear least-squares algorithm was implemented. The program (FITFAS) not only
changes the parameters to find the minimum of the squared differences between
measurement and calculation; it also provides the variances and covariances of
the parameters. Thus information is obtained to which parameters (besides the
interesting ones) must be fitted (or be accurately known). It also tells us
whether or not another spectral interval is more suitable for the determination
of a specific parameter. |
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| ISSN: | 0992-7689 1432-0576 |