Imaging Fourier transform spectrometry of jet engine exhaust with the telops FIRST-MWE

The Field-portable Imaging Radiometric Spectrometer Technology Midwave Extended (FIRST-MWE) system developed by Telops, Inc. was used to capture hyperspectral imagery of turbojet engine exhaust. The FIRST-MWE is a Michelson interferometer coupled to a 320 times 256 Indium Antimonide (InSb) focal plane array with instantaneous field of view (IFOV) of 0.35 mrad. Exhaust from a diesel-fueled Turbine Technologies, Ltd. SR-30 turbojet engine was imaged at three modes of operation from a side-plume vantage point close to the engine. Temporally-averaged spectral data featured strong CO₂ emission near 2200-2450 cm^-1. A simple radiative transfer model was used to produce spatially-resolved maps of the temperature and relative CO₂ concentration. The model assumed an optically-thin plume that was homogeneous along each pixel's line-of-sight. The Carbon Dioxide Spectroscopic Databank was used to compute molecular cross-sections used in fitting the temporally-averaged spectra.