• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.7
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• pp.626-634
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• 2015

In the present study, numerical predictions of infrared spectra for $CO_2$ molecule were conducted. Absorption coefficients of $CO_2$ which are required for simulating the spectra, were calculated by using a line-by-line method and by adopting spectroscopic parameters from the radiation databases, HITEMP2010 and CDSD-4000. Simulations were made in the 2.7, 4.3, and $15{\mu}m$ band regions, and the results were compared with the measurements of other researchers. It was found that the calculated results are well matched with the various measurements. However, in the $4.3{\mu}m$ band region, the CDSD-4000 based calculation yields a better fit to the measurement than the HITEMP2010 based calculation does.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.7
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• pp.568-575
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• 2016

For the combat survivability, an infrared signature emitted from aircraft is needed to be predicted and analyzed. In this study, we studied the infrared signature from the exhaust plume from the viewpoint of Infrared(IR) detector. The Line-By-Line method using the radiation database is used for radiative property, and radiative intensity analysis is conducted along 1-D line of sight based on the radiative property. The numerical thermo-fluid field for the plume is conducted by ANSYS FLUENT, while setting the lines of sight having the different detection angle on the thermo-fluid field. We found the high IR signature on the line of sight passing through the locally high temperature region of the plume inside, and the strongest signature from the line of sight toward the nozzle surface. Based on this, it confirms the influence of the surface radiative emission on the infrared signature.