In modern international situation, many countries make an effort to strengthen their national defense. Above all, aircraft with stealth technology in modern battle field is essential to improve the aircraft survivability, because, IR guided missile and detector of enemy forces threaten aircraft safety. Also, the exhaust plume with high temperature can heat the base plane of the aircraft, and enhance the IR signature from the aircraft body. To resolve this problem, IR signature reduction technologies from both aircraft and exhaust plumes are necessary. Although the advanced country lead the survivability research of aircraft, they strongly control the outflow of this technology overseas. Therefore, investigation of the IR signature and aircraft base heating from exhaust plume is highly required.
In this study, investigations on IR signatures and radiative base heating characteristics from aircraft exhaust plumes are conducted using a pre-conditioning method for plume thermal flow and NB based WSGGM coupled with FVM for radiative heat transfer. In the following, a model description and mathematical formulations are introduced to attack the flow field and radiative characteristics in aircraft exhaust plumes. Also IR signatures at ground detector are analyzed by considering the atmospheric effect such as transmissivity due to atmospheric CO2 and H2O by using the LOWTRAN 7 which is one of the atmospheric propagation analysis program. After validating present solutions by comparing with those obtained in the literature, IRSL in the plume and amounts of radiative base heating due to searchlight and plume emissions for subsonic aircraft are examined with two different altitude conditions. The results show that the radiative heat flux coming into the base plane decreases with altitude and distance, but it increases with the particle temperature. The forward scattering of particles increases PE while it decreases SE. Also, it is found that the particular wavelength IR signature has high spectral characteristics because of H2O and CO2 gases in the plume. and the IR signature captured by the ground detector shows high blue and red spikes near 4.3 band due to CO2 in the atmosphere. Also, at IR signature from the ground observation angle of 60°, the lowest in the case was expected. Also, the lowest IR signature is captured when the ground observation angle is 60° among all the Case considered in this work.