항공기 Serration 형상 노즐의 열유동장과 피탐지성에 관한 전산해석

Abstract

In this study, by applying a serration shape to the exhaust nozzle of an aircraft, the thermal flow field, infrared, and radar cross-section signals were analyzed through computational analysis, and the effect on observability was studied. The length and number of serration shapes were selected as the design variables of the nozzle and the weight change was kept minimal. The temperature distribution and the turbulence kinetic energy of the thermal flow field were examined, and the mixing tendency due to nozzle deformation was compared for each section. The infrared signal was then calculated based on the thermal flow field data. The average infrared radiance value of the serrated nozzles decreased by up to 10.4% compared to the circular shape. Monostatic radar cross-section was calculated for the 10 GHz frequency for the electromagnetic wave analysis, and its effect on the azimuth angle was analyzed. When the serration shape was applied, it turned out that the average radar cross-section value was reduced by up to 7.4%. Overall, the exhaust plume flow was diffused and the infrared and radar cross-section signals were reduced for the serrated nozzles.