Selecting the right duct for stealth of plane from view of thermal radar

Abstract In this study, Ducts is designed for decrease infrared radiation effect of plane plume. These ducts have circular inlet and ellipse exit. The Cooling of hot plane plume is done by designed ducts to reduce the radar visibility and hence stealth. For this purpose, ellipse exit cause to elongation of flow to wings direction and cooling of hot plume. Simulation is done by ANSYS Fluent 2015 program by usind different turbulence models, but finally used k-ε RNG model with 12 million meshes. Ducts designed with aspect ratio of 2.5, 4.5, 6.5 and 8.5. Intercept range of thermal radar in different duct elevation angle with aspect ratio of 2.5, 4.5, 6.5 and 8.5 is decreased to 14, 19, 28 and 34 percent respectively. Finally, by studying the results of the sequence luminance and the flow thrust, the duct was selected with an aspect ratio of 5.6 as the optimum duct. Keywords Duct, Infrared radiation effect, thermal radar, plume, radiation