IR signature characteristics of a turbine engine plume with a 2D nozzle

Suppression of Infrared (IR) signatures from exhaust plume through specialized nozzles is widely employed to minimize vulnerability to IR-guided systems. To quantitatively assess the effect of the 2D nozzle on IR suppression, the IR signatures of exhaust plume for conventional circular and 2D nozzles were measured across various spectral ranges and observation angles. The results showed that the 2D nozzle exhibited attenuated IR signatures compared to the circular nozzle across most spectral ranges and observation angles. In particular, the integrated intensity in the MWIR range, which is the main spectral range for IR seeker detection, was reduced by up to 67% and 89% for the 2D nozzle in horizontal and vertical direction, respectively. The reason was discovered from the thermo-fluidic analysis that 2D nozzle enhanced mixing between exhaust plume and ambient air, significantly reducing the plume core and the IR signature.