Experimental Investigation on Infrared Signatures of Axisymmetric Vectoring Exhaust Nozzle With Film Cooling and Low-Emissivity Coating

Investigations on infrared (IR) radiation suppression of axisymmetric vectoring exhaust nozzle (AVEN) are meaningful, due to the requests for maneuverability and IR stealth capability of aircrafts. In this paper, the synthetic suppression scheme of film cooling and low-emissivity coating was adopted on the center body and divergent flaps of the nozzles at 0 deg, 10 deg, and 20 deg vectoring angles. The IR signatures of both the baseline AVEN and the nozzles with IR suppression were measured. Comparing the IR signatures of the nozzles with and without IR suppression measures, the IR suppression effectiveness of the film cooling and low-emissivity coating was obtained. The investigation results indicate that the IR signatures of AVEN decrease with the increase of vectoring angle. The film cooling enables a remarkable decrease of the IR signatures of AVEN. The synthetic suppression of film cooling and low-emissivity coating enables a further decrease of IR signatures. For the case studied in this paper, the integrated radiation intensities of the nozzles with film cooling and low-emissivity coating at 0 deg, 10 deg, and 20 deg vectoring angles are decreased by 52.3%, 57.9%, and 37.2% at 0 deg measurement angle, respectively.