Investigation of infrared signature of serpentine nozzle for turbofan

Infrared stealth technology is one of the essential abilities for advanced stealth aircraft. The exhaust system is the main infrared radiation source of aircraft. The serpentine nozzle is a potential configuration that could efficiently suppress the infrared signature of the exhaust system, but there are few papers focused on the criteria for designing a serpentine nozzle from the view of infrared suppression. Investigating the effect of the shield ratio on the infrared signature of the serpentine nozzle is the primary purpose of this paper. For the serpentine nozzle, the gas infrared signature level in the vertical plane is greater than that in the horizontal plane, and the wall infrared signature level at the negative azimuth angle in the vertical plane is greater than that at the positive azimuth angle. The shield ratio has an important impact on the infrared signature of the serpentine nozzle, and the analysis indicates that the serpentine nozzle withΔY = 1 has a better stealth performance; additionally, the visible area ratio is suggested to be under 0.041.