Effects of metamaterial coatings on radiative heat transfer and infrared radiation characteristics for aero-engine exhaust systems

Conventional low-emissivity coatings have been widely employed to suppress the infrared radiation (IR) of aero-engine exhaust systems, serving as a key measure to enhance aircraft survivability against infrared detection. Based on the atmospheric transmission characteristics in the infrared band, a spectrally selective metamaterial coating was designed using full-wave simulations to precisely match its emissivity with the atmospheric absorption. The coating is then applied to the IR suppression of aero-engine exhaust systems, and its effects on both radiative heat transfer and IR characteristics are evaluated using the Reverse Monte Carlo Method (RMCM). The coating properties are directly assigned to the wall mesh cells and evaluated through ray tracing method. Three coating configurations are considered: uncoated, coated with a low-emissivity coating, and coated with the metamaterial coating. Compared with the low-emissivity coating, the metamaterial coating increases radiative heat flux by 46.8% and reduces wall temperature by up to 33 K. When atmospheric transmission is considered, the IR intensity of the metamaterial-coated scheme remains consistently lower than that of the low-emissivity scheme as detection distance increases, reaching a reduction of 19.61% at 100 km. Results demonstrate that the metamaterial coating achieves infrared suppression performance superior to that of low-emissivity coatings, while effectively mitigating the heat accumulation typically induced by traditional coatings. This work, through numerical simulation, provides a novel material solution and a reliable theoretical foundation for advancing infrared suppression technology in aero-engine exhaust systems.