Research on the influence of combustion and emission characteristics on infrared radiation characteristics of spherical convergent vector nozzle

The rear infrared radiation intensity of an aero-engine is dominated by infrared-active CO 2 , CO and H 2 O in combustion products. To explore how fuel emission traits affect exhaust infrared radiation, this study adopts a spherical convergent vectoring nozzle as the research model. By combining simplified chemical reaction mechanisms with the Reverse Monte Carlo Method, numerical simulations of rear infrared radiation are carried out for multiple aviation fuels at different equivalence ratios. Fuel type and equivalence ratio exert prominent coupled impacts on radiation features. RP-3 and JP-8 display comparable performance. JET-A yields the highest CO 2 and H 2 O concentrations, while JP-10 owns a larger CO mass fraction under fuel-rich combustion. Fuel differences mainly affect lateral and large-angle integrated radiation, where JP-10 delivers the strongest radiation and JET-A the weakest. Growing equivalence ratios shift radiation peaks from the tail-on direction to lateral sides, greatly lifting large-angle and total radiation intensity. Spectrum analysis shows rich-fuel combustion forms unique W/M-shaped spectral profiles in the 4.2–5.0 μm band, with spectral peaks intensifying as equivalence ratios increase.