Incidence angle-dependent aerodynamic loss characteristics of rearward full-obstruction turbine outlet guide vanes

This paper proposes a novel rearward full-obstruction turbine outlet guide vane (RF-OGV) configuration for infrared stealth enhancement in aero-engine exhaust systems. The proposed method achieves complete optical shielding of hot low-pressure turbine blades to suppress backward-directed infrared emissions, while simultaneously rectifying turbine-exit swirl distortion. Aerodynamic performance was systematically evaluated through variable incidence cascade experiments (±15°) under engine-representative Mach conditions. The fundamental flow loss mechanisms of the RF-OGV were synergistically analyzed with computational fluid dynamics. The results indicate that the flow inside the RF-OGV exhibits a “favorable-to-adverse” pressure gradient sequence, accompanied by visible surface flow separation. As the incidence angle increases, the total pressure loss (TPL) coefficient shows a trend of initially decreasing and then increasing, with the minimum TPL of 0.025 occurring at −5° incidence angle. Loss decomposition analysis identifies profile/wake interactions as primary contributors under negative incidence, while positive incidence elevates the end wall secondary losses.