The present invention relates generally to gas turbine engines, and more specifically to a method and apparatus for suppressing the infrared signature of a gas turbine engine.
Gas turbine engines typically include a compressor, a combustor, and a turbine section. Airflow entering the compressor is compressed and channeled to the combustor, wherein air is mixed with a fuel and ignited within a combustion chamber to produce combustion gases. The combustion gases are channeled to the turbine section that extracts energy from the combustion gases for powering the compressor. The turbine section may include two independent turbines. One turbine extracts energy from the combustion gases to power the compressor. The other turbine may be used to power an output shaft connected to a load, such as a fan, an electrical generator, or a helicopter rotor. The combustion gases exiting the turbine(s) are discharged from the engine through an engine exhaust.
A growing importance within the field of weapons detection technology is reducing the infrared signature associated with gas turbine engines used to power military aircraft and land combat vehicles. Signature reductions may reduce detection and pursuit by enemy anti-aircraft equipment such as heat-seeking missiles. Some known systems for suppressing infrared radiation signatures from gas turbine engines use a center plug positioned within the engine exhaust to block line of sight to hot turbine parts of the engine. Other known systems eject hot exhaust gases at a substantial angle from an axial centerline of the engine to reduce the infrared signature of the engine. However, such known suppression systems may have size and weight disadvantages, in addition to possible installation penalties in engine performance.
Additionally, due to associated performance penalties it may be undesirable to use infrared suppression systems when an aircraft or vehicle is operating under non-combat conditions. Accordingly, some known infrared suppression systems are removed from the aircraft or vehicle when the aircraft or vehicle is operating under non-combat conditions. However, removing infrared suppression systems from aircraft/vehicles may be difficult and time-consuming.