Turbofan

About: Turbofan is a research topic. Over the lifetime, 4114 publications have been published within this topic receiving 39490 citations. The topic is also known as: fanjet & turbofan engine.

Shape memory alloy actuation for a variable area fan nozzle

Abstract: The ability to control fan nozzle exit area is an enabling technology for next generation high-bypass-ratio turbofan engines. Performance benefits for such designs are estimated at up to 9% in thrust specific fuel consumption (TSFC) relative to current fixed-geometry engines. Conventionally actuated variable area fan nozzle (VAN) concepts tend to be heavy and complicated, with significant aircraft integration, reliability and packaging issues. The goal of this effort was to eliminate these undesirable features and formulate a design that meets or exceeds leakage, durability, reliability, maintenance and manufacturing cost goals. A Shape Memory Alloy (SMA) bundled cable actuator acting to move an array of flaps around the fan nozzle annulus is a concept that meets these requirements. The SMA bundled cable actuator developed by the United Technologies Corporation (Patents Pending) provides significant work output (greater than 2200 in-lb per flap, through the range of motion) in a compact package and minimizes system complexity. Results of a detailed design study indicate substantial engine performance, weight, and range benefits. The SMA- based actuation system is roughly two times lighter than a conventional mechanical system, with significant aircraft direct operating cost savings (2-3%) and range improvements (5-6%) relative to a fixed-geometry nozzle geared turbofan. A full-scale sector model of this VAN system was built and then tested at the Jet Exit Test Facility at NASA Langley to demonstrate the system's ability to achieve 20% area variation of the nozzle under full scale aerodynamic loads. The actuator exceeded requirements, achieving repeated actuation against full-scale loads representative of typical cruise as well as greater than worst-case (ultimate) aerodynamic conditions. Based on these encouraging results, work is continuing with the goal of a flight test on a C-17 transport aircraft.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Compact booster bleed turbofan

Abstract: A turbofan engine (10) includes a fan (14) mounted to a fan frame (32) inside a fan nacelle (30). A booster compressor (16) is joined to the fan (14) inboard a flow splitter (34). A booster bleed system (54) is disposed inside the splitter (34), and includes an inlet (58) at the compressor outlet (52), and an outlet (60) joined to the bypass duct (36) following the fan (14).

Two-stage mixer ejector suppressor

Abstract: A two-stage mixer ejector concept ("TSMEC") is disclosed for suppressing the noise emanated by jet aircraft. This TSMEC was designed to help older engines meet the stringent new federal noise regulations, known as "Stage III". In an illustrated embodiment, the TSMEC comprises: a lobed engine nozzle attached to the rear of a turbofan engine; a short shroud that straddles the exit end of the engine nozzle; two rings of convergent/divergent primary and secondary lobes within the engine nozzle shroud and; and a ring of arcuate gaps that precede the shroud and the second nozzle ring. The lobes are complimentary shaped to rapidly mix the turbine's hot exhaust flow with cooler air including entrained ambient air, at supersonic speed. This drastically reduces the jet exhaust's velocity and increases jet mixing, thereby reducing the jet noise.

A computer program for calculating design and off-design performance for turbojet and turbofan engines

Abstract: Program uses component performance maps to enable user to do analytical engine cycle calculations. Through scaling procedure, each of the component maps can be used to represent a family of maps. Either convergent or convergent-divergent nozzles may be used.

Exergy analysis of a turbofan aircraft engine

Abstract: An exergy analysis is reported for a General Electric turbofan engine (the CF6-80) using sea-level data. The effects on exergy efficiencies and exergy destructions are investigated of modifying the isentropic efficiencies of turbomachinery components. The most irreversible units in the system are found to be the fan and the core engine exhaust, with exergy loss rates of 47.3 MW and 35.9 MW, respectively, and the combustion chamber, with an exergy destruction rate of 31.5 MW. The exergy efficiencies of the fan and the core engine exhausts are found to be 12.9 and 12.7%, respectively.