Variable geometry gas turbine engine nacelle assembly with nanoelectromechanical system

Abstract

A nacelle assembly includes an inlet lip section and a cowl section downstream of the inlet lip section. At least a portion of the cowl section is flexed to take various shapes through a nanoelectromechanical system and thereby influence an effective boundary layer thickness of the nacelle assembly.

Description

BACKGROUND OF THE INVENTION[0001]This invention generally relates to a gas turbine engine, and more particularly to a nacelle assembly for a turbofan gas turbine engine.[0002]In an aircraft gas turbine engine, such as a turbofan engine, air is pressurized in a compressor and mixed with fuel in a combustor for generating hot combustion gases. The hot combustion gases flow downstream through turbine stages which extract energy from the hot combustion gases.[0003]Combustion gases are discharged from the turbofan engine through a core exhaust nozzle while fan air is discharged through an annular fan exhaust nozzle defined at least partially by a nacelle assembly which surrounds the core engine. A majority of propulsion thrust is provided by the pressurized fan air which is discharged through the fan exhaust nozzle, while the remaining thrust is provided from the combustion gases discharged through the core exhaust nozzle.[0004]The fan section of the turbofan engine may be geared to cont...

AI Technical Summary

Benefits of technology

[0008]A nacelle assembly includes an inlet lip section and a cowl section positioned downstream of the inlet lip section. At least a portion of the cowl section includes a flexible portion which is selectively movable to influence an effective boundary layer thickness of the nacelle assembly. A controller identifies an operability condition and selectively flexes the cowl section in response to the operability condition. The flexible portion is selectively driven by a nanoelectromechanical system

Problems solved by technology

Also, controlling the fan section tip speed allows the fan section to be of a larger diameter, which further decreases noise generation.

Although effective, a compromised “thick” inlet lip section designed for a takeoff flight condition may operate at a somewhat reduced efficiency in another flight condition, such as a cruise condition which may be better served by a “thin” inlet lip section.

Furthermore, a “thick” inlet lip section may, during some flight conditions, suffer from boundary layer separation that may decrease efficiency.

These attempts, however, have proved complex, expensive and may not fully reduce the onset of boundary layer separation.

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