Gas turbine engine inlet with noise reduction features

Abstract

A gas turbine engine comprising a fan section, a compressor, a combustor and a turbine, includes a nacelle having an inner nacelle surface defining an inlet duct designed to reduce an inlet duct area of the inlet duct to increase acoustic attenuation. The gas turbine engine also includes a spinner, disposed forward of the fan section, that includes features to increase acoustic attenuation. In one embodiment of the present invention, the nacelle includes a nacelle contoured surface protruding radially inward from the inner nacelle surface to reduce the inlet duct area. In a further embodiment of the present invention, the spinner includes a spinner contoured surface for reducing the inlet duct area. In other embodiments, the nacelle and / or the spinner include an inflatable bladder, a SMA actuator, a fluidic actuator, or a combination thereof, selectively activated to increase acoustic attenuation during certain conditions of an aircraft.

Description

BACKGROUND OF THE INVENTION [0001] 1. Technical Field [0002] The present invention relates to gas turbine engines and, more particularly, to reduction of noise emanating therefrom. [0003] 2. Background Art [0004] In recent years, noise generated by flying aircraft has attracted attention and is now subject of various governmental regulations. Efforts need to be made to minimize annoyance to neighborhoods located in the path of departing and landing aircraft. The noise is especially disturbing during certain flight conditions such as takeoffs and landings of the aircraft. [0005] The aircraft noise is primarily generated by gas turbine engines propelling the aircraft. One major source of the noise generated by the gas turbine engine is the fan section. The fan generates tonal and broadband acoustic energy propagating outward of the engine through an inlet and through a bypass nozzle. [0006] Various considerations dictate design of the gas turbine engine that propels an aircraft. For e...

AI Technical Summary

Benefits of technology

[0007] According to the present invention, a gas turbine engine comprises a nacelle enclosing a fan section, a compressor, a combustor and a turbine, with the nacelle including an inner nacelle surface defining an inlet duct and means for reducing an inlet duct area of the inlet duct to increase acoustic attenuation during certain conditions of an aircraft. The means for reducing the inlet area is disposed on an inner nacelle surface or on a spinner, disposed forward of the fan section, or on both, the inner nacelle surface and the spinner surface.

[0008] In one embodiment of the present invention, the means for reducing the inlet area includes a nacelle contoured surface protruding radially inward from the inner nacelle surface to reduce the inlet duct area. In another embodiment of the present invention, the means for reducing the inlet area includes a spinner contoured surface protruding into the inlet duct to reduce the inlet duct area. In yet another embodiment, the means for reducing the inlet area comprises means for selectively reducing the inlet area. In a further embodiments, the means for selectively reducing the inlet area comprises an inflatable bladder, a SMA actuator, a fluidic actuator, or a combination thereof. The inflatable bladder, the SMA actuator, and the fluidic actuator are disposed on an inner nacelle surface or on a spinner, or on both, the inner nacelle surface and the spinner surface. The means for selectively reducing the inlet area may be also used in combination with the nacelle and / or spinner contoured surfaces.

[0009] The foregoing and other advantages of the present invention become more apparent in light of the following detailed description of the exemplary embodiments thereof, as illustrated in the accompanying drawings.

Problems solved by technology

In recent years, noise generated by flying aircraft has attracted attention and is now subject of various governmental regulations.

The noise is especially disturbing during certain flight conditions such as takeoffs and landings of the aircraft.

The aircraft noise is primarily generated by gas turbine engines propelling the aircraft.

One major source of the noise generated by the gas turbine engine is the fan section.

Frequently, optimization of one factor results in undesirable consequences for another.

Although noise generated by the gas turbine engine is now subject to fairly stringent governmental regulations, to date, the noise considerations were not part of the design optimization for conventional engines.

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