Gas turbine engine exhaust nozzle having a noise attenuation device driven by shape memory material actuators

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interact with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs are substantially aerodynamically unobtrusive wherein the actuation mechanism comprises a shape memory material element and wherein the tab defines a recess therein and at least a part of the element is generally disposed within the recess.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interacting with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs being substantially aerodynamically unobtrusive wherein the nozzle arrangement comprises a resilient member having a first end and a distal end, the resilient member is attached at the first end to the tab and at the distal end to the nozzle and is arranged to provide a returning force to the tab.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interacting with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs being substantially aerodynamically unobtrusive wherein the actuation mechanism comprises a shape memory material element and wherein the nozzle defines an orifice and a passage, the orifice is exposed to a gas stream and the passage extends from the orifice to the pocket and thereby provides a conduit for transmitting the thermal flux of the gas stream to the actuation mechanism.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interacting with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs being substantially aerodynamically unobtrusive and wherein the tab comprises shape memory material.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interacting with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs being substantially aerodynamically unobtrusive wherein the actuation mechanism is actuated in a response to an applied field and wherein the temperature flux is provided by the gas stream and the gas stream is any one chosen from the group comprising an ambient gas flow, a bypass flow, a core flow.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interact with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs are substantially aerodynamically unobtrusive wherein the plurality of tabs is circumferentially disposed about the nozzle wherein the shape memory material element comprises an electrostrictive material wherein, the actuation mechanism further comprises an electrical circuit, the electrical circuit comprising control apparatus, an electric generating means and electrical contact means, the electrical contact means arranged to deliver, in use, an electrical signal, generated by the electrical generating means, through the electrostrictive material, the control apparatus operable to control the electrical signal, wherein the control apparatus, operable to control the electrical signal and is operated in response to the altitude of an associated aircraft.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust oases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interact with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs are substantially aerodynamically unobtrusive wherein the plurality of tabs is circumferentially disposed about the nozzle wherein the shape memory material element comprises an electrostrictive material and wherein the electrostrictive material element comprises any one of a polymer group including polyvinylidene fluoride.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interacting with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs being substantially aerodynamically unobtrusive wherein the downstream portion of the nozzle defines a plurality of circumferentially disposed recesses, each recess receiving a tab.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interacting with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs being substantially aerodynamically unobtrusive wherein the plurality of tabs is circumferentially disposed about the nozzle wherein the actuation mechanism comprises a shape memory material element spanning between each circumferentially adjacent deployable tab, the shape memory material element having a first length and a second length, so that in use, when the shape memory material element is in its first shape the deployable tabs are in the first deployed position and when the shape memory material element is in its second shape the deployable tabs are in the second non-deployed position wherein the first length of the shape memory element is longer than the second length, so that in use and in the first deployed position the deployable tabs are angled radially outwardly.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interacting with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs being substantially aerodynamically unobtrusive wherein, in use as a noise reduction means, alternate tabs are rigidly fixed at a radially inward angle and deployable tabs are operable to move between said first deployed position at a radially outward angle, where the deployable tabs interact with a gas stream to reduce exhaust noise thereof, and said second non-deployed position, where the deployable tabs are substantially circumferentially aligned with the alternate tabs.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving the tabs between a first deployed position, in the first position the tabs interacting with a gas stream to reduce exhaust noise thereof, and a second non-deployed position, in the second position the tabs being substantially aerodynamically unobtrusive wherein, in use as a noise reduction means, alternate tabs are rigidly fixed at a second non-deployed position and deployable tabs are operable to move between said first deployed position at a radially inward angle, where the deployable tabs interact with a gas stream to reduce exhaust noise thereof, and said second non-deployed position, where the deployable tabs are substantially circumferentially aligned with the alternate tabs.

A gas turbine engine exhaust nozzle arrangement for the flow of exhaust gases therethrough between an upstream end and a downstream end thereof comprising a nozzle, a downstream portion and a plurality of tabs, each tab extending in a generally axial direction from the downstream portion of the nozzle wherein the nozzle further comprises an actuation mechanism capable of moving at least some of the tabs between a first deployed position, in the first position the tabs being angled radially outward relative to the nozzle and interact with a gas stream to reduce exhaust noise thereof and to increase the area of the nozzle, and a second position, in the second position the tabs reducing the nozzle area relative to the first position wherein the tab comprises shape memory material.