Variable area exhaust nozzle system and control method thereof

Abstract

A variable area exhaust nozzle for limiting an actual area ratio of a gas turbine engine includes a shroud assembly having a fixed shroud and an adjustable shroud, an adjustable plug, a nozzle adjustment assembly, and a controller, the controller being configured to: receive data indicating an operating speed of the gas turbine engine; determine a target area ratio based at least in part on the received data indicating the operating speed of the gas turbine engine; and operate the nozzle adjustment assembly to selectively adjust at least one of the adjustable shroud or the adjustable plug so that the actual area ratio is substantially equal to the target area ratio.

Description

Technical Field

[0001] The present subject matter relates generally to gas turbine engines and, more particularly, to a variable area exhaust nozzle system including an adjustable shroud and an adjustable plug and a method for controlling the same. Background Art

[0002] A gas turbine engine typically consists of a compressor section, a combustion section, a turbine section, and an exhaust section in a series flow sequence. In operation, air enters the inlet of the compressor section, where one or more axial or centrifugal compressors progressively compress the air until it reaches the combustion section. Fuel mixes with the compressed air and combusts within the combustion section to provide combustion gases. From the combustion section, the combustion gases flow through a hot gas path defined within the turbine section and are then exhausted from the turbine section via an exhaust nozzle.

[0003] For efficient operation of gas turbine engines, i.e., to minimize the amount of fuel required to generate a given amount of thrust, it is desirable that the flow output of the turbine and fan be precisely controlled in both volume and direction. Some gas turbine engines include exhaust nozzles with overlapping flaps and seals to vary the engine's flow output. The inventors of the present disclosure have discovered that an improved variable area exhaust nozzle would be welcome in the art. Summary of the Invention

[0004] Aspects and advantages of the disclosure will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the disclosure.

[0005] In one exemplary embodiment, a variable area exhaust nozzle for a gas turbine engine is provided. The gas turbine engine defines an axial direction. The variable area exhaust nozzle includes a shroud assembly defining an aft end and including a fixed shroud and an adjustable shroud mechanically coupled to the fixed shroud. The variable area exhaust nozzle also includes an adjustable plug slidably positioned within the fixed shroud and movable in the axial direction between a retracted position and an extended position. An annular passage is defined between the adjustable shroud and the adjustable plug. The variable area exhaust nozzle further defines an actual area ratio equal to a ratio of a nozzle outlet area to a nozzle throat area. The variable area exhaust nozzle also includes a nozzle adjustment assembly for selectively positioning at least one of the adjustable shroud or the adjustable plug.

[0006] These and other features, aspects and advantages of the present disclosure will be better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] A full and enabling disclosure of the present disclosure, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification with reference to the accompanying drawings, in which:

[0008] Figure 1 is a perspective view of an exemplary aircraft according to aspects of the present disclosure;

[0009] Figure 2 Shown above reference Figure 1 A partial cross-sectional view of a variable area exhaust nozzle of a gas engine turbine described, particularly showing the shroud assembly, adjustable plug, nozzle adjustment assembly, and controller;

[0010] Figure 3 shows a plot of target area ratio for a range of engine speeds, shown by dashed lines, and nozzle throat area, shown by solid lines, respectively, as a function of plug stroke;

[0011] Figure 4 A simplified view illustrating one embodiment of a variable area exhaust nozzle system, particularly showing an adjustable hood in a retracted position;

[0012] Figure 5 A simplified view showing another embodiment of a variable area exhaust nozzle system, particularly showing an adjustable hood in an extended position;

[0013] Figure 6 An exemplary embodiment of a support member and a hood adjustment mechanism is shown, the support member including a track system having two tracks, and the hood adjustment mechanism including at least one hood adjustment actuator;

[0014] Figure 7 a schematic cross-sectional view showing an adjustable hood in a retracted position and in an extended position;

[0015] Figure 8 a schematic cross-sectional view showing the adjustable plug in a retracted position and in an extended position; and

[0016] Figure 9 A flow chart illustrating one embodiment of a method for controlling a variable exhaust nozzle of a gas turbine engine according to aspects of the present subject matter is shown. DETAILED DESCRIPTION

[0017] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the present disclosure, rather than limitation thereof. Indeed, it will be apparent to those skilled in the art that various modifications and variations may be made to the present disclosure without departing from the scope or spirit of the present disclosure. For example, a feature shown or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the present disclosure is intended to encompass such modifications and variations as fall within the scope of the appended claims and their equivalents.

[0018] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, all embodiments described herein should be considered exemplary unless expressly stated otherwise.

[0019] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of each component.

[0020] The terms "front" and "rear" refer to relative positions within a component or system and refer to the normal operating attitude of the component or system. For example, with respect to a gas turbine engine, the front position refers to a position closer to the inlet of the gas turbine engine, while the rear position refers to a position closer to the exhaust of the gas turbine engine.

[0021] The terms "upstream" and "downstream" refer to relative directions of fluid flow in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0022] Unless otherwise indicated herein, the terms "coupled," "fixed," "attached," and the like refer to both direct coupling, fixing, or attachment as well as indirect coupling, fixing, or attachment through one or more intermediate components or features.

[0023] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0024] As used throughout the specification and claims, approximating language can be applied to modify any quantitative expression that allows variation without causing the basic function associated therewith to change. Therefore, the values ​​modified by terms such as "about," "approximately," "almost," and "substantially" are not limited to the precise values ​​specified. In some cases, approximate language can correspond to the precision of the instrument used to measure the value. For example, approximate language can refer to within a margin of 1%, 2%, 4%, 10%, 15%, or 20%. These approximate margins can be applied to a single value, to any endpoint or two endpoints of a numerical range, and / or to the margin of the range between the endpoints.

[0025] Here and throughout the specification and claims, range limitations are combined and interchanged, and unless context or language indicates otherwise, such ranges are identified and include all sub-ranges contained therein. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0026] In general, the present subject matter relates to an improved variable area exhaust nozzle system and methods for controlling the same. The described variable area exhaust nozzle operates efficiently in a variety of flight operating modes by varying the flow area based on the flight operating mode. Exhaust systems for gas turbine engines operating over a wide range of pressure ratios (i.e., nozzle throat pressure / ambient pressure, or "P8 / Pamb") require variable geometry to adjust the nozzle throat area ("A8") to meet the demands of the engine cycle. Adjusting the nozzle throat area further adjusts the area ratio (i.e., nozzle exit area / nozzle throat area, or "A9 / A8") to achieve good performance at various operating points. For example, when the engine is operating at supersonic flight speeds (i.e., Mach numbers greater than 1), the exhaust nozzle system must have a nozzle pressure ratio of 6 or 7. This nozzle pressure ratio can be achieved by reducing the flow exit area of ​​the nozzle. For subsonic flight speeds, the nozzle area must be set high to achieve optimal performance and protect the operability of the turbomachinery. The exhaust nozzle must achieve a nozzle pressure ratio of 3. Thus, by moving the adjustable plug of the exhaust nozzle described in the exemplary embodiment, a larger flow outlet area can be achieved for the same exhaust nozzle. The variable geometry aspect of the exhaust nozzle system of the present disclosure can, for example, change the nozzle pressure ratio and area ratio in response to data indicating flight mode or flight speed to meet the above requirements over a range of operating conditions, thereby achieving more efficient operation under various engine operating conditions.

[0027] Now referring to the drawings, Figure 1, an exemplary embodiment of an aircraft 100 according to aspects of the present disclosure is provided. Aircraft 100 includes an aircraft structure or airframe 105. Airframe 105 includes a fuselage 110, to which wings 120 and an empennage 130 are attached. A propulsion system 10 according to aspects of the present disclosure is attached to one or more portions of the airframe. In some cases, propulsion system 10 is attached to fuselage 110. In some other cases, propulsion system 10 is attached below, above, or through a portion of wings 120 and / or empennage 130.

[0028] In various embodiments, the propulsion system 10 is attached to the frame 105 via a pylon or other mounting structure. In yet other embodiments, the propulsion system 10 is housed within the frame, such as may be exemplified in certain supersonic military or commercial aircraft. The propulsion system 10 may generally be configured as a turbomachine, such as a gas turbine engine, comprising a compressor section, a heat addition or combustion section, and a turbine section arranged in series flow. The core engine 40 may include one or more rotor assemblies, each comprising one or more shafts coupling the respective compressor and turbine.

[0029] In the depicted embodiment, the aircraft 100 is configured as a supersonic aircraft, which is configured to operate at a flight speed greater than Mach 1. Figure 1 As shown, the propulsion system 10 defines an axial direction A. A radial plane perpendicular to the axial direction A, which is the axis of rotation of the propulsion system 10 , is defined by a radial direction R.

[0030] Certain embodiments of the propulsion system 10 are configured as a turbofan engine or a turbojet engine, including a fan assembly operatively connected to a core engine 40. It should also be understood that in other exemplary embodiments, aspects of the present disclosure may be incorporated into any other suitable type of gas turbine engine. For example, aspects of the present disclosure may be incorporated into, for example, turboshaft engines, turboprop engines, turbojet engines, industrial and marine gas turbine engines, auxiliary power units, and the like. These terms, and more specifically, gas turbine engines, may be used interchangeably to refer to the same propulsion system 10.

[0031] Now refer to Figure 2 , according to an embodiment of the present subject matter, the above reference Figure 1A partial cross-sectional view of a variable area exhaust nozzle system 200 for a gas turbine engine is depicted. As shown, the variable area exhaust nozzle system 200 is oriented in an axial direction A and includes a shroud assembly 210 and an adjustable plug 250. The shroud assembly 210 defines an aft end 205 and includes a fixed shroud 215 and an adjustable shroud 220 mechanically coupled to the fixed shroud 215. The adjustable shroud 220 is movable in the axial direction A between a retracted position and an extended position. Figure 2 The adjustable hood 220 is shown in a retracted position, wherein the adjustable hood 220 is immediately adjacent to the rear end of the fixed hood 215. Immediately adjacent can mean directly adjacent. For example, in the exemplary embodiment, the front end of the adjustable hood 220 is flush with the rear end of the fixed hood 215 in the retracted position. In the extended position, the adjustable hood 220 is spaced apart from the fixed hood 215, thereby defining a bypass passage 225. Spaced apart refers to any position in which the adjustable hood 220 is not in the retracted position and is immediately adjacent to the fixed hood 215.

[0032] Figure 2 Also shown is an adjustable plug 250 slidably positioned within the stationary shroud 215. The adjustable plug 250 is shown to include a contoured tail cone 256 and a shaft 255, wherein the contoured tail cone 256 is defined at the rear end 205 of the shaft 255. However, it should be understood that the adjustable plug 250 can have any shape operable with the described variable area exhaust nozzle system 200. Furthermore, the adjustable plug 250 is movable along an axial direction A between a retracted position and an extended position. The retracted position of the adjustable plug 250 is shown in solid lines, wherein substantially the entirety of the adjustable plug 250 is within the stationary shroud 215. The extended position of the adjustable plug 250 is shown in dashed lines, wherein substantially the entirety of the contoured tail cone 256 is positioned outside of the stationary shroud 215. As shown, the adjustable plug 250 further defines an annular passage 240 between the adjustable shroud 220 and the adjustable plug 250.

[0033] The variable area exhaust nozzle system 200 defines an actual area ratio 20. As used herein, the term "area ratio" is equal to the ratio of the nozzle outlet area 21 to the nozzle throat area 22. In this regard, the "nozzle outlet area" generally refers to the maximum cross-sectional area of ​​the annular passage 240 at the aft end 205 of the shroud assembly 210 (generally designated herein as "A9"). Furthermore, as described above, the adjustable shroud 220 can be extended to define a bypass passage 225, in which case the cross-sectional area of ​​the bypass passage 225 is further included in the nozzle outlet area 21. Furthermore, the "nozzle throat area" generally refers to the minimum cross-sectional area of ​​the annular passage 240 at the widest point of the profiled tail cone 256 (generally designated herein as "A8"). According to the exemplary embodiment shown, the cross-sectional nozzle throat area 22 (A8) and the nozzle outlet area 21 (A9) can be measured within a radial plane defined by the radial direction R. The nozzle throat area 22 (A8) is the minimum cross-sectional area of ​​the annular passage 240 between the widest portion of the profiled tail cone 256 and the shroud assembly 210. The maximum cross-sectional area of ​​the annular passage 240 at the aft end 205 of the shroud assembly 210, or the nozzle exit area 21 (A9), is the area of ​​the flow exiting the nozzle. It should be understood that this area ratio may refer to any range of area ratios in which the propulsion system 10 (e.g., a gas turbine engine) may operate, and that the terms A8 and A9 may also include definitions known to those of ordinary skill in the art.

[0034] These area ratios are important for efficient operation of the gas turbine engine, i.e., minimizing the amount of fuel required to generate a given amount of thrust. Therefore, it is desirable that the flow output of the turbine and fan be precisely controlled in both volume and direction. Flow control can be achieved by adjusting the geometry of the variable area exhaust nozzle system 200, and subsequently adjusting the nozzle exit area 21 and / or the nozzle throat area 22 to change the actual area ratio 20 to match the target area ratio 25, in order to achieve optimized flight.

[0035] As used herein, the term "actual area ratio" is the measured area ratio of the variable area exhaust nozzle system 200. The term "target area ratio" is the desired area ratio of the variable area exhaust nozzle system 200 based on the operating speed. The controller 270 implements an algorithm to drive the actual area ratio 20 to the target area ratio 25.

[0036] Nozzle adjustment assembly 260, operably coupled to controller 270, selectively positions adjustable shroud 220, adjustable plug 250, or both. Controller 270 is configured to obtain an operating speed of the gas turbine engine, determine a target area ratio 25 based at least in part on the operating speed of the gas turbine engine, and operate nozzle adjustment assembly 260 to selectively adjust at least one of adjustable shroud 220 or adjustable plug 250 so that the actual area ratio 20 is substantially equal to the target area ratio 25. In the exemplary embodiment, nozzle adjustment assembly 260 includes a shroud adjustment mechanism 265 that mechanically couples adjustable shroud 220 to fixed shroud 215 to selectively move adjustable shroud 220 relative to fixed shroud 215 in an axial direction A toward aft end 205. Nozzle adjustment assembly 260 may also include a plug adjustment mechanism 268. Plug adjustment mechanism 268 mechanically couples adjustable plug 250 to the gas turbine engine and selectively moves adjustable plug 250 relative to fixed shroud 215 in an axial direction A toward aft end 205. By selectively positioning the adjustable shroud 220 or the adjustable plug 250 , the nozzle adjustment assembly 260 is able to change the nozzle throat area 22 ( A8 ) or the nozzle outlet area 21 ( A9 ), thereby changing the actual area ratio 20 to meet the target area ratio 25 .

[0037] For example, a brief reference Figure 3 , provides a plot of a target area ratio 25 (A9 / A8) for a range of engine speeds, shown by the dashed line. Typically, the area ratio of a gas turbine engine can range between about 1 and about 1.3. Figure 3 Also shown on the solid line is the nozzle throat area 22 (A8), which is shown as the nozzle throat area 22 (A8) for a given stroke divided by the minimum nozzle throat area ("A8"). min ”) as a function of the stroke percentage of the adjustable plug 250. The stroke percentage of the adjustable plug 250 is calculated as a ratio of the plug stroke length 50, where the plug stroke length 50 is the maximum distance between the tip of the contoured tail cone 256 of the adjustable plug 250 in the retracted position and the tip of the contoured tail cone 256 of the adjustable plug 250 in the extended position.

[0038] Furthermore, as will be appreciated, the operating speed of the gas turbine engine is related to the flight operating mode (e.g., supercruise, subsonic cruise, transonic cruise, or takeoff). Figure 3As shown, the stroke percentage of the adjustable plug 250 is related to the flight operating mode of the gas turbine engine. For example, when the gas turbine engine is in the supersonic cruise operating mode, the adjustable plug 250 is in an approximately -100% stroke position (e.g., fully retracted position). Similarly, when the adjustable plug 250 is in an approximately 100% stroke position (e.g., fully extended position), the gas turbine engine may be in the sideline flight operating mode. When the gas turbine engine is in the transonic cruise operating mode, the adjustable plug 250 is in an approximately 0% stroke position. The 0% stroke position may be an intermediate position between the fully retracted position and the fully extended position. The 0% stroke position may be a position halfway between the fully retracted position and the fully extended position, or may be closer to the fully retracted position or closer to the fully extended position.

[0039] like Figure 3 As shown, when the flight operating mode is supersonic cruise (e.g., when the adjustable plug 250 is in the fully retracted position), the target area ratio 25 (A9 / A8) can be in the range of 1.239 to about 1.280, about 1.245 to about 1.275, or about 1.250 to about 1.260. Similarly, the nozzle throat area 22 (A8) can be in the range of A8. min About 105% to about 113% of A8 min of about 107% to about 111%, or A8 min The range of about 108% to about 109% is as follows.

[0040] Still refer to Figure 3 When the flight operating mode is transonic cruise (e.g., when the adjustable plug 250 is in the neutral position), the target area ratio 25 (A9 / A8) may be in the range of about 1.280 to about 1, about 1.270 to about 1.060, about 1.260 to about 1.060, about 1.255 to about 1.100, about 1.250 to about 1.160, or about 1.250 to about 1.240. Similarly, the nozzle throat area 22 (A8) may be in the range of A8. min About 97% to about 105%, A8 min About 99% to about 103% of A8 min In addition, when the flight operating mode is takeoff (e.g., when the adjustable plug 250 is in the extended position), the nozzle throat area 22 (A8) can be in the range of about 100% to about 101% of A8. min About 107% to about 119% of A8 min About 109% to about 117% of A8 min About 111% to about 115% of A8 minTarget area ratio 25 may be in the range of about 112% to about 114% of target area ratio 25. When the flight operating mode is sideline (e.g., when adjustable plug 250 is in the fully extended position), nozzle throat area 22 (A8) may be in the range of about 119% to about 125%, about 121% to about 124%, or about 122% to about 123%. Furthermore, it should be understood that target area ratio 25 may vary depending on engine type, application, geometry, and various other factors. The values ​​of target area ratio 25 provided herein are exemplary only and are not intended to limit the scope of the present subject matter in any way.

[0041] Return Reference Figure 2 , the controller 270 is shown as being wirelessly coupled to the nozzle adjustment assembly 260. For example, according to certain embodiments, the controller 270 may include a memory and a microprocessor, such as a general-purpose or special-purpose microprocessor operable to execute programmed instructions or microcontrol code associated with the cleaning cycle. The memory may represent a random access memory (such as DRAM) or a read-only memory (such as ROM or FLASH). In one embodiment, the processor executes the programmed instructions stored in the memory. The memory may be a separate component from the processor, or may be included on board within the processor. Alternatively, the controller 270 may be constructed without the use of a microprocessor, for example, using a combination of discrete analog and / or digital logic circuits (such as switches, amplifiers, integrators, comparators, flip-flops, and gates, etc.) to perform control functions, rather than relying on software. In another embodiment, the controller 270 may be directly mechanically coupled to the nozzle adjustment assembly 260.

[0042] Now refer to Figure 4 and Figure 5, a simplified view of one embodiment of a variable area exhaust nozzle system 200 for a gas turbine engine is shown, according to aspects of the present subject matter. System 200 may include one or more support structures positioned proximate the aft end 205 of a fixed shroud 215, where "proximate the aft end" refers to a location closer to the aft end than the forward end along the gas turbine engine. In the exemplary embodiment, the one or more support structures are a first support member 218A and a second support member 218B, or collectively, support members 218, which extend from the fixed shroud 215 in an axial direction A and are mechanically coupled to the adjustable shroud. In one embodiment, support members 218 are fabricated as part of the fixed shroud 215. Alternatively, support members 218 may be fabricated separately and attached to the aft end 205 of the fixed shroud 215 via welding, screws, or any other means. As shown in the illustrative embodiment, each of support members 218A, 218B may define an elongated portion extending from the fixed shroud 215. In the exemplary embodiment, two support members 218 extend on opposite sides of the adjustable shroud 220. Furthermore, the support member 218 may define a receiving structure that mechanically couples the adjustable hood 220 to the support member 218 .

[0043] Brief Reference Figure 6 , illustrates an exemplary embodiment of a support member 218 extending in an axial direction A from the fixed shroud 215 to the adjustable shroud 220. In the illustrated embodiment, the receiving structure is mechanically coupled to one or more track systems 267. Typically, the shroud adjustment mechanism 265 may include at least one shroud adjustment actuator 266 mechanically coupled to each track system 267 within each support member 218A, 218B, or both support members 218. Each track system 267 may include one or more tracks, such as, for example, a first track 267A and a second track 267B as shown. For example, the track system may be mechanically coupled in an axial direction A to an elongated portion of the support member 218 of the fixed shroud 215, wherein the first track 267A extends along a first elongated portion of the fixed shroud 215 and the second track 267B extends along a second elongated portion of the fixed shroud 215. In the illustrated diagram, each track 267A, 267B is attached to an actuator 266A, 266B, respectively. Furthermore, in some embodiments, actuators 266A and 266B may be hydraulic actuators or electric actuators.

[0044] It should be understood that, in the alternative, the hood adjustment mechanism 265 may include a hinge or pivot mechanism that allows the adjustable hood 220 to rotate or pivot away from the fixed shroud 215. In this particular embodiment, the hood adjustment mechanism 265 does not move the adjustable hood 220 in the axial direction A, but rather moves the adjustable hood 220 in the radial direction R.

[0045] Return Reference Figure 4, the adjustable hood 220 is shown in a retracted position proximate to the rear end 205 of the fixed hood 215. For example, the adjustable hood 220 can be directly adjacent to or flush with the rear end 205 of the fixed hood 215. As shown in the illustrative embodiment, the one or more support members 218 include two or more elongated portions that extend through the adjustable hood 220 to the rear end 205 of the adjustable hood 220 when the hood 220 is in its retracted position. It should be understood that the two or more elongated portions may alternatively extend only partially through the adjustable hood 220, for example, the elongated portions may extend through less than half, approximately half, or more than half of the adjustable hood 220.

[0046] Now refer to Figure 5 , the adjustable shroud 220 is shown in the extended position. As previously discussed, the space between the adjustable shroud 220 and the fixed shroud 215 is a bypass passage 225. By opening the bypass passage 225, the flow output from the gas turbine engine can exit through the bypass passage 225, and the nozzle outlet area 21 (A9) is increased. Due to the direct relationship between the nozzle outlet area 21 (A9) and the actual area ratio 20, the actual area ratio 20 is also increased.

[0047] Now refer to Figure 7 , shows a schematic cross-sectional view of a variable area exhaust nozzle system 200. The diagram illustrates the adjustable shroud 220 in a retracted position (shown in dashed lines) and an extended position (shown in solid lines). In the illustrative embodiment, the adjustable plug 250 is shown in the retracted position. As described above, the extended position of the adjustable shroud 220 defines a bypass passage 225 through which the flow output can exit, thereby increasing the nozzle outlet area 21 (A9) and the effective area ratio 20.

[0048] It should be understood that while the adjustable hood 220 can be moved to either the retracted position or the extended position, the adjustable hood 220 can also be moved to any position between the retracted and extended positions along the axial direction A. For example, the adjustable hood 220 in the retracted position can be positioned less than halfway, halfway, or more than halfway of the extended position. Alternatively, the adjustable hood 220 in the extended position can be positioned less than halfway, halfway, or more than halfway of the retracted position.

[0049] Furthermore, in the illustrative embodiment, the hood stroke length 60 is shown as the maximum distance between the tip of the rear end 205 of the adjustable hood 220 in the retracted and extended positions. The hood stroke length 60 can vary in length, for example, between about 20 and about 30 centimeters, such as between about 22 and about 28 centimeters, such as between about 24 and about 27 centimeters, such as between about 25 and about 26 centimeters.

[0050] Now refer to Figure 8 , shows another cross-sectional schematic diagram of the variable area exhaust nozzle system 200. This diagram shows the adjustable shroud 220 in a retracted position, and the adjustable plug 250 in a retracted position indicated by solid lines and an extended position indicated by dashed lines. As shown in the exemplary embodiment, the adjustable plug 250 is slidably positioned within the fixed shroud 215 and is movable along the axial direction A between a retracted position and an extended position. Moving the adjustable plug 250 between the retracted and extended positions changes the nozzle throat area 22 (e.g., A8). For example, by moving the adjustable plug 250 to the extended position, the nozzle throat area 22 (e.g., A8) increases and the effective area ratio 20 decreases. Alternatively, moving the adjustable plug 250 to the retracted position decreases the nozzle throat area 22 (A8) and increases the effective area ratio 20.

[0051] Still refer to Figure 8 , the diagram illustrates a nozzle adjustment assembly 260 including a plug adjustment mechanism 268. As previously described, the plug adjustment mechanism 268 slidably couples the adjustable plug 250 to the propulsion system 10 for selectively moving the adjustable plug 250 in the axial direction A relative to the fixed shroud 215. For example, the plug adjustment mechanism 268 may include a lever arm attached to the shaft 255 of the adjustable plug 250 and at least one plug adjustment actuator 266 mechanically coupled to the lever arm for moving the adjustable plug 250 between a retracted position and an extended position. In particular embodiments, the plug adjustment actuator 266 may be a hydraulic actuator or an electric actuator.

[0052] It should be understood that while the adjustable plug 250 can be moved to either the retracted position or the extended position, the adjustable plug 250 can also be moved to any position between the retracted position and the extended position along the axial direction A. For example, the adjustable plug 250 in the retracted position can be positioned less than halfway, halfway, or more than halfway of the extended position. Alternatively, the adjustable plug 250 in the extended position can be positioned less than halfway, halfway, or more than halfway of the retracted position.

[0053] In addition, still refer to Figure 8 , the plug stroke length 50 is shown as the maximum distance between the tips of the profiled tail cone 256 of the adjustable plug 250 in the retracted and extended positions. The plug stroke length 50 of the adjustable plug 250 can be between about 60 and about 90 centimeters, such as between about 65 and about 85 centimeters, such as between about 70 and about 80 centimeters, such as between about 75 and about 77 centimeters.

[0054] Now refer to Figure 9, a flow chart illustrating an exemplary method 300 for controlling a variable area exhaust nozzle system 200 according to aspects of the present subject matter is shown. Specifically, the controller 270 of the variable area exhaust nozzle system 200 can be configured to perform the method 300. The method 300 includes receiving data indicative of an operating speed of a gas turbine engine at block 310, determining a target area ratio 25 based at least in part on the received data indicative of the operating speed of the gas turbine engine at block 320, and operating the nozzle adjustment assembly 260 to selectively adjust at least one of the adjustable shroud 220 or the adjustable plug 250 at block 330 so that the actual area ratio 20 is substantially equivalent to the target area ratio 25.

[0055] Frame 310 includes receiving data indicating the operating speed of the gas turbine engine. The operating speed is the speed that the operator of the aircraft 100 wants to achieve and is related to the flight operating mode (e.g., supersonic cruise, transonic cruise, or takeoff). It should be understood that the operating speed may also include any other speed that the gas turbine engine is capable of achieving. In addition, the operating speed may be input into the controller 270 directly by the operator of the aircraft, through a remote electronic communication device, through a control panel, or by any other means known to those of ordinary skill in the art. Alternatively, after the aircraft operator enters the flight operating mode, the operating speed may be measured, calculated, or otherwise determined by the controller 270 or other automated system. As known to those of ordinary skill in the art, the automated system or controller 270 may also obtain the operating speed or flight operating mode directly from an internal system of the gas turbine engine.

[0056] At 320, a target area ratio is determined based at least in part on the received data indicative of the operating speed of the gas turbine engine. The controller 270, computer, or other automated system may be used to calculate the target area ratio 25. For example, with brief reference to Figure 3 If the operating speed of the gas turbine engine is the speed of the takeoff flight operating mode and the gas turbine engine needs to enter the transonic cruise mode, the controller 270 will determine the target area ratio 25 corresponding to the transonic cruise flight operating mode based on the current operating speed.

[0057] After determining the target area ratio 25, controller 270 operates nozzle adjustment assembly 260 at 330 to selectively adjust at least one of adjustable hood 220 or adjustable plug 250 so that the actual area ratio 20 is substantially equal to the target area ratio 25. For example, controller 270 determines the current position of variable area exhaust nozzle system 200, i.e., the actual area ratio 20, and compares the actual area ratio 20 to the target area ratio 25. Controller 270 may then send a signal to nozzle adjustment assembly 260 to position the adjustable hood 220, the adjustable plug 250, or both. In some embodiments, controller 270 may be programmed with the geometry of the adjustable hood 220 and the adjustable plug 250 for a specific flight operating mode and / or speed. Controller 270 may use this geometry database to determine the position of the adjustable hood 220 and the adjustable plug 250 to achieve the target area ratio 25. According to alternative embodiments, controller 270 may also include position sensors on the adjustable hood 220 and the adjustable plug 250. The controller 270 will use the sensor feedback to position the adjustable hood 220 and the adjustable plug 250 accordingly.

[0058] For example, if the actual area ratio 20 is less than the target area ratio 25, the controller 270 will send a signal to the nozzle adjustment assembly 260 to move the adjustable hood 220 in the axial direction A toward its extended position, thereby increasing the nozzle outlet area 21 (A9). The adjustable hood 220 will move until the actual area ratio 20 is substantially equal to the target area ratio 25. In this embodiment, the nozzle adjustment assembly 260 can use a hood adjustment mechanism 265 to move the adjustable hood 220. Operating the hood adjustment mechanism 265 can include positioning the adjustable hood 220 in a retracted position, an extended position, or a position between the retracted position and the extended position. In some embodiments, the adjustable plug 250 can remain in its retracted position when the adjustable hood 220 is moved into position. It should be understood that the controller 270 can be programmed or can access a database of positions of adjustable plugs or hoods associated with target area ratios.

[0059] In another example, if the actual area ratio 20 is greater than the target area ratio 25, the adjustable plug 250 will move in the axial direction A toward its extended position. Moving the adjustable plug 250 will increase the nozzle throat area 22 (A8). The nozzle adjustment assembly 260 can use the plug adjustment mechanism 268 to move the adjustable plug 250 until the actual area ratio 20 is substantially equal to the target area ratio 25. In this embodiment, the nozzle adjustment assembly 260 can use the plug adjustment mechanism 268 to move the adjustable plug 250. The plug adjustment mechanism 268 can position the adjustable plug 250 in the retracted position, the extended position, or a position between the retracted and extended positions. In some embodiments, the adjustable hood 220 can remain in its retracted position while the adjustable plug 250 is moved into position.

[0060] Furthermore, in an exemplary embodiment, Figure 9 The actual area ratio 20 or target area ratio 25 shown may vary within a range of about 1 to about 1.3, about 1 to about 1.290, or about 1 to about 1.280.

[0061] It should be understood that the variable area exhaust nozzle can be used in any compatible engine. In addition, the variable exhaust nozzle system can include other embodiments that improve the operating efficiency of the gas turbine engine. Those skilled in the art will recognize that the inherent flexibility of the adjustable shroud and adjustable plug combination allows for a variety of possible configurations, combinations, and divisions of tasks and functions between and among the components.

[0062] Further aspects of the invention are provided by the subject matter of the following clauses:

[0063] 1. A variable area exhaust nozzle for a gas turbine engine, the gas turbine engine defining an axial direction, the variable area exhaust nozzle comprising: a shroud assembly, the shroud assembly including a fixed shroud and an adjustable shroud mechanically coupled to the fixed shroud, the shroud assembly defining a rear end; an adjustable plug slidably positioned within the fixed shroud and capable of moving along the axial direction between a retracted position and an extended position, wherein an annular channel is defined between the adjustable shroud and the adjustable plug, and wherein the variable area exhaust nozzle defines an actual area ratio equal to a ratio of a nozzle outlet area to a nozzle throat area; and a nozzle adjustment assembly for selectively positioning at least one of the adjustable shroud or the adjustable plug.

[0064] 2. A variable area exhaust nozzle according to any of the preceding clauses, further comprising: a controller operably connected to the nozzle adjustment assembly, the controller being configured to: receive data indicating an operating speed of the gas turbine engine; determine a target area ratio based at least in part on the received data indicating the operating speed of the gas turbine engine; and operate the nozzle adjustment assembly to selectively adjust at least one of the adjustable hood or the adjustable plug so that the actual area ratio is substantially equal to the target area ratio.

[0065] 3. The variable area exhaust nozzle of any preceding clause, wherein the target area ratio is between about 1 and about 1.3.

[0066] 4. A variable area exhaust nozzle according to any preceding clause, wherein said adjustable shroud is movable in said axial direction between a retracted position and an extended position.

[0067] 5. A variable area exhaust nozzle according to any preceding clause, wherein the adjustable shroud is proximate the rear end of the fixed shroud in the retracted position and is spaced apart from the rear end of the fixed shroud in the extended position to define a bypass passage.

[0068] 6. A variable area exhaust nozzle according to any preceding clause, wherein said adjustable plug is movable in said axial direction between a retracted position and an extended position.

[0069] 7. A variable area exhaust nozzle according to any preceding clause, wherein the adjustable hood defines a hood stroke length of between about 20 centimeters and about 30 centimeters.

[0070] 8. The variable area exhaust nozzle of any preceding clause, wherein the adjustable plug comprises a shaft slidably coupled to the gas turbine engine and defining an aft end; and a contoured tail cone defined at the aft end of the shaft.

[0071] 9. A variable area exhaust nozzle according to any preceding clause, wherein the adjustable plug defines a plug stroke length of between about 60 centimeters and about 90 centimeters.

[0072] 10. A variable area exhaust nozzle according to any preceding clause, wherein the nozzle adjustment assembly includes: a hood adjustment mechanism, which mechanically connects the adjustable hood to the fixed shroud for selectively moving the adjustable hood relative to the fixed shroud; and a plug adjustment mechanism, which slidably connects the adjustable plug to the gas turbine engine for selectively moving the adjustable plug relative to the fixed shroud.

[0073] 11. The variable area exhaust nozzle of any preceding clause, wherein the shroud assembly comprises: one or more support structures, wherein the one or more support structures are positioned proximate the aft end of the shroud assembly.

[0074] 12. The variable area exhaust nozzle of any preceding clause, wherein the one or more support structures further comprise: a first support member; and a second support member, wherein each of the first support member and the second support member is mechanically coupled to the adjustable hood.

[0075] 13. A variable area exhaust nozzle according to any preceding clause, wherein the cover adjustment mechanism further includes: a first track, the first track extending along the axial direction of the first support member; a second track, the second track extending along the axial direction of the second support member; and at least one cover adjustment actuator, the at least one cover adjustment actuator being mechanically connected to the first track, the second track, or both.

[0076] 14. A variable area exhaust nozzle according to any preceding clause, wherein the plug adjustment mechanism further comprises: a lever arm attached to the shaft of the adjustable plug; and at least one plug adjustment actuator mechanically coupled to the lever arm.

[0077] 15. A variable area exhaust nozzle according to any preceding clause, wherein said at least one plug adjustment actuator is a hydraulic actuator or an electric actuator.

[0078] 16. A method of operating a variable exhaust nozzle for a gas turbine engine, the gas turbine engine defining an axial direction, the variable exhaust nozzle comprising: a shroud assembly, the shroud assembly comprising a fixed shroud and an adjustable shroud, the adjustable shroud being mechanically coupled to the fixed shroud and movable along the axial direction; an adjustable plug slidably positioned within the fixed shroud and movable along the axial direction; and a nozzle adjustment assembly for selectively positioning at least one of the adjustable shroud or the adjustable plug, wherein the variable exhaust nozzle defines an actual area ratio equal to a ratio of a nozzle outlet area to a nozzle throat area, the method comprising: receiving data indicative of an operating speed of the gas turbine engine; determining a target area ratio based at least in part on the received data indicative of the operating speed of the gas turbine engine; and operating the nozzle adjustment assembly to selectively adjust at least one of the adjustable shroud or the adjustable plug so that the actual area ratio is substantially equal to the target area ratio.

[0079] 17. A method according to any preceding clause, wherein the target area ratio is between about 1 and 1.3.

[0080] 18. The method of any preceding clause, wherein operating the nozzle adjustment assembly further comprises operating at least one of a shroud adjustment mechanism or a plug adjustment mechanism.

[0081] 19. The method of any preceding clause, wherein operating at least one of the hood adjustment mechanism or the plug adjustment mechanism comprises positioning the adjustable hood in a retracted position, an extended position, or a position between the retracted and extended positions.

[0082] 20. The method of any preceding clause, wherein operating at least one of the hood adjustment mechanism or the plug adjustment mechanism comprises positioning the adjustable plug in a retracted position, an extended position, or a position between the retracted and extended positions.

[0083] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any device or system and performing any combined methods. The patentable scope of the disclosure is defined by the claims and may include other examples that occur to those skilled in the art. If these other examples include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims, then these other examples are intended to fall within the scope of the claims.

Claims

1. A variable area exhaust nozzle for a gas turbine engine, the gas turbine engine defining an axial direction, characterized in that The variable area exhaust nozzle comprises: a shroud assembly including a fixed shroud and an adjustable shroud mechanically coupled to the fixed shroud, the shroud assembly defining a rearward end; an adjustable plug slidably positioned within the fixed shroud and movable in the axial direction between a retracted position and an extended position, wherein an annular passage is defined between the adjustable shroud and the adjustable plug, and wherein the variable area exhaust nozzle defines an actual area ratio equal to a ratio of a nozzle outlet area to a nozzle throat area; a nozzle adjustment assembly for selectively positioning at least one of the adjustable hood or the adjustable plug; and a controller operably coupled to the nozzle adjustment assembly, the controller being configured to: receiving data indicative of an operating speed of the gas turbine engine; determining a target area ratio based at least in part on received data indicative of the operating speed of the gas turbine engine; and The nozzle adjustment assembly is operated to selectively adjust at least one of the adjustable hood or the adjustable plug so that the actual area ratio is substantially equal to the target area ratio.

2. The variable area exhaust nozzle according to claim 1, characterized in that: in, The target area ratio is between about 1 and about 1.

3.

3. The variable area exhaust nozzle according to claim 1, characterized in that in, The adjustable hood is movable in the axial direction between a retracted position and an extended position.

4. The variable area exhaust nozzle according to claim 3, characterized in that: in, The adjustable hood is proximate to the rear end of the fixed shroud in the retracted position and is spaced apart from the rear end of the fixed shroud in the extended position to define a bypass passage.

5. The variable area exhaust nozzle according to claim 1, characterized in that: in, The adjustable plug is movable in the axial direction between a retracted position and an extended position.

6. The variable area exhaust nozzle according to claim 1, characterized in that in, The adjustable hood defines a hood stroke length of between approximately 20 centimeters and approximately 30 centimeters.

7. The variable area exhaust nozzle according to claim 1, characterized in that: in, The adjustable plug comprises: a shaft slidably coupled to the gas turbine engine and defining an aft end; and A profiled tail cone is defined at the rear end of the shaft.

8. The variable area exhaust nozzle according to claim 1, characterized in that in, The adjustable plug defines a plug stroke length of between about 60 centimeters and about 90 centimeters.

9. The variable area exhaust nozzle according to claim 7, characterized in that: in, The nozzle adjustment assembly includes: a hood adjustment mechanism mechanically coupling the adjustable hood to the fixed hood for selectively moving the adjustable hood relative to the fixed hood; and A plug adjustment mechanism slidably couples the adjustable plug to the gas turbine engine for selectively moving the adjustable plug relative to the fixed shroud.

10. The variable area exhaust nozzle according to claim 9, characterized in that in, The shield assembly comprises: One or more support structures, wherein the one or more support structures are positioned proximate the rear end of the shroud assembly.

11. The variable area exhaust nozzle according to claim 10, characterized in that: in, The one or more support structures further include: a first support member; and A second support member, wherein each of the first support member and the second support member is mechanically coupled to the adjustable hood.

12. The variable area exhaust nozzle according to claim 11, characterized in that in, The hood adjustment mechanism further comprises: a first rail extending along the axial direction of the first support member; a second rail extending in the axial direction of the second support member; and At least one hood adjustment actuator is mechanically coupled to the first rail, the second rail, or both.

13. The variable area exhaust nozzle according to claim 9, characterized in that in, The plug adjustment mechanism further comprises: a lever arm attached to the shaft of the adjustable plug; and At least one plug adjustment actuator is mechanically coupled to the lever arm.

14. The variable area exhaust nozzle according to claim 13, characterized in that in, The at least one plug adjustment actuator is a hydraulic actuator or an electric actuator.

15. A method of operating a variable exhaust nozzle for a gas turbine engine, the gas turbine engine defining an axial direction, characterized in that: The variable exhaust nozzle comprises: a shroud assembly including a fixed shroud and an adjustable shroud, the adjustable shroud being mechanically coupled to the fixed shroud and movable in the axial direction; an adjustable plug slidably positioned within the fixed shroud and movable in the axial direction; and a nozzle adjustment assembly for selectively positioning at least one of the adjustable shroud or the adjustable plug, wherein the variable exhaust nozzle defines an actual area ratio, the actual area ratio being equal to a ratio of a nozzle outlet area to a nozzle throat area, the method comprising: receiving data indicative of an operating speed of the gas turbine engine; determining a target area ratio based at least in part on received data indicative of the operating speed of the gas turbine engine; and The nozzle adjustment assembly is operated to selectively adjust at least one of the adjustable hood or the adjustable plug so that the actual area ratio is substantially equal to the target area ratio.

16. The method according to claim 15, characterized in that in, The target area ratio is between about 1 and 1.

3.

17. The method according to claim 15, characterized in that in, Operating the nozzle adjustment assembly further includes: At least one of the hood adjustment mechanism or the plug adjustment mechanism is operated.

18. The method according to claim 17, characterized in that in, Operating at least one of the hood adjustment mechanism or the plug adjustment mechanism includes: The adjustable hood is positioned in a retracted position, an extended position, or a position between the retracted and extended positions.

19. The method according to claim 17, wherein in, Operating at least one of the hood adjustment mechanism or the plug adjustment mechanism includes: The adjustable plug is positioned in a retracted position, an extended position, or a position between the retracted and extended positions.

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