Gas turbine engine

Abstract

A gas turbine engine according to one aspect of the present disclosure comprises: a tail cone; an exhaust nozzle that covers the tail cone from the outside in the radial direction such that an exhaust gas flow path is formed between the tail cone and the exhaust nozzle; a cylindrical support casing that is positioned upstream of the exhaust nozzle, and supports the exhaust nozzle so as to be movable in the front-rear direction; and an actuator that is attached to the exhaust nozzle or the support casing, and changes the cross-sectional area of the exhaust gas flow path by moving the exhaust nozzle in the front-rear direction relative to the tail cone.

Description

gas turbine engine

[0001] The present disclosure relates to gas turbine engines.

[0002] Patent Document 1 listed below discloses a gas turbine engine equipped with a variable exhaust nozzle that can adjust the exhaust area.

[0003] Japanese Patent Application Publication No. 10-176604

[0004] The gas turbine engine described in Patent Document 1 has a complex structure because the exhaust area is adjusted by deforming the variable exhaust nozzle. Therefore, one aspect of the present disclosure aims to provide a gas turbine engine that has an exhaust nozzle with a simple structure but is capable of changing the cross-sectional area of ​​the exhaust gas flow path.

[0005] A gas turbine engine according to one aspect of the present disclosure comprises a tail cone, an exhaust nozzle that covers the tail cone from the radially outer side and forms an exhaust gas flow path between the tail cone and the tail cone, a cylindrical support casing that is located upstream of the exhaust nozzle and supports the exhaust nozzle so that it can move in a forward and backward direction, and an actuator that is attached to the exhaust nozzle or the support casing and changes the cross-sectional area of ​​the exhaust gas flow path by moving the exhaust nozzle in a forward and backward direction relative to the tail cone.

[0006] According to one aspect of the present disclosure, the cross-sectional area of ​​the exhaust gas flow path can be changed even with an exhaust nozzle having a simple structure.

[0007] Fig. 1 is a schematic diagram of a gas turbine engine. Fig. 2 is an enlarged view of the exhaust gas flow path and its vicinity, showing the exhaust nozzle in its normal position. Fig. 3 is an enlarged view of the exhaust gas flow path and its vicinity, showing the exhaust nozzle in its normal position and in its movable position.

[0008] (Outline of Gas Turbine Engine) An embodiment will now be described. First, an outline of a gas turbine engine (hereinafter simply referred to as "engine") 100 according to an embodiment will be described. FIG. 1 is a schematic diagram of the engine 100 according to this embodiment. The left side of the page in FIG. 1 is the front of the engine 100, and the right side of the page in FIG. 1 is the rear of the engine 100. Hereinafter, the front of the engine 100 will be simply referred to as the "front direction," the rear of the engine 100 will be simply referred to as the "rear direction," the axial direction of the engine 100 will be simply referred to as the "axial direction," the direction around the axis of the engine 100 will be simply referred to as the "circumferential direction," and the radial direction of the engine 100 will be simply referred to as the "radial direction."

[0009] The engine 100 of this embodiment is a two-screw turbofan engine for aircraft. However, the application and type of the engine 100 are not limited. The engine 100 supplies air taken in by a fan 10 to a low-pressure compressor 11 and also supplies the air to a bypass flow path 13 located radially outward of the low-pressure compressor 11. The air supplied to the low-pressure compressor 11 is compressed by the low-pressure compressor 11 and further compressed by the high-pressure compressor 12, and then supplied to a combustor 14. In the combustor 14, fuel is sprayed into the compressed air and combusted to generate high-temperature and high-pressure combustion gas.

[0010] The combustion gas generated in the combustor 14 is supplied to the high-pressure turbine 15 and the low-pressure turbine 16, and rotates the high-pressure turbine 15 and the low-pressure turbine 16. The high-pressure turbine 15 is connected to the high-pressure compressor 12 via an external shaft 17. Therefore, the high-pressure compressor 12 rotates as the high-pressure turbine 15 is rotated. Furthermore, the low-pressure turbine 16 is connected to the low-pressure compressor 11 and the fan 10 via an internal shaft 18. Therefore, the low-pressure compressor 11 and the fan 10 rotate as the low-pressure turbine 16 is rotated.

[0011] The combustion gas that has passed through the high-pressure turbine 15 and the low-pressure turbine 16 joins with the air that has passed through the bypass passage 13, and passes through the exhaust gas passage 19 and is discharged rearward as exhaust gas. The engine 100 according to this embodiment is capable of changing the cross-sectional area of ​​this exhaust gas passage 19. The purpose of changing the cross-sectional area of ​​the exhaust gas passage 19 is not limited, and may be, for example, to adjust the thrust of the engine 100.

[0012] (Mechanism for changing the cross-sectional area of ​​the exhaust gas flow passage) Next, a mechanism for changing the cross-sectional area of ​​the exhaust gas flow passage 19 will be described. Fig. 2 is an enlarged view of the vicinity of the exhaust gas flow passage 19 shown in Fig. 1. The engine 100 according to this embodiment includes a tail cone 21, an exhaust nozzle 22, a support casing 23, and a variable nozzle mechanism 24. These components will be described in order below.

[0013] 1 , the tail cone 21 is located downstream of the high-pressure turbine 15 and the low-pressure turbine 16 in the direction of combustion gas flow, and is a component that guides the exhaust gas that has passed through the high-pressure turbine 15 and the low-pressure turbine 16 rearward. The tail cone 21 has a conical shape with an outer diameter that is smaller at the rear portion than at the front portion. However, the tail cone 21 does not have to be strictly conical, and the tip may be hemispherical, for example, and the shape of the tail cone 21 is not particularly limited.

[0014] <Exhaust Nozzle> The exhaust nozzle 22 is a component that covers a portion of the tail cone 21 from the radially outer side. The exhaust nozzle 22 forms an exhaust gas flow path 19 between the exhaust nozzle 22 and the tail cone 21. Although the exhaust nozzle 22 of this embodiment covers a portion of the tail cone 21 from the radially outer side, it may cover the entire tail cone 21 from the radially outer side. Also, in this embodiment, the rear end of the exhaust nozzle 22 is located forward of the rear end of the tail cone 21. However, the rear end of the exhaust nozzle 22 may also be located rearward of the rear end of the tail cone 21, or may be located at the same axial position as the rear end of the tail cone 21.

[0015] As shown in FIG. 2 , the exhaust nozzle 22 of this embodiment includes a nozzle body 31 and a first fixing portion 32. The nozzle body 31 has a cylindrical shape with a cross-sectional area that decreases toward the rear. Furthermore, the nozzle body 31 has a truncated cone shape with the inner diameter of the front portion being larger than the inner diameter of the rear portion. However, the nozzle body 31 does not have to be a strict truncated cone, and the rear end portion may not be circular, and the shape of the nozzle body 31 is not particularly limited. On the other hand, the first fixing portion 32 has an annular shape, is located at the tip portion of the exhaust nozzle 22, and extends radially outward from the front end of the nozzle body 31 in a cross-sectional view. However, the shape of the first fixing portion 32 may be a shape other than an annular shape.

[0016] <Support Casing> The support casing 23 is a member that supports the exhaust nozzle 22. As shown in FIG. 1 , in this embodiment, the casing that forms the bypass flow path 13 functions as the support casing 23. The support casing 23 is located upstream of the exhaust nozzle 22 in the exhaust gas flow direction and has a cylindrical shape. As shown in FIG. 2 , the support casing 23 includes a second fixing portion 36 located in a rear portion. The second fixing portion 36 has an annular shape and protrudes radially outward. However, the shape of the second fixing portion 36 may be a shape other than an annular shape.

[0017] The support casing 23 also supports the exhaust nozzle 22 so that it can move in the front-rear direction. In this disclosure, the "front-rear direction" includes not only the axial direction but also a direction slightly inclined relative to the axial direction. The support casing 23 of this embodiment supports the exhaust nozzle 22 so that it can move in the front-rear direction via an actuator 25, which will be described later. The engine 100 according to this embodiment may further include a plurality of through holes formed in the first fixing portion 32 of the exhaust nozzle 22 and a plurality of rod-shaped members extending rearward from the second fixing portion 36 of the support casing 23 and passing through the through holes. With this configuration, the support casing 23 can support the exhaust nozzle 22 so that it can move in the front-rear direction via the rod-shaped members in addition to the actuator 25. The mechanism that supports the exhaust nozzle 22 so that it can move in the front-rear direction is not limited to the configuration of this embodiment.

[0018] <Variable Nozzle Mechanism> The variable nozzle mechanism 24 includes a first fixed portion 32 of the exhaust nozzle 22, a second fixed portion 36 of the support casing 23, an actuator 25, and an expandable seal 26. Of these, the first fixed portion 32 of the exhaust nozzle 22 and the second fixed portion 36 of the support casing 23 are as described above, so only the actuator 25 and the expandable seal 26 will be described below.

[0019] The actuator 25 is a device that moves the exhaust nozzle 22 in the longitudinal direction relative to the tail cone 21. The type of the actuator 25 is not limited, and may be, for example, an electric type or a hydraulic type. The engine 100 of this embodiment is equipped with a plurality of actuators 25 located at different circumferential positions. However, the number of actuators 25 equipped in the engine 100 is not limited.

[0020] 2 , the actuator 25 of this embodiment has an actuator body 41 and a rod 42 that moves in the front-to-rear direction relative to the actuator body 41. The actuator body 41 is fixed to the second fixing portion 36 of the support casing 23. Meanwhile, the tip portion of the rod 42 is fixed to the first fixing portion 32 of the exhaust nozzle 22. Therefore, when the rod 42 moves in the front-to-rear direction relative to the actuator body 41, the exhaust nozzle 22 moves in the front-to-rear direction relative to the support casing 23, and further, the exhaust nozzle 22 moves in the front-to-rear direction relative to the tail cone 21.

[0021] Although the actuator 25 in this embodiment is attached to the support casing 23, it may also be attached to the exhaust nozzle 22. In this case, for example, the actuator body 41 may be fixed to the first fixing portion 32 of the exhaust nozzle 22, and the rod 42 may be fixed to the second fixing portion 36 of the support casing 23.

[0022] Furthermore, in this embodiment, the variable nozzle mechanism 24 is located radially outward of the exhaust gas flow path 19. Therefore, the variable nozzle mechanism 24 does not interfere with the flow of exhaust gas passing through the exhaust gas flow path 19. Furthermore, since the actuator 25 is not exposed to high-temperature exhaust gas, the actuator 25 is less likely to deteriorate.

[0023] Furthermore, when engine 100 is viewed from the front, variable nozzle mechanism 24 is located inside the outer edge of the portion of engine 100 excluding variable nozzle mechanism 24 (see the two-dot chain line in FIG. 1 ). This makes it possible to prevent the frontal projection area of ​​engine 100 from increasing. In this embodiment, the portion of support casing 23 with the largest outer diameter is located radially outward from the radially outermost portion of variable nozzle mechanism 24. Note that, for example, if equipment is provided on the radially outer portion of engine 100, this equipment is also included in the "portion of engine 100 excluding variable nozzle mechanism 24."

[0024] The expandable seal 26 is a seal located between the exhaust nozzle 22 and the support casing 23. The expandable seal 26 has an annular shape that is continuous in the circumferential direction along the boundary between the exhaust nozzle 22 and the support casing 23. However, the expandable seal 26 may have a shape other than annular. For example, the expandable seal 26 may be discontinuous in the circumferential direction.

[0025] In this embodiment, the front end of the telescopic seal 26, i.e., the upstream end in the exhaust gas flow direction, is fixed to the second fixing part 36 of the support casing 23. However, the front end of the telescopic seal 26 may be fixed to a part of the support casing 23 other than the second fixing part 36. Furthermore, the rear end of the telescopic seal 26, i.e., the downstream end in the exhaust gas flow direction, is fixed to the first fixing part 32 of the exhaust nozzle 22. However, the rear end of the telescopic seal 26 may be fixed to a part of the exhaust nozzle 22 other than the first fixing part 32.

[0026] Furthermore, the expandable seal 26 of this embodiment is expandable in the front-to-rear direction. The expandable seal 26 may be, for example, a bellows seal. Because the expandable seal 26 of this embodiment is expandable in the front-to-rear direction, it can deform in accordance with the movement of the exhaust nozzle 22 in the front-to-rear direction. Therefore, even if the exhaust nozzle 22 moves in the front-to-rear direction, the gap between the exhaust nozzle 22 and the support casing 23 can be sealed, preventing exhaust gas from leaking through that gap.

[0027] <Change in Cross-Sectional Area of ​​Exhaust Gas Flow Passage> Next, a description will be given of a change in the cross-sectional area of ​​the exhaust gas flow passage 19. In this embodiment, the cross-sectional area of ​​the exhaust gas flow passage 19 changes as the exhaust nozzle 22 moves in the front-to-rear direction relative to the tail cone 21. Here, the cross-sectional area of ​​the exhaust gas flow passage 19 refers to the area of ​​a cross section perpendicular to the axial direction at a predetermined axial position of the exhaust gas flow passage 19. The predetermined axial position of the exhaust gas flow passage 19 may be, for example, a position corresponding to the axial center of the tail cone 21, or may be an axial position at which the cross-sectional area of ​​the exhaust gas flow passage 19 is smallest.

[0028] Figure 3 shows the exhaust nozzle 22 in its normal position and its moving position. Hereinafter, the position of the exhaust nozzle 22 indicated by the dashed line in Figure 3 will be referred to as the "normal position," and the position of the exhaust nozzle 22 indicated by the solid line will be referred to as the "moving position." Furthermore, in Figure 3, a predetermined axial position of the exhaust gas flow path 19 is indicated by the symbol X. At the predetermined axial position X of the exhaust gas flow path 19, the inner diameter R2 of the exhaust nozzle 22 when the exhaust nozzle 22 is in the moving position is larger than the inner diameter R1 of the exhaust nozzle 22 when the exhaust nozzle 22 is in the normal position.

[0029] Because the exhaust gas flow passage 19 is a flow passage formed between the exhaust nozzle 22 and the tail cone 21, the cross-sectional area of ​​the exhaust gas flow passage 19 at a predetermined axial position X of the exhaust gas flow passage 19 is determined by the outer diameter of the tail cone 21 and the inner diameter of the exhaust nozzle 22 at the predetermined axial position X of the exhaust gas flow passage 19. Therefore, when the exhaust nozzle 22 moves rearward relative to the tail cone 21, that is, when the exhaust nozzle 22 moves from the normal position to the moved position, the inner diameter of the exhaust nozzle 22 at the predetermined axial position X of the exhaust gas flow passage 19 increases, and therefore the cross-sectional area of ​​the exhaust gas flow passage 19 increases.

[0030] When the exhaust nozzle 22 moves rearward from the movement position, the inner diameter of the exhaust nozzle 22 at the predetermined axial position X of the exhaust gas passage 19 becomes even larger, thereby further increasing the cross-sectional area of ​​the exhaust gas passage 19. On the other hand, when the exhaust nozzle 22 moves forward from the movement position, the inner diameter of the exhaust nozzle 22 at the predetermined axial position X of the exhaust gas passage 19 becomes smaller, thereby reducing the cross-sectional area of ​​the exhaust gas passage 19.

[0031] As described above, in this embodiment, the cross-sectional area of ​​the exhaust gas flow path 19 can be changed by using the actuator 25 to move the exhaust nozzle 22 in the front-to-rear direction relative to the tail cone 21. Therefore, with the engine 100 according to this embodiment, the cross-sectional area of ​​the exhaust gas flow path 19 can be changed even with an exhaust nozzle 22 having a simple configuration.

[0032] (Summary) The first item disclosed in this specification is a gas turbine engine comprising: a tail cone; an exhaust nozzle that covers the tail cone from the radially outer side and forms an exhaust gas flow path between the tail cone and the tail cone; a cylindrical support casing that is located upstream of the exhaust nozzle and supports the exhaust nozzle so that it can move in a forward and backward direction; and an actuator that is attached to the exhaust nozzle or the support casing and that changes the cross-sectional area of ​​the exhaust gas flow path by moving the exhaust nozzle in a forward and backward direction relative to the tail cone.

[0033] According to this configuration, the cross-sectional area of ​​the exhaust gas flow path can be changed even though the exhaust nozzle has a simple structure.

[0034] A second item disclosed in this specification is a gas turbine engine according to the first item, having an upstream end fixed to the support casing and a downstream end fixed to the exhaust nozzle, and including an expandable seal that is expandable in the forward and backward directions.

[0035] With this configuration, even if the exhaust nozzle moves in the front-rear direction, it is possible to prevent exhaust gas from leaking from the gap between the exhaust nozzle and the support casing.

[0036] A third item disclosed in this specification is the gas turbine engine described in the second item, in which a variable nozzle mechanism including the actuator, the telescopic seal, a first fixing portion of the exhaust nozzle to which the telescopic seal is fixed, and a second fixing portion of the support casing to which the actuator and the telescopic seal are fixed is located radially outward from the exhaust gas flow path.

[0037] With this configuration, the variable nozzle mechanism does not interfere with the flow of exhaust gas passing through the exhaust gas flow passage.

[0038] A fourth item disclosed in this specification is the gas turbine engine according to the third item, wherein the variable nozzle mechanism is located inside an outer edge of a portion of the gas turbine engine excluding the variable nozzle mechanism when viewed from the front of the gas turbine engine.

[0039] This configuration can prevent the front projection area of ​​the engine from increasing.

[0040] 21 tail cone 22 exhaust nozzle 23 support casing 24 variable nozzle mechanism 25 actuator 26 expandable seal 32 first fixed part 36 second fixed part 100 gas turbine engine

Claims

1. A gas turbine engine comprising: a tail cone; an exhaust nozzle covering the tail cone from the radially outside and forming an exhaust gas flow path between the tail cone and the tail cone; a cylindrical support casing located upstream of the exhaust nozzle and supporting the exhaust nozzle so that the exhaust nozzle can move in a forward and backward direction; and an actuator attached to the exhaust nozzle or the support casing and changing the cross-sectional area of ​​the exhaust gas flow path by moving the exhaust nozzle in a forward and backward direction relative to the tail cone.

2. A gas turbine engine as claimed in claim 1, further comprising an expandable seal, the expandable seal having an upstream end fixed to said supporting casing and a downstream end fixed to said exhaust nozzle, the expandable seal being expandable in a fore-and-aft direction.

3. A gas turbine engine as described in claim 2, wherein a variable nozzle mechanism including the actuator, the expandable seal, a first fixed portion of the exhaust nozzle to which the expandable seal is fixed, and a second fixed portion of the supporting casing to which the actuator and the expandable seal are fixed is located radially outward from the exhaust gas flow path.

4. A gas turbine engine according to claim 3, wherein the variable nozzle mechanism is located inside the outer edge of the portion of the gas turbine engine excluding the variable nozzle mechanism when the gas turbine engine is viewed from the front.

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