Device for sealing and reinjecting a bypass flow for a turbine nozzle

Abstract

The invention relates to a turbine (9) comprising a sealing device (18) connected to a nozzle (17) having a radial degree of freedom. The sealing device (18) comprises a reinjection duct configured to collect fluid present in a cavity (43) located between the tongues and formed by the sealing device (18) and configured to reinject the fluid collected in this way into the main duct (11A) at a speed having a large axial component.

Description

Technical Field

[0001] This invention relates to the field of turbine engines, particularly for use in aircraft propulsion units. Background Technology

[0002] A conventional turbine engine turbine comprises one or more stages, each stage consisting of a nozzle and a movable wheel equipped with a platform, the platforms radially defining a main flow path for fluid flow. The nozzle of one stage is configured to accelerate the fluid and deflect it in the direction of the blades of the movable wheel in the same stage, thereby driving the blades to rotate.

[0003] To reduce the flow rate of fluids that tend to bypass the nozzle and flow out of the main flow path, it is known to install a sealing device at the root of the nozzle, as described in document FR3027343A1.

[0004] Bypass fluid, often referred to as "bypass," returns to the main flow path after passing through this sealed device, resulting in mixing losses and thus reducing turbine performance and efficiency. Summary of the Invention

[0005] To improve the performance and efficiency of a turbine engine turbine, the present invention provides a turbine engine nozzle extending about a longitudinal axis and comprising a platform, blades extending radially outward from the platform relative to the longitudinal axis, a main flange extending radially inward from the platform, a wear-resistant element, and a support element supporting the wear-resistant element. The support element includes a flange connected to the main flange. The wear-resistant element is designed to be arranged opposite two scraping portions carried by the rotor of the turbine engine, and a scraping portion cavity is defined between the two scraping portions. According to the invention, the nozzle includes a re-injection conduit comprising an inlet and an outlet. The inlet is configured to open into the scraping portion cavity, and the outlet is formed at the radially outer end of the flange of the support element and configured to open into a cavity extending axially downstream of the nozzle. The re-injection conduit includes a section extending within the flange of the support element.

[0006] During operation, bypass fluid enters the scraper cavity. Due to the pressure difference between the scraper cavity and the cavity downstream of the nozzle (connected to the main flow path), a portion of the bypass fluid passes through the reinjection pipe.

[0007] The positioning of the pipe outlet at the radially outer end of the flange of the support element allows the bypass fluid to be reinjected into the main flow path radially closer to it.

[0008] Therefore, this invention enables the reduction of mixing losses, which allows for improved turbine performance and efficiency.

[0009] This invention also allows for simplified nozzle manufacturing, particularly the machining of re-injection channels.

[0010] Preferably, the section of the reinjection pipe is straight.

[0011] In one embodiment, the re-injection conduit includes an inlet section that passes through the wear-resistant element.

[0012] Preferably, the inlet section is straight.

[0013] Generally, the presence of straight sections in the re-injection pipe allows for simplified machining of the re-injection pipe.

[0014] In one embodiment, the inlet section defines an inlet direction perpendicular to the outlet direction, or forms an angle of approximately 90° with the outlet direction.

[0015] In one embodiment, the re-injection conduit includes an axially extending outlet section.

[0016] Therefore, the axial orientation of the outlet section allows the bypass fluid to be reinjected into the main flow path, thereby minimizing mixing losses with the fluid flowing in the main flow path.

[0017] The outlet section of the re-injection pipe can have an outlet direction parallel to the longitudinal axis in order to maximize the axial component of the velocity of the re-injection flow.

[0018] Alternatively, the outlet direction can be inclined relative to the longitudinal axis, such that the outlet section extends both axially and radially. In this case, considering a plane passing through the longitudinal axis and through the intersection of the outlet direction and the re-injection pipe outlet section, the angle between the outlet direction and the longitudinal axis is preferably relatively small, for example, less than 20°, so that the radial component is relatively small compared to the axial component of the velocity of the re-injection flow.

[0019] In one embodiment, the outlet section of the re-injection pipe extends tangentially relative to the longitudinal axis.

[0020] The tangential orientation of the outlet section allows the bypass fluid to be reinjected into the main flow path, while increasing the tangential component of the velocity of the fluid exiting the reinjection pipe, wherein the rotation direction of the fluid exiting the reinjection pipe is the same as that of the mainstream fluid flowing in the main flow path.

[0021] This allows for further reduction in mixing losses, thereby improving turbine performance and efficiency.

[0022] In one embodiment, the outlet section of the re-injection pipe has a cross-section that decreases toward the outlet.

[0023] Therefore, the outlet section can form a cavity that converges toward the outlet, thereby allowing for accelerated flow from the re-injection pipe.

[0024] Preferably, the cross-section of the outlet section decreases monotonically toward the outlet.

[0025] In one embodiment, the flange of the support element includes a downstream surface and an element that protrudes from the downstream surface and forms the outlet section of the reinjection pipe.

[0026] The component may be fixed to the flange or integrally formed with the flange.

[0027] In one embodiment, the support element is connected to the main flange, thereby enabling the support element to move radially relative to the main flange.

[0028] In one embodiment, the flange of the support element is a downstream flange, the support element includes an upstream flange, and the main flange of the nozzle extends axially between the upstream flange and the downstream flange of the support element.

[0029] In one embodiment, the nozzle includes a heat-protected metal plate fastened to the downstream flange of a support element.

[0030] In a variation of this embodiment, the nozzle further includes another heat-protected metal plate fastened to the upstream flange of the support element, such that the re-injection conduit extends axially between the two metal plates.

[0031] In one embodiment, the blade has a trailing edge that defines an outlet line, the outlet of which extends in a continuation of the re-injection conduit.

[0032] In other words, the outlet of the re-injection pipe can be located in the wake of the blade trailing edge, essentially in a straight line with the blade trailing edge.

[0033] The pressure in the trailing edge wake of a blade is lower than the pressure in the circumferentially adjacent region (i.e., extending circumferentially between the trailing edges of two adjacent blades).

[0034] Positioning the re-injection pipe outlet in the trailing edge of the blade increases the pressure differential between the pipe inlet and outlet.

[0035] In one embodiment, the support element of the sealing device is annular.

[0036] Another object of the present invention is a turbine for a turbine engine, the turbine including the nozzles as described above.

[0037] In one embodiment, the turbine is a low-pressure turbine.

[0038] In one embodiment, the turbine includes a movable wheel extending axially downstream of the nozzle, the movable wheel including a spoiler, and the outlet of the re-injection pipe of the nozzle opening radially above the spoiler.

[0039] Another object of the present invention is a turbine engine for an aircraft propulsion system, comprising such a turbine.

[0040] According to another aspect, the object of the present invention is a method for manufacturing a nozzle as described above.

[0041] In one embodiment, the method includes the step of machining the support element of the sealing device to form a reinjection conduit.

[0042] Other advantages and features of the invention will become apparent upon reading the following detailed, non-limiting description. Attached Figure Description

[0043] The following detailed description refers to the accompanying drawings, in which:

[0044] [ Figure 1 [This is a schematic longitudinal cross-sectional view of the aircraft's propulsion unit;]

[0045] [ Figure 2 [This is a partial schematic longitudinal section half-view of the turbine of the turbine engine according to the present invention;]

[0046] [ Figure 3 [Illustrated perspective view of the circumferential portion of the sealing device according to the invention, showing the support element and wear-resistant element forming the reinjection channel;]

[0047] [ Figure 4 It is based on the cross-section of a portion passing through the re-injection pipe. Figure 3 A schematic longitudinal cross-sectional view of the sealing device;

[0048] [ Figure 5 ]yes Figure 3 A schematic diagram of the circumferential portion of the support element of the sealing device. Detailed Implementation

[0049] The accompanying figures include reference frames L, R, and C that define mutually orthogonal longitudinal / axial, radial, and circumferential / tangential directions, respectively.

[0050] Figure 1 The aircraft propulsion unit 1 is shown, including a turbine engine 2 rectified by a nacelle 3. In this example, the turbine engine 2 is a twin-shaft turbofan engine.

[0051] The terms “upstream” and “downstream” will be defined below with respect to the direction S1 of the airflow passing through the propulsion unit 1 when the propulsion unit 1 is propelled.

[0052] The turbofan engine 2 has a longitudinal central axis A1 around which the components of the turbofan engine extend. In this example, these components, from upstream to downstream, are a fan 4, a low-pressure compressor 5, a high-pressure compressor 6, a combustion chamber 7, a high-pressure turbine 8, and a low-pressure turbine 9. Compressors 5 and 6, combustion chamber 7, and turbines 8 and 9 form a gas generator.

[0053] During operation, the airflow 10 enters the propulsion unit 1 through the air inlet upstream of the nacelle 3, passes through the fan 4, and then splits into a central main flow 10A and a secondary flow 10B. The main flow 10A flows in the main gas flow path 11A that passes through the gas generator. Subsequently, the secondary flow 10B flows in the secondary flow path 11B that surrounds the gas generator and is radially directed outward from the nacelle 3.

[0054] Low-pressure turbine 9 (partially as) Figure 2 The turbine (shown) is configured to recover some of the combustion energy to drive the movable wheels forming the rotor of the turbine 9 to rotate about axis A1. Between each pair of adjacent movable wheels, the turbine 9 includes a bladed stator crown forming a guide vane assembly.

[0055] Figure 2 The image shows two movable wheels 15 and 16, as well as a turbine 9.

[0056] The nozzle 17 extends axially between the movable wheel 15 that forms the upstream wheel and the movable wheel 16 that forms the downstream wheel.

[0057] In a manner known per se, each of the movable wheels 15 and 16 includes a disc 20 and a blade 21 carried by the disc 20.

[0058] In this example, the disk 20 of the upstream wheel 15 includes a shroud 22 extending axially in the direction of the downstream wheel 16, the shroud 22 being radially inward of the guide vane assembly 17. The downstream end of the shroud 22 is connected to the disk 20 of the downstream wheel 16 to secure the wheels 15 and 16, which rotate about axis A1, together with each other.

[0059] In this example, nozzle 17 includes a plurality of fan-shaped portions arranged circumferentially end to end to form together the bladed crown.

[0060] In a manner known per se, each sector of nozzle 17 includes a platform 25, a blade 26, and a flange 27. The platform 25 defines a portion of the main flow path 11A radially inward, the blade 26 extends radially outward from the platform 25 and is circumferentially spaced around axis A1, and the flange 27 extends radially inward from the platform 25.

[0061] The nozzle 17 also includes a sealing device 18, which includes a wear-resistant element 30, also known as a wear component, a support element 31, and two scraping parts 32.

[0062] Each of the wear-resistant element 30, the support element 31, and the scraping part 32 forms an annular component with an axis A1.

[0063] The support element 31 includes an axial portion 35 and an upstream flange 36 and a downstream flange 37, each extending radially outward from the axial portion 35.

[0064] The axial portion 35 of the support element 31 defines the inner surface on which the wear-resistant element 30 is fastened.

[0065] The flanges 36 and 37 of the support element 31 axially define a space between them that receives the flange 27 of each sector of the nozzle 17. The width of this space substantially corresponds to the width of the flange 27 of each sector, so as to lock the axial position of the support element 31 relative to the nozzle 17.

[0066] In this example, the position of the support element 31 is also locked circumferentially, but it can move freely radially relative to the flange 27 of the nozzle 17.

[0067] For this purpose, in this example, the flange 27 of each sector of the nozzle 17 includes a radial hole in which a pin 38 can slide radially, and the pin 38 is tightly fitted in the corresponding orifice of each flange in the flanges 36 and 37.

[0068] Of course, multiple pins distributed around axis A1 can be implemented and mate with flanges 27, 36 and 37 similarly used for each sector of nozzle 17.

[0069] Therefore, the support element 31 is connected to the flange 27 so that the support element and the flange can move radially relative to each other. It should be understood that this freedom of movement can be ensured by any other sliding device.

[0070] exist Figure 2 In the example, the scraping part 32 of the sealing device 18 is carried by the protective cover 22.

[0071] During operation, the movable wheels 15 and 16 are driven to rotate about axis A1, which causes the scraping part 32 to rub against the wear-resistant element 30, which in this example has a honeycomb structure.

[0072] Therefore, device 18 ensures a dynamic seal, thereby reducing the bypassing of the main flow 10A in the radial interior of nozzle 17.

[0073] Figure 2 The nozzle 17 also includes heat-protected metal plates 65 and 67 supported by flanges 37 and 36, respectively.

[0074] More specifically, the present invention relates to an apparatus for re-injecting a portion of the bypass flow through the sealing device 18 into the main flow path 11A.

[0075] exist Figures 2 to 4 In one embodiment, the sealing device 18 forms a re-injection conduit 40 that passes through the wear-resistant element 30 and the support element 31.

[0076] The conduit 40 includes an inlet 41 that opens onto the inner surface 42 of the wear-resistant element 30, which in this case corresponds to the friction surface of the scraping portion 32.

[0077] Axially, the inlet 41 of the conduit 40 extends between the two scraping portions 32, thus opening into the scraping portion inter-cavity 43, which is defined axially upstream by one of the scraping portions 32, axially downstream by the other scraping portion 32, radially inward by a shield 22, and radially outward by a wear-resistant element 30 (see...). Figure 2 ).

[0078] The conduit 40 extends radially from the inlet 41 through the wear-resistant element 30 until it reaches the intermediate cavity 45 formed in the axial portion 35 of the support element 31.

[0079] The portion of the pipe 40 extending between the inlet 41 and the intermediate cavity 45 forms a straight inlet section 46, which in this example has an axis A2 perpendicular to the axis A1.

[0080] exist Figure 3 and Figure 4 In one embodiment, the support element 31 includes an element 39 forming a protrusion that axially protrudes from the downstream flange 37 at one end of the downstream flange 37 that is radially opposite to the axial portion 35.

[0081] The conduit 40 includes an outlet 47 that opens onto the downstream surface 48 of the protrusion 39 and thus at the radially outer end of the flange 37.

[0082] Between the intermediate cavity 45 and the outlet 47, the conduit 40 includes a straight section 49 extending radially through the downstream flange 37 and an outlet section 50 extending axially and tangentially through the protrusion 39.

[0083] In this example, the outlet section 50 has an axis A3 that is parallel to axis A1 and perpendicular to axis A2 and axis A4 of section 49.

[0084] Reference Figure 3 and Figure 5 The protrusion 39 of the outlet section 50 of the pipe 40 is oriented in the circumferential direction such that the axis A3 intersects the plane PA1 containing the axis A1.

[0085] In this example, axis A3 and plane PA1 form an angle B1 between 40° and 90°.

[0086] Given this circumferential orientation of the outlet section 50, the inlet 41 and outlet 47 of the pipe 40 have different circumferential positions relative to each other around axis A1.

[0087] Reference Figure 2 The protrusion 39 is configured such that the outlet 47 of the conduit 40 leads to the cavity 51, which extends downstream of the flange 27 of the nozzle 17 and is fluidly connected to the main flow path 11A.

[0088] In this example, the outlet 47 of the pipe 40 opens radially above the spoiler 60 of the movable wheel 16, which extends axially toward the front of the movable wheel 16 along the direction of the nozzle 17.

[0089] Under the pressure difference between the cavity 51 and the scraper cavity 43, a portion of the bypass fluid present in the scraper cavity 43 is drawn into the pipe 40 through the inlet 41 and discharged through the outlet 47.

[0090] Therefore, the fluid portion is re-injected into cavity 51 and thus into the main flow path 11A, resulting in a velocity with large axial and tangential components, which enables a significant reduction in mixing losses.

[0091] In order to accelerate the fluid coming out of the reinjection pipe 40, the outlet section 50 of the reinjection pipe 40 has a cross section that decreases monotonically toward the outlet 47, thereby forming a converging outlet cavity.

[0092] In this example, the protrusion 39 is configured such that the outlet 47 of the reinjection conduit 40 extends in a continuation of the trailing edge of one of the blades 26 of the nozzle 17, in order to enhance the pressure differential between the cavity 43 and the cavity 51.

[0093] Of course, the present invention is not limited to the examples and embodiments described above. The present invention also specifically covers many geometries of the re-injection pipe 40 and / or support element 31 and / or wear-resistant element 30 and / or scraping part 32 and / or the relative positions of these different components relative to each other.

[0094] For example, sections 46 and / or 49 and / or 50 of the reinjection pipe 40 may have a circular, oval, or rectangular cross-section.

[0095] In an embodiment not shown, the sealing device includes two or more scraping portions, and the re-injection conduit has an inlet leading to a cavity defined by a first scraping portion and a second scraping portion and / or an inlet leading to a cavity defined by a second scraping portion and a third scraping portion.

[0096] In addition, the device may include a plurality of re-injection channels 40, such as the re-injection channels described above, which may be distributed circumferentially around axis A1, such that each re-injection channel extends below the corresponding blade 26 of nozzle 17.

[0097] Furthermore, the present invention can be implemented in a turbine different from the turbine described above, for example, in a high-pressure turbine 8.

[0098] Finally, it should be noted that the support element 31 is connected to the flange 27 so that the support element and the flange can move radially relative to each other. It should be understood that this freedom of movement can be ensured by any other sliding device. Thus, separation is achieved between the angular sector of the nozzle, comprising the platform sector 25, blade 26, and main flange 27 on one side, and the assembly comprising the wear-resistant element 30 and the element support 31 (which is preferably annular and non-sectoral, and for example, integrally formed) on the other side. Due to the annular and non-sectoral nature of the aforementioned elements, this embodiment prevents leakage in the space between the sector portions of the nozzle. Therefore, the main blade flange 27 is fitted between elements 36 and 37 and can move radially without driving the annular and non-sectoral elements. Thus, the radial movements of these different components are advantageously separated.

[0099] Therefore, in this invention, the position of the re-injection conduit 40 is independent of the radial movement of the blades and the radial movement of the nozzle angular sector in which these blades are integrated. This allows for control of leakage in the space between the sector sections, as well as leakage at the labyrinth seal in which the scraper section 32 is integrated.

Claims

1. A nozzle (17) of a turbine engine (2), the nozzle extending about a longitudinal axis (A1) and comprising a platform (25), blades (26) extending radially outward from the platform (25) relative to the longitudinal axis (A1), a main flange (27) extending radially inward from the platform (25), a wear-resistant element (30), and a support element (31) supporting the wear-resistant element (30), the support element (31) comprising a flange (37) connected to the main flange (27), the wear-resistant element (30) being intended to be arranged opposite to two scraping portions (32) carried by the rotor of the turbine engine (2), the two scraping portions defining a scraping portion cavity (43), characterized in that, The nozzle includes a re-injection conduit (40) comprising an inlet (41) and an outlet (47), the inlet being configured to lead to the scraping cavity (43), the outlet being formed at the radially outer end of the flange (37) of the support element (31) and configured to lead to a cavity (51) extending axially downstream of the nozzle (17), the re-injection conduit (40) including a segment (49) extending in the flange (37) of the support element (31).

2. The nozzle (17) according to claim 1, wherein, The section (49) of the re-injection pipe (40) is straight.

3. The nozzle (17) according to claim 1 or 2, wherein, The re-injection conduit (40) includes a straight inlet section (46) that passes through the wear-resistant element (30).

4. The nozzle (17) according to claim 1 or 2, wherein, The re-injection conduit (40) includes an outlet section (50) that extends axially.

5. The nozzle (17) according to claim 4, wherein, The flange (37) of the support element (31) includes a downstream surface and an element (39) that protrudes from the downstream surface and forms the outlet section (50) of the re-injection pipe (40).

6. The nozzle (17) according to claim 1 or 2, wherein, The flange (37) of the support element (31) is a downstream flange, the support element (31) includes an upstream flange (36), and the main flange (27) of the nozzle (17) extends axially between the upstream flange (36) and the downstream flange (37) of the support element (31).

7. The nozzle (17) according to claim 6, wherein the nozzle comprises a first heat-protected metal plate (65) fastened to the downstream flange (37) of the support element (31).

8. The nozzle (17) according to claim 1 or 2, wherein, The blade (26) has a trailing edge that defines an outlet line, and the outlet (47) of the re-injection conduit (40) extends in a continuation of the line.

9. The nozzle (17) according to claim 1 or 2, wherein, The support element (31) is connected to the main flange (27) so that the support element and the main flange can move radially relative to each other.

10. The nozzle (17) according to claim 4, wherein, The outlet section extends tangentially relative to the longitudinal axis (A1).

11. The nozzle (17) according to claim 7, wherein the nozzle includes a second heat-protected metal plate (67) fastened to the upstream flange (36) of the support element (31) such that the re-injection conduit (40) extends axially between the first heat-protected metal plate and the second heat-protected metal plate.

12. A turbine (9) for a turbine engine (2), comprising a nozzle (17) according to any one of claims 1 to 11.

13. The turbine (9) according to claim 12, comprising a movable wheel (16) extending axially downstream of the nozzle (17), the movable wheel (16) including a spoiler (60), the outlet (47) of the re-injection conduit (40) of the nozzle (17) opening radially above the spoiler (60).

14. A method for manufacturing a nozzle (17) according to any one of claims 1 to 11, comprising the step of machining the support element (31) to form the re-injection conduit (40).

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