Blade configured to be mounted on a bladed wheel of an aircraft turbine engine, bladed wheel of an aircraft turbine engine and turbine engine for an aircraft

Abstract

The invention relates to a blade (3) mounted on a bladed wheel (20) of an aircraft turbine engine (1) and including an airfoil (33), a root (31) mounted in a groove of a disk, a platform (32) and a heel (34) from which upstream (340) and downstream (341) ridges extend radially outward. A dynamic damping device (5) is positioned at a location on the heel (34) in order to cooperate through friction with a side face (30') of an adjacent blade (3') and dampen dynamic loads at the heel. A cavity (51, 51') is formed in one of the ridges and opens onto the side face of the heel facing a side face of the adjacent blade when the blade is mounted on the disk. A friction element (50, 50') is movably mounted at least partially in the cavity between a contact friction position and a spaced position away from the side face of the adjacent blade.

Description

[0001] DESCRIPTION

[0002] TITLE: BLADE COMPRISING A DYNAMIC DAMPING DEVICE, BLADED WHEEL AND CORRESPONDING TURBOMACHINE.

[0003] Scope of the invention

[0004] The present invention relates to the field of aircraft turbomachinery, and more specifically to the design of bladed wheels forming the turbines and compressors of these turbomachines.

[0005] It relates more specifically to the dynamic damping by friction of the blades, which follow one another in the circumferential direction to form an annular row of blades.

[0006] The invention applies to all turbomachine designs, for example turbojets with a fan driven directly by a low-pressure body, or driven indirectly by a reducer.

[0007] Prior art

[0008] Aircraft turbomachinery compressors and turbines consist of an axial arrangement of fixed and rotating bladed wheels, also known as stator and rotor bladed wheels. When such a bladed wheel is angularly segmented, that is, along the wheel's circumferential direction, it is usually necessary to limit the vibrational stresses on the blades arranged adjacently along the wheel's circumferential direction.

[0009] To achieve this, methods are implemented to ensure dynamic damping of these sectors by dissipating resonance energy through friction between the blade roots. Such a damping solution is, for example, described in document FR 3 085 712 A1.

[0010] Another, more conventional solution involves implementing a contact friction technology between the heels of adjacent blades with specific shapes. This technology, also known as "pretorsion," is characterized by a specific cut on the two opposing circumferential faces of the heel, with a protrusion on the upper surface and a complementary shape on the lower surface. The paired interaction of these circumferential faces allows the two adjacent heels to be held relative to each other in the axial direction. This pretorsion technology is also referred to by the English term "interlock."

[0011] During blade assembly, the circumferential contact faces are pressed together by means of an angular deformation of the blade, creating the desired pretorsion. In operation, blade vibrations induce relative sliding at the circumferential surfaces of the blade ends, which, coupled with contact pressures, creates friction damping.

[0012] With this technology, the contact force between the blade tips can vary during turbomachine operation. This variation can result from the natural rotation of the blade around its twist axis (clockwise or counterclockwise), or from the relative movement of adjacent tips in the circumferential direction (moving closer together or further apart). During blade assembly, it is necessary to take these potential variations into account during operation and to ensure that the target contact force is achieved at high speeds, i.e., the speed at which dynamic damping is primarily desired. This can lead to applying a very high contact force during blade assembly, resulting in significant static overstresses that can weaken the blades and / or reduce their lifespan. This drawback is more or less significant depending on the material used and its ability to withstand such stresses.For example, with blades made of ceramic matrix composite material, also known as CMC material, the permissible mechanical deformations are often small, making the blades less tolerant of this pretorsion principle. Thus, positioning the blades on the wheels becomes problematic because it typically requires significant deformation to position all the blades circumferentially. Furthermore, when a blade is made of CMC material, it may be incompatible with the need to apply high pretorsion to the assembly, which is required for satisfactory damping at the desired operating speed.

[0013] Other dynamic damping solutions are known, such as adding friction elements to the interface between the heels, at the level of their circumferential faces which cooperate in pairs. These solutions generally have the disadvantage of generating aerodynamic disturbances at the level of the groove.

[0014] Description of the invention

[0015] The invention aims to remedy at least in part the aforementioned drawbacks relating to prior art techniques.

[0016] To this end, the invention relates to a blade configured to be mounted on a bladed wheel of an aircraft turbomachine, said bladed wheel comprising a disc on which said blade is intended to be mounted so that several blades follow one another in a circumferential direction of said bladed wheel so as to form an annular row of blades, said blade comprising: a blade having an aerodynamic profile; a foot extending at a radially internal end of said blade and configured to be mounted in a groove which opens at the external periphery of the disc; a radially internal platform separating said blade from said foot; a heel extending at a radially external end of said blade, said heel comprising a radially external platform from which extend radially outwards an upstream blade and a downstream blade.

[0017] According to the invention, said blade further comprises a dynamic damping device positioned at the location of said heel and configured to cooperate by friction with a lateral face of a circumferentially adjacent blade so as to dampen dynamic stresses at the level of said heel.

[0018] The invention thus provides a simple, reliable, efficient and low mass solution to the problems previously outlined, and whose principle makes it possible to create a damping of dynamic stresses at the level of the heel while freeing itself from the constraints of prior art solutions.

[0019] Furthermore, by duplicating the principle of the invention on several sets of two adjacent blades of the wheel, or even on the entire bladed wheel, it is possible to reduce the axial leakage section on the entire bladed wheel and thus improve the performance of the stage.

[0020] According to a particular aspect of at least one embodiment of the invention, said heel comprises a housing hollowed out in one of said upstream and downstream slits and opening at the level of said lateral face of said heel so as to be positioned opposite said lateral face of said circumferentially adjacent blade when said blade is mounted on the disc, and said dynamic damping device comprises a friction element mounted movably in said housing between: a friction position in which said friction element is at least partly in said housing, and is in contact with said lateral face of said circumferentially adjacent blade when said blade is mounted on said disc, so that said friction element cooperates by friction with said lateral face of said circumferentially adjacent blade;a position set apart in which said rubbing element is at least partly in said housing, and is at a distance from said lateral face of said blade circumferentially adjacent when said blade is mounted on said disc.;

[0021] According to a particular aspect of at least one embodiment of the invention, the friction element is made from a ceramic material or a ceramic matrix composite material. According to a particular aspect of at least one embodiment of the invention, the friction element has a shape defined by a maximum dimension DI and a minimum dimension D2, with a ratio between the maximum dimension DI and the minimum dimension D2 less than or equal to 10, preferably less than or equal to 5. According to a particular aspect of at least one embodiment of the invention, the friction element has a cylindrical shape, an ellipsoidal shape, or a triangular shape. According to a particular aspect of at least one embodiment of the invention, the housing is hollowed out by electrical discharge machining (EDM).

[0022] According to a particular aspect of at least one embodiment of the invention, said housing is hollowed out in a direction inclined with respect to a direction tangential to said heel.

[0023] According to a particular aspect of at least one embodiment of the invention, said dynamic damping device comprises a second formed housing opening into the other of said upstream and downstream blades such that said second housing opens at the level of said lateral face of said heel, and said dynamic damping device further comprises a second friction element mounted movably in said second housing between: a friction position in which said second friction element is at least partly in said second housing, and is in contact with said lateral face of said circumferentially adjacent blade when said blade is mounted on said disc, so that said second friction element cooperates by friction with said lateral face of said circumferentially adjacent blade;a set-apart position in which said second rubbing element is at least partly in said second housing, and is circumferentially adjacent to said lateral face of said blade when said blade is mounted on said disc.;

[0024] The invention also relates to a bladed wheel for an aircraft turbomachine, said bladed wheel comprising a disc and several blades according to one of the aforementioned embodiments mounted on said disc, the blades following one another in a circumferential direction of said bladed wheel so as to form an annular row of blades. Furthermore, for two given blades, a first of said two blades comprises a dynamic damping device positioned at said root and configured to cooperate by friction with a circumferentially adjacent lateral face of said second of the two blades so as to dampen dynamic stresses at said root of said first of said two blades.

[0025] The invention also relates to an aircraft turbomachine comprising a bladed wheel according to the aforementioned embodiment.

[0026] Presentation of the figures

[0027] The invention, as well as the various advantages it presents, will be more easily understood in the light of the following description of an illustrative and non-limiting embodiment thereof, and the accompanying drawings, among which: [Fig. 1] illustrates a schematic longitudinal cross-sectional view of an aircraft turbomachine according to the invention;

[0028] [Fig. 2] illustrates a more detailed perspective view of a bladed wheel of a low-pressure turbine of the turbomachine according to a first embodiment of the invention;

[0029] [Fig. 3] and [Fig. 4] illustrate in perspective a portion of a blade according to a first embodiment of the invention;

[0030] [Fig. 5] and [Fig. 6] illustrate in perspective a portion of a sealing element according to a first embodiment of the invention;

[0031] [Fig. 7] is a cross-sectional view of a portion of a blade according to the first embodiment of the invention;

[0032] [Fig. 8], [Fig. 9] and [Fig. 10] are perspective views of a portion of a bladed wheel illustrating two blades according to the first embodiment of the invention, showing different positions of the sealing element;

[0033] [Fig. 11] illustrates in perspective a portion of a sealing element according to a second embodiment of the invention;

[0034] [Fig. 12], [Fig. 13] and [Fig. 14] illustrate in perspective a portion of a blade according to a second embodiment of the invention, and

[0035] [Fig. 15] and [Fig. 16] illustrate in perspective a portion of a blade according to a third embodiment of the invention.

[0036] Detailed description of an embodiment of the invention

[0037] With reference first to Figure 1, an aircraft turbomachine 1 is shown, according to a preferred embodiment of the invention. This is a twin-spool, turbofan engine. However, it could be a turbomachine of another type, for example a turboprop, without departing from the scope of the invention.

[0038] The turbomachine 1 has a central longitudinal axis 2 around which its various components extend. It comprises, from upstream to downstream along a main direction 5 of gas flow through this turbomachine, a blower 30, a low-pressure compressor 4, a high-pressure compressor 6, a combustion chamber 11, a high-pressure turbine 7 and a low-pressure turbine 8. The blower 30 can be driven directly by a low-pressure unit comprising the compressor 4 and the turbine 8, or indirectly by a reduction gear (not shown).

[0039] Conventionally, after passing through the blower 30, the air splits into a central primary flow 12a and a secondary flow 12b that surrounds the primary flow. The primary flow 12a flows into a main gas circulation channel 14a, passing through the compressors 4, 6, the combustion chamber 11, and the turbines 7, 8. The secondary flow 12b flows into a secondary channel 14b, radially delimited outwards by an engine casing, surrounded by a nacelle 9. Each turbine 7, 8 and each compressor 4, 6 comprise, in a conventional manner known to those skilled in the art, an alternation of movable and fixed bladed wheels, centered on the axis 2. The invention lies in the design of these bladed wheels, and more particularly in the dynamic damping principle implemented therein.

[0040] We now present, in relation to Figure 2, a first embodiment of a bladed wheel 20, and in relation to Figures 3 to 10, a first embodiment of a blade. This wheel is preferably intended to form part of the low-pressure turbine 8. However, the invention can be applied to the high-pressure turbine 7, or to one of the two compressors 4, 6. Furthermore, it can be a fixed bladed wheel, without departing from the scope of the invention.

[0041] The bladed wheel 20 comprises a disc 22, centered on the axis 2 and on which are mounted, radially outwards, a plurality of distinct blades 3 forming an annular row of blades.

[0042] As illustrated in Figure 2, and partially in Figures 3 and 4, each blade 3 comprises: a blade 33 having an aerodynamic profile; a foot 31 extending at a radially internal end of the blade 33 and configured to be mounted in a groove which opens at the external periphery of the disc 22; a radially internal platform 32 separating the blade 33 from the foot 31; a heel 34 extending at a radially external end of the blade 33, this heel 34 comprising a radially external platform 40 from which extend radially outwards an upstream scraper 340 and a downstream scraper 341.

[0043] According to the invention, the blade 3 further comprises a dynamic damping device positioned at the location of the heel 34 and configured to cooperate by friction with a lateral face of a circumferentially adjacent blade 3A, as illustrated in particular in figures 8 to 10, so as to dampen dynamic stresses at the level of said heel 34.

[0044] More particularly, in this embodiment, the dynamic damping device includes a friction element 50 mounted movably in a housing 51 formed opening onto a lateral face of the heel 34 so as to be positioned opposite the lateral face of the circumferentially adjacent blade 3A when the blade 3 is mounted on the bladed wheel 20.

[0045] Here, and as illustrated more specifically in Figures 3 and 4, the housing 51 is cut into the downstream slot 341 so that this housing opens at the level of the lateral face of the heel. However, according to other embodiments, the housing could be cut into one of the upstream and downstream slots. Alternatively, a housing could be cut into each of the two slots, as shown later in connection with the second embodiment.

[0046] As can be seen more particularly in figure 7, this housing 51 has a roughly rectangular parallelepiped shape and is hollowed out in a direction inclined relative to a direction tangential to the heel 34.

[0047] In other words, in this embodiment housing 51 forms a non-zero angle with a horizontal plane of the blade foot.

[0048] Depending on the embodiment, this angle can be between 25° and 65° relative to a horizontal plane of the blade foot.

[0049] Such a range has the advantage of allowing the friction element to slide within the housing and preventing the housing from becoming stuck. In other words, this range of values ​​allows for a compromise between, on the one hand, the damping effect of the lateral force, and on the other hand, the radial bulk of the blade due to the angle of the housing and the friction element.

[0050] It should be noted that housing 51 can, preferably, be excavated by sinking using electro-erosion.

[0051] This friction element is mounted movably in the housing 51 between: a friction position in which this friction element 50 is at least partly in the housing 51, and is in contact with the lateral face of the circumferentially adjacent blade 3A when the blade 3 is mounted on the disk 22, so that the friction element 50 cooperates by friction with the lateral face of the circumferentially adjacent blade 3A; a distanced position in which the friction element 50 is at least partly in the housing 51, and is at a distance from the lateral face of the circumferentially adjacent blade 3A when said blade 3 is mounted on the disk 22.

[0052] This friction element is therefore mounted freely at least along one axis of rotation and along one axis of translation so as to be able to move between the friction position and the offset position.

[0053] This housing 51 is calibrated in depth, and also in relation to the friction element 50, in order to guarantee the retention of the friction element regardless of the relative movement of the blades with respect to each other and in order to guarantee the free movement of the friction element in the housing 51.

[0054] Thus, for the bladed wheel 20 of an aircraft turbomachine 1, for two given adjacent blades 3, 3A, one of the two blades 3 includes a dynamic damping device positioned at the location of the heel 34 and configured to cooperate by friction with a circumferentially adjacent lateral face of the second of the two blades 3A so as to dampen dynamic stresses at the level of the heel 34 of the first of the two blades 3. Figures 8 to 10 show different positions of this rubbing element 50 in the housing 51 and with respect to the circumferentially adjacent lateral face of the blade.

[0055] In each of these positions, the rubbing element 50 is always at least partly in the housing 51, and partly outside of this housing 51.

[0056] In the embodiment presented, the rubbing element 50 is made from a material including ceramic or a ceramic matrix composite material.

[0057] As illustrated in figures 5 and 6, it presents a shape defined by a maximum dimension DI and a minimum dimension D2, with a ratio between the maximum dimension DI and the minimum dimension D2 less than or equal to 10, preferably less than or equal to 5.

[0058] As seen in figures 5 and 6, this element can have a rectangular prism shape with rounded edges.

[0059] More specifically, and also as can be seen in figures 5 and 6, this rubbing element 50 has a berlingot shape.

[0060] However, according to other embodiments, the friction element could have a shape among a cylindrical shape, an ellipsoidal shape, or can also be a friction element 50' having a berlingot shape as shown in figure 11.

[0061] Thus, its simple geometry and shape ratio allow for the implementation of a friction element with optimal robustness and compression performance.

[0062] A second embodiment of the invention is now presented in relation to figures 12 to 14. In this second embodiment, the heel 34' includes a first housing 51' cut into one of the upstream slots 340' and downstream slots 341' and opening at the level of the lateral face of the heel 34' so as to be positioned opposite the lateral face of the circumferentially adjacent blade 3A' when the blade 3' is mounted on the disc 22, and the dynamic damping device includes a friction element 50' mounted movably in the housing 51' between: a friction position in which the friction element 50' is at least partly in said housing 51', and is in contact with the lateral face of the circumferentially adjacent blade 3A' when the blade 3' is mounted on the disc 22, so that the friction element 50' cooperates by friction with the lateral face of the circumferentially adjacent blade 3A';a position set apart in which the rubbing element 50' is at least partly in the housing 51', and is at a distance from the lateral face of the circumferentially adjacent blade 3A' when the blade 3' is mounted on the disc 22.;

[0063] As illustrated, the dynamic damping device further includes a second housing 51' formed opening into the other of the upstream slit 340' and downstream slit 341' so that this second housing 510' opens at the level of said lateral face of the heel 34'.

[0064] Therefore, the dynamic damping device further includes a second friction element 50' mounted movably in the second housing 51' between: a friction position in which the second friction element 50' is at least partly in the second housing 51', and is in contact with the lateral face of the circumferentially adjacent blade 3A' when the blade 3' is mounted on the disk 22, so that the second friction element 50' cooperates by friction with the lateral face of the circumferentially adjacent blade 3A'; a distanced position in which the second friction element 50' is at least partly in the second housing 51', and is at a distance from the lateral face of the circumferentially adjacent blade 3A' when the blade 3' is mounted on the disk 22.

[0065] We now present, in relation to figures 15 and 16, a third embodiment of the invention.

[0066] In this third embodiment, the heel includes a first housing 51" cut into one of the upstream 340" and downstream slits and opening at the level of the lateral face of the heel so as to be positioned opposite the lateral face of the circumferentially adjacent blade 3A" when the blade 3" is mounted on the disc, and the dynamic damping device includes a friction element 50" movablely mounted in the housing 51" between: a friction position in which the friction element 50" is at least partly in said housing 51", and is in contact with the lateral face of the circumferentially adjacent blade 3A" when the blade 3" is mounted on the disc, so that the friction element 50" cooperates by friction with the lateral face of the circumferentially adjacent blade 3A";a position set apart in which the friction element 50" is at least partly in the housing 51", and is at a distance from the lateral face of the circumferentially adjacent blade 3A" when the blade 3" is mounted on the disc.;

Claims

DEMANDS

1. Blade (3, 3') configured to be mounted on a bladed wheel (20) of an aircraft turbomachine (1), said bladed wheel (20) comprising a disc (22) on which said blade (3, 3') is intended to be mounted such that several blades (3, 3') follow one another in a circumferential direction (23) of said bladed wheel (20) so as to form an annular row of blades (3, 3'), said blade (3, 3') comprising: a blade (33) having an aerodynamic profile; a foot (31) extending from a radially internal end of said blade (33) and configured to be mounted in a groove which opens into the outer periphery of said disc (22); a radially internal platform (32) separating said blade (33) from said foot (31); a heel (34, 34') extending to a radially external end of said blade (33), said heel (34, 34') comprising a radially external platform (40) from which extend radially outwards an upstream scrape (340,340') and a downstream blade (341, 341'), characterized in that said blade (3, 3') further comprises a dynamic damping device positioned at said heel (34, 34') and configured to cooperate by friction with a lateral face of a circumferentially adjacent blade (3A, 3A') so as to dampen dynamic stresses at said heel (34, 34'), and in that said heel (34, 34') comprises a housing (51, 51') cut into one of said upstream blades (340) and downstream blade (341) and opening at said lateral face of said heel (34, 34') so as to be positioned opposite said lateral face of said circumferentially adjacent blade (3A, 3A') when said blade (3, 3') is mounted on said disc (22), and in that said dynamic damping device comprises a friction element (50, 50') movably mounted in said housing (51, 51') enters: a friction position in which said friction element (50,50') is at least partially within said housing (51, 51'), and is in contact with said lateral face of said circumferentially adjacent blade (3A, 3A') when said blade (3, 3') is mounted on said disc (22), so that said friction element (50, 50') cooperates by friction with said lateral face of said circumferentially adjacent blade (3A, 3A'); a position set back in which said friction element (50, 50') is at least partially within said housing (51, 51'), and is at a distance from said lateral face of said circumferentially adjacent blade (3A, 3A') when said blade (3, 3') is mounted on said disc (22).

2. Blade according to claim 1, characterized in that said friction element (50, 50') is made from a material including ceramic or a ceramic matrix composite material.

3. Blade according to any one of the preceding claims, characterized in that said friction element (50, 50') has a shape defined by a maximum dimension (Dl) and a minimum dimension (D2), with a ratio between said maximum dimension (Dl) and said minimum dimension (D2) less than or equal to 10, preferably less than or equal to 5.

4. Blade according to any one of the preceding claims, characterized in that said friction element (50, 50') has a shape among a cylindrical shape, an ellipsoidal shape, a berlingot shape.

5. Blade according to any one of the preceding claims, characterized in that said housing (51, 51') is hollowed out by electro-erosion sinking.

6. Blade (3) according to the preceding claim, characterized in that said housing (51) is hollowed out in a direction inclined with respect to a direction tangential to said heel (34, 34').

7. Blade (3') according to any one of the preceding claims, characterized in that said dynamic damping device comprises a second housing (51') formed opening into the other of said upstream shim (340') and downstream shim (341') ​​such that said second housing (510') opens at the level of said lateral face of said heel (34'), and in that said dynamic damping device further comprises a second friction element (50') movably mounted in said second housing (51') between: a friction position in which said second friction element (50') is at least partially in said second housing (51'), and is in contact with said lateral face of said circumferentially adjacent blade (3A') when said blade (3') is mounted on said disc (22), such that said second friction element (50') cooperates by friction with said lateral face of said circumferentially adjacent blade (3A');a set-apart position in which said second rubbing element (50') is at least partly in said second housing (51'), and is at a distance from said lateral face of said circumferentially adjacent blade (3A') when said blade (3') is mounted on said disc (22).;

8. Bladed wheel (20) of an aircraft turbomachine (1), said bladed wheel (20) comprising a disc (22) and several blades (3, 3') according to any one of claims 1 to 7 mounted on said disc (22), said blades (3, 3') following one another in a circumferential direction (23) of said bladed wheel (20) so as to form an annular row of blades (3, 3'), and in that for any two given blades (3, 3A, 3', 3A'), a first of said two blades (3, 3') comprises a dynamic damping device positioned at said heel (34, 34') and configured to cooperate by friction with a circumferentially adjacent lateral face of said second of the two blades (3A, 3A') so as to dampen dynamic stresses at said heel (34, 34') of the said first of the said two paddles (3, 3').

9. Turbomachine (1) for aircraft comprising a bladed wheel according to claim 8.

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