BE1030191A1 - Assembly for an aircraft turbomachine, and associated turbomachine and aircraft - Google Patents

Abstract

The present invention relates to an assembly (17) for an aircraft turbine engine compressor in which a vane magnet (58) is located on a magnetized rotor vane (56) and a first shroud (34) comprises a shroud magnet (70 ). When the distance (72) between the vane magnet (58) and the ferrule magnet (70) is less than a threshold, the vane magnet (58) pushes the ferrule magnet (70) so as to move the first shroud (34) from a radially inner position (64) to a radially outer position (66).

Description

Assembly for an aircraft turbomachine, and associated turbomachine and aircraft

Technical area

The present invention relates to an assembly for an aircraft turbomachine. The present invention also relates to a turbomachine and an aircraft comprising at least one such turbomachine.

Prior art

[0002] EP 3 006 679 describes an axial turbomachine, in particular an outer casing of the axial turbomachine. The outer casing comprises a circular wall comprising an internal annular groove, an outer sealing shroud arranged in the groove and intended to provide sealing between the outer casing and an annular row of rotor blades of the turbomachine, and connecting elements connecting the outer shroud to the circular wall. The connecting elements are piezoelectric actuators configured to move and/or deform the outer shroud in order to modify the clearance between the outer shroud and the rotor blades. In this way, the position of the outer shroud is controlled by moving it quickly, which makes it possible to effectively control the play between the shroud and the blades.

[0003] In such a turbomachine it is necessary to provide numerous complex parts, for example the piezoelectric elements.

These many parts pose difficulties of integration, reliability (in real time and over the life of the turbomachine), and require the creation of effective control routines. In addition, such a turbomachine requires the management of services such as the supply of electricity to the piezoelectric elements. When the piezoelectric elements are for example, according to a variant, replaced by mechanical arms, the turbomachine requires the supply of oil, or air depending on the type of actuation chosen.

Summary of the invention

[0004] One of the aims of the present invention is to provide a turbomachine which allows better management of the clearances between the rotor blades and the circular wall, and which is particularly simple.

[0005] To this end, the invention proposes an assembly for an aircraft turbomachine compressor, comprising: - an outer circular wall having an axial direction, - a row of rotor blades arranged inside the outer circular wall and comprising a plurality of rotor blades, each rotor blade having an outer end edge, - a blade magnet located on a magnetized rotor blade belonging to the plurality of rotor blades, - a first shroud located between the circular wall external and the row of rotor blades, and movable between a radially internal position and a radially external position, - an elastic element connecting the first ferrule to the external circular wall, the first ferrule comprising a ferrule magnet, the assembly being configured so that the blade magnet, when its distance from the shroud magnet is less than a threshold, pushes the shroud magnet so as to cause the first shroud to pass from its radially inner position to its radially outer position.

[0006] When the distance between the vane magnet and the shroud magnet is less than the threshold, the first shroud is pushed outwards, into its radially outer position by the magnetic interaction between the dawn, and the ferrule magnet. Thus, the play between the rotor blades and the first shroud (that is to say their radial separation) is passively controlled, instead of being actively controlled as described in the state of the art. Consequently, the assembly according to the invention avoids the disadvantages of active game management.

[0007] Furthermore, in the invention, when the distance between the vane magnet and the ferrule magnet is greater than the threshold, the first ferrule is pushed towards the axis, in its radially internal position, by the elastic element. This allows adequate play whatever the engine speed, and in particular at low speed when the blade head is far from the shroud.

[0008] According to embodiments, the assembly according to the invention may comprise one or more of the following characteristics: the blade magnet extends over a length less than 40% of the length of the outer end edge of the rotor blade, preferably less than 10% of the length of the outer end edge of the rotor blade; e the blade magnet extends over substantially the entire outer end edge of the rotor blade; e the first ferrule is entirely in a magnetic material which forms the ferrule magnet; the magnetized rotor vane includes at least two spatially axially offset vane magnets, and the first shroud includes at least two spatially axially staggered shroud magnets, the vane magnets (58) and the shroud magnets aligning radially ; e the magnetized rotor blade has a lower surface and an upper surface opposite the lower surface, the blade magnet being arranged on the lower surface next to the outer end edge or the upper surface next to the outer end edge, vane magnet preferably having a surface less than 1.5 mm? ; the row of rotor blades comprises two magnetized rotor blades each spaced apart by 180°, preferably four magnetized rotor blades each spaced apart by 90°; e the row of rotor blades comprises at least one group of magnetized rotor blades made up of magnetized rotor blades adjacent to each other;

e the outer circular wall comprises an abutment, and the first ferrule comprises a niche configured to cooperate with the abutment so as to prevent the first ferrule from moving, radially inwards, beyond its radially internal position; e the first ferrule comprises a support and a layer of abradable material facing the rotor blades, the layer of abradable material having a lower hardness than that of the rotor blades, the ferrule magnet being at least partially embedded in the layer of abradable material ; * the outer circular wall comprises at least one groove, and for each groove, the assembly comprises a second ferrule configured to be arranged and immobilized in the groove, the elastic element connecting the first ferrule to the second ferrule; e the second ferrule is made of a non-magnetic material; e at least one of the blade magnet or the ferrule magnet is a permanent magnet; e the blade magnet is attached to the magnetized rotor blade by gluing or welding; e the first shell is segmented along the circumferential direction of the assembly; e the first ferrule is in one piece and comprises a continuous annular surface in the circumferential direction of the assembly;

[0009] The invention also relates to a turbomachine comprising an assembly according to the invention.

[0010] The invention further relates to an aircraft comprising at least one such turbomachine.

Brief description of figures

Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended figures, among which:

- Figure 1 shows an axial turbomachine according to the invention. - Figure 2 shows a turbomachine compressor according to the invention. - Figure 3 is a circumferential sectional view illustrating a rotor blade and a first shroud according to the invention. 5 - Figure 4 is a sectional view of a first ferrule comprising a support and a layer of abradable material. - Figure 5 is a sectional view of the abutment of the outer circular wall and the niche of the first shell. - Figure 6 illustrates an embodiment having a second ferrule. -Figure 7 is a perspective view of a magnetized rotor blade according to the invention.

Embodiments of the Invention

The present invention is described with specific embodiments and references to figures, but the invention is not limited by them. The drawings or figures described are only schematic and are not limiting. In addition, the functions described may be performed by other structures than those described in this document.

[0013] In the context of this document, the terms “first” and “second” only serve to differentiate the various elements and do not imply an order between these elements.

In the figures, identical or similar elements may bear the same references.

[0015] Figure 1 schematically shows an axial turbomachine. In this specific case, it is a turbofan engine. The turbojet engine 2 comprises a first compression level, called low-pressure compressor 4, a second compression level, called high-pressure compressor 6, a combustion chamber 8 and one or more levels of turbines 10. In operation, the mechanical power of the turbine 10 transmitted via the central shaft to the rotor 12 sets in motion the two compressors 4 and 6. The latter comprise several rows of rotor blades associated with rows of stator blades. The rotation of the rotor 12 around its axis of rotation 14 thus makes it possible to generate an air flow and to gradually compress the latter until it enters the combustion chamber 8.

An inlet fan commonly referred to as a fan or blower 16 is coupled to the rotor 12 and generates an airflow which is divided into a primary flow 18 crossing the various above-mentioned levels of the turbomachine, and a secondary flow 20 crossing an annular duct (partially shown) along the machine to then join the primary flow at the turbine outlet. The secondary flow can be accelerated so as to generate a reaction. The primary 18 and secondary 20 flows are annular flows, they are channeled through the casing of the turbine engine. For this purpose, the casing has cylindrical walls or shells which can be internal and external.

Figure 2 is a sectional view of a compressor of an axial turbomachine such as that of Figure 1. The compressor may be a low-pressure compressor 4. There can be observed a flow separation nozzle 22 primary 18 and the secondary flow 20. The rotor 12 comprises at least one row of rotor blades 24, in this case three.

The low pressure compressor 4 comprises at least one rectifier, in this case four, which each contain a row of stator vanes 26. The rectifiers are associated with the fan 16 or with a row of rotor vanes 24 to straighten the airflow, so as to convert the speed of the flow into pressure.

[0019] Subsequently, the description focuses on an assembly 27 comprising a row of rotor blades 24. The assembly 27 can be located in the low pressure compressor 4.

The assembly 27 includes an outer circular wall 30. The assembly 27 includes a row of rotor blades 24 disposed inside the outer circular wall 30. The assembly 27 includes a first shroud 34 located between the outer circular wall 30 and the row of rotor blades 24.

The assembly 27 also includes an elastic element 36 connecting the first ferrule 34 to the outer circular wall 30.

According to one embodiment illustrated in Figure 6, the assembly 27 further comprises at least a second ferrule 40.

The outer circular wall 30 extends in the axial direction. The outer circular wall 30 can be made of a composite material, for example with an organic resin and carbon fibers, and/or optionally a fiberglass ply. The composite material improves the strength-to-weight ratio. The presence of glass fibers has the effect of creating an insulating layer. The outer circular wall 30 may have a generally constant thickness in order to preserve its lightness, its compactness, and to simplify the production of a corresponding fiber preform.

According to an embodiment shown in Figure 5 which will be explained below, the outer circular wall 30 includes a stop 48.

According to one embodiment shown in Figure 6 which will be explained below, the outer circular wall 30 comprises at least one groove 50. Each groove 50 is adapted to receive a second ferrule 40 so that the second ferrule 40 is arranged and immobilized in the groove 50.

The row of rotor vanes 24 comprises a plurality of rotor vanes 52. As seen in Figure 2, each rotor vane 52 extends substantially in the axial direction. Each rotor blade 52 has an outer end edge 54.

The row of rotor blades 24 comprises, among the rotor blades 52, at least one magnetized rotor blade 56. The magnetized rotor blade 56 comprises at least one blade magnet 58. The blade magnet 58 is for example fixed to the magnetized rotor blade 56 by gluing or welding.

The welding is for example carried out by shrinking or by oxyacetylene welding.

According to a first embodiment shown in Figure 6, the blade magnet 58 extends over substantially the entire outer end edge 54 of the rotor blade 52.

According to a second embodiment, the blade magnet 58 extends over a length less than 40% of the length of the outer end edge 54 of the rotor blade 52, preferably less than 10% the length of the outer end edge 54 of the rotor blade 52. The length of the outer end edge 54 is to be measured along said edge, and not in a straight line.

[0029] Preferably, blade magnets 58 are distributed along the outer end edge 54 of the magnetized rotor blade 56. For example, according to a particular example of the second embodiment represented on the

Figure 3, the vane magnets 58 extend along the outer end edge 54 of the magnetized rotor vane 56.

According to another particular example of the second embodiment, shown in Figure 7, the magnetized rotor blade 56 has a lower surface 60 and an upper surface (not visible in Figure 7) opposite the lower surface 60.

The vane magnet 58 is preferably arranged on the lower surface 60 next to the outer end edge 54. However, at least one vane magnet 58 can be on the upper surface next to the outer end edge 54 , in addition to or instead of the lower surface 60, while remaining within the scope of the invention.

The leading edge, the trailing edge or the chord between them can comprise one or more vane magnet(s) 58 while remaining within the scope of the invention.

Advantageously, the blade magnet 58 has a surface area of less than 1.5 mm2, more advantageously substantially equal to 1 mm2.

In such a case, the blade magnet 58 is for example of the Neodymium type of the order of 8 milligrams. By “beside” is meant a distance between the blade magnet 58 and the outer end edge 54 of less than 30% of the radial height of the magnetized rotor blade 56. This embodiment presents the technical advantage that the vane magnet 58 does not come into contact with the first shroud 34. Thus the vane magnet 58 is more durable.

According to the embodiment shown in Figure 7, the magnetized rotor blade 56 comprises three blade magnets 58 arranged substantially in the radial direction of the assembly 17.

According to one embodiment, the row of rotor blades 24 comprises two magnetized rotor blades 56 each spaced apart by 180°.

Advantageously, the row of rotor blades 24 comprises four magnetized rotor blades 56 each spaced apart by 90°. The configuration where the row of rotor blades 24 comprises several magnetized rotor blades 56 has two advantages. The first advantage is the redundancy of the blade magnets 58 on a row of rotor blades 24 to ensure a minimum distance between the rotor blades 52 and the first shroud 34. The second advantage is to avoid the unbalance effect on the row of rotor blades 52 due to the presence of a single blade magnet 58 thereon.

According to another embodiment, the row of rotor blades 24 comprises at least one group of magnetized rotor blades consisting of magnetized rotor blades 56 adjacent to each other.

The first shroud 34 is movable between a radially inner position 64 (shown in Figure 6) and a radially outer position 66 (shown in Figure 3).

According to one embodiment, the first ferrule 34 is segmented along the circumferential direction of the assembly 17.

According to another embodiment, the first ferrule 34 is in one piece, for example in half-shell. The first shroud 34 then comprises a continuous annular surface along the circumferential direction of the assembly 17.

The first shell 34 is made of metal or a composite material.

The first ferrule 34 comprises at least one ferrule magnet 70.

When the distance 72 between the vane magnet 58 and the shroud magnet 70 is less than a threshold, the vane magnet 58 pushes the shroud magnet 70 so as to cause the first shroud 34 to pass from its radially internal position 64 to its radially external position 66. The distance 72 between the outer end edge 54 of the magnetized rotor blades 56 and the first ferrule 34 when the first ferrule 34 occupies its radially internal position 64 is strictly smaller than the distance 72 between the outer end edge 54 of the magnetized rotor blades 56 when the first shroud 34 occupies its radially outer position 66.

The threshold is preferably between 0.01 mm and 0.9 mm.

The pole of the vane magnet 58 opposite the first shroud 34 and the pole of the shroud magnet 70 opposite the rotor blade 52 are of the same polarity.

According to one embodiment, the first ferrule 34 is entirely in a magnetic material which forms the ferrule magnet 70.

According to another embodiment shown in Figure 3, the first shroud 34 comprises at least two shroud magnets 70 axially offset, and the magnetized rotor blade 56 comprises at least two vane magnets 58 axially offset. The vane magnets 58 and the ferrule magnets 70 align radially. This configuration allows better repulsion of the first shroud 70 by the magnetized rotor blade 56 when their distance 72 decreases below the threshold.

According to one embodiment, at least one of the blade magnet 58 or of the ferrule magnet 70 is a permanent magnet.

According to one embodiment shown in Figure 5, the first ferrule 34 comprises a niche 76. The niche 76 is configured to cooperate with the abutment 48 of the outer circular wall 30 so as to prevent the first ferrule 34 from move, radially inward, beyond its radially inner position 64.

According to one embodiment shown in Figure 4, the first shroud 34 comprises a support 78 and a layer of abradable material 80 opposite the rotor blades 52. The support 78 is for example made of metal or a composite material . The layer of abradable material 80 has a lower hardness than the rotor blades 52. Thus, when the rotor blade 52 comes into contact with the layer of abradable material 80, the rotor blade 52 rubs a part of the layer of abradable material 80 without coming into contact with support 78.

Advantageously, the ferrule magnet 70 is at least partially embedded in the layer of abradable material 80.

The elastic element 36 is for example a spring.

The elastic element 36 is arranged to put the first ferrule 34 in its radially internal position 64 when the rotor is stationary.

The elastic element 36, when the distance 72 between the vane magnet 58 and the ferrule magnet 70 is greater than the threshold, returns the first ferrule 36 to its radially outer position 66.

[0051] …— Advantageously, the assembly 27 comprises at least one damper (not shown in the Figures) in parallel with the elastic element 36. The damper is configured to damp the movement of the first ferrule 34 relative to the wall outer circular 30. In particular, the damper avoids jumps of the first ferrule 34 towards its radially outer position 66 during the successive passages of the magnetized rotor blade(s) 56.

As mentioned above, the second ferrule 40 is positioned and immobilized in the groove 50. As shown in Figure 6, the second ferrule 40 is connected to the first ferrule 34 by the elastic element 36.

According to one embodiment, the second ferrule 40 is made of a non-magnetic material.

According to the embodiment where the first ferrule 34 is segmented along the circumferential direction of the assembly 17, the second ferrule 40 is preferably also segmented along the circumferential direction of the assembly 17.

According to the embodiment where the first ferrule 34 is in one piece, the second ferrule 40 is preferably also in one piece. The second shell 40 then comprises a continuous annular surface along the circumferential direction of the assembly 17. This configuration facilitates maintenance and assembly/disassembly of the assembly 17.

In other words, the invention relates to an assembly 17 for an aircraft turbomachine compressor in which a blade magnet 58 is located on a magnetized rotor blade 56 and a first shroud 34 comprises a shroud 70. When the distance 72 between the vane magnet 58 and the shroud magnet 70 is less than a threshold, the vane magnet 58 pushes the shroud magnet 70 so as to pass the first shroud 34 from a radially inner position 64 to a radially outer position 66.

The present invention has been described in relation to specific embodiments, which are purely illustrative and should not be construed as limiting. In general, the present invention is not limited to the examples illustrated and/or described above.

The use of the verbs "understand", "include", "compose", or any other variant, as well as their conjugations, can in no way exclude the presence of elements other than those mentioned. The use of the indefinite article "UN", "une", or of the definite article "le", "la" or "l'", to introduce an element does not exclude the presence of a plurality of these elements. The reference numbers in the claims do not limit their scope.

Claims (17)

Claims 1. Assembly (17) for an aircraft turbomachine compressor, comprising: - an outer circular wall (30) having an axial direction, - a row of rotor blades (24) arranged inside the outer circular wall ( 30) and comprising a plurality of rotor vanes (52), each rotor vane (52) having an outer end edge (54), - a vane magnet (58) located on a magnetized rotor vane (56) belonging to the plurality of rotor blades (52), - a first shroud (34) located between the outer circular wall (30) and the row of rotor blades (24), and movable between a radially internal position (64) and a radially outer position (66), - an elastic element (36) connecting the first shroud (34) to the outer circular wall (30), the first shroud (34) comprising a shroud magnet (70), the assembly (17 ) being configured so that the blade magnet (58), when its distance (72) from the ferrule magnet (70) is less than a threshold, repels the ferrule magnet (70) so as to pass the first ferrule (34) from its radially inner position (64) to its radially outer position (66). 2. An assembly (17) according to claim 1, wherein the blade magnet (58) extends over a length less than 40% of the length of the outer end edge (54) of the rotor blade ( 52), preferably less than 10% of the length of the outer end edge (54) of the rotor blade (52). 3. An assembly (17) according to claim 1, wherein the vane magnet (58) extends over substantially the entire outer end edge (54) of the rotor vane (52). 4. An assembly (17) according to claim 1, wherein the first ferrule (34) is entirely of a magnetized material which forms the ferrule magnet (70). 5. An assembly (17) according to claim 1 or 2, wherein the magnetized rotor blade (56) comprises at least two vane magnets (58) spatially offset axially, and the first shroud (34) comprises at least two (70) spatially offset axially, the vane magnets (58) and the ferrule magnets (70) aligning radially. 6. Assembly (17) according to any one of the preceding claims, in which the magnetized rotor blade (56) has a lower surface (60) and an upper surface opposite the lower surface (60), the blade magnet ( 58) being arranged on the lower surface (60) next to the outer end edge (54) or the upper surface next to the outer end edge (54). 7. An assembly (17) according to any preceding claim, wherein the row of rotor vanes (24) comprises two magnetized rotor vanes (56) each spaced 180° apart, preferably four magnetized rotor vanes (56) spaced each 90°. 8. An assembly (17) according to any preceding claim, wherein the row of rotor vanes (24) comprises at least one group of magnetized rotor vanes consisting of magnetized rotor vanes (56) adjacent to each other. . 9. Assembly (17) according to any one of the preceding claims, in which the outer circular wall (30) comprises an abutment (48), and the first shroud (34) comprises a recess (76) configured to cooperate with the abutment. (48) so as to prevent the first shroud (34) from moving radially inward beyond its radially inner position (64). 10. Assembly (17) according to one of the preceding claims, in which the first shroud (34) comprises a support (78) and a layer of abradable material (80) facing the rotor blades (52), the layer of abradable material (80) having a lower hardness than that of the rotor blades (52), ferrule magnet (70) being at least partially embedded in the layer of abradable material (80). 11. Assembly (17) according to any one of the preceding claims, in which the outer circular wall (30) comprises at least one groove (50), and for each groove (50), the assembly (17) comprises a second ferrule (40) configured to be disposed and immobilized in the groove (50), the elastic element (36) connecting the first ferrule (34) to the second ferrule (40). 12. Assembly (17) according to the preceding claim, wherein the second ferrule (40) is made of a non-magnetic material. 13. An assembly (17) according to any preceding claim, wherein at least one of the vane magnet (58) or the ferrule magnet (70) is a permanent magnet. 14. Assembly (17) according to any one of the preceding claims, in which the blade magnet (58) is fixed to the magnetized rotor blade (56) by gluing or welding. 15. Assembly (17) according to any one of the preceding claims, in which the first ferrule (34) is in one piece and comprises a continuous annular surface in the circumferential direction of the assembly (17). 16. Turbomachine, comprising an assembly (17) according to any one of the preceding claims. 17. Aircraft comprising at least one turbomachine according to the preceding claim.