CMC bladed turbine wheel and N-tuple structural mast

Abstract

Turbomachine (1) distributor (11) comprising bladed sectors (12.1-12.16) in which at least one bladed sector (12.1-12.16) comprises: - an inner platform (20) and an outer platform (50); - two blades (15.1, 15.2) each extending radially from the inner platform (20) to the outer platform (50); - two masts (30, 40) extending from the inner platform (20) to the outer platform (14); - each mast (30, 40) having a radially internal end (31, 41) rigidly attached to the inner platform (20); - each mast (30, 40) having a radially external end (33, 43) fixed to the outer platform (14) by a mechanical linkage interface (51, 52), Figure 4

Description

Title of the invention: CMC blade turbine wheel and N-tuple structural mast technical field

[0001] The present invention relates to the field of aircraft turbomachinery, and more specifically to turbine wheels equipping such machines.

[0002] It relates more specifically to the reduction of leaks on high-pressure compressor distributor stage wheels.

[0003] The invention applies to all turbomachine designs, for example turbojets with a fan driven directly by a low-pressure body, driven indirectly by a reducer, single-body, twin-body, single-flow and twin-flow turbojets. PREVIOUS STATE OF THE ART

[0004] In a turbomachine, here a turbojet identified 1 in [Fig.1], air is admitted into an inlet sleeve 2 to pass through a fan comprising a series of rotating blades 3 before splitting into a central primary flow which circulates in a so-called primary airflow circulation channel and a secondary flow surrounding the primary flow.

[0005] The primary flow is compressed by compressor stages 4 and 5 before reaching a combustion chamber 6, after which it expands as it passes through turbines 7, before being discharged, generating thrust. The secondary flow, on the other hand, is propelled directly by the blower to generate the main thrust.

[0006] The compressor stages comprise distributors regularly spaced around a shaft mounted to rotate about an axis AX in a nacelle 8 surrounding the assembly and between which are placed distributor stages 9 in the form of fixed bladed wheels 10.

[0007] It is known, in particular from documents FR3080145 and FR3061928, to produce a distributor stage of a turbojet turbine in the form of a wheel comprising bladed sectors arranged to jointly form an inner and an outer concentric shell with blades extending radially from the inner shell to the outer shell.

[0008] Conventionally, each blade is made in the form of a fairing of ceramic matrix composite material that defines an internal housing for the blade. Ceramic matrix composite (CMC) materials withstand temperatures ranging from 600°C to 1400°C. Due to their superior resistance to high temperatures, CMCs require less cooling. This cooling is traditionally provided by By reducing the compressor's intake, which impacts turbomachine efficiency, CMC materials improve engine efficiency, thereby reducing fuel consumption. Furthermore, the use of ceramic matrix composite materials helps optimize turbomachine performance, notably by reducing the overall mass of the turbomachine, which further contributes to lower fuel consumption and thus a significant reduction in pollutant emissions.

[0009] A bladed sector then comprises an inner ferrule sector and an outer ferrule sector connected by a structural mast extending through the inner housing of a blade. The distributor is obtained by assembling and joining as many wheel sectors as the distributor has blades. The gaps between two adjacent wheel sectors are sources of primary airflow leakage from the duct, which impacts the thermodynamic efficiency of the turbojet.

[0010] The invention aims to reduce leaks of the primary airflow out of the duct and thus increase the thermodynamic efficiency of the turbojet. Description of the invention

[0011] To this end, a turbomachine distributor is provided comprising bladed sectors arranged circumferentially around an axis to form a ring having a concentric inner and outer ferrule and blades extending radially from the inner to the outer ferrule. A bladed sector according to the invention comprises an inner platform and an outer platform, each forming a sector of the inner and outer ferrules respectively, two blades extending radially from the inner platform to the outer platform, and two masts extending within an internal housing of one of the two blades from the inner platform to the outer platform. Each mast has a radially internal end rigidly attached to the inner platform. Each mast also has a radially external end fixed to the outer platform by a mechanical linkage interface.Preferably, each mechanical link interface includes a pin for securing a mast to the external platform.

[0012] The turbomachine distributor thus obtained has a reduced number of interfaces between internal shell sectors compared to the prior art, and therefore a reduced level of primary airflow leakage from the intake duct. Having a single platform supporting two masts also allows for perfect control of the clearances and cross-sections between two adjacent blades mounted on the same platform, which is essential for a high-pressure turbine distributor.

[0013] Advantageously, the two mechanical linking interfaces each have a receiving bore for a pin, each bore being formed in a mast.

[0014] Advantageously, at least one blade has a radially external end which has a base covering an internal face of the external platform of the bladed sector of which this blade is a part and / or at least one blade has a radially internal end which has a base covering an external face of the internal platform of the bladed sector of which this blade is a part.

[0015] The positioning of the internal platform relative to the external platform is achieved with precision when at least one mechanical linking interface includes a cylindrical housing formed in a hollow in the external platform and receiving a radially external mast end.

[0016] Advantageously still, each pin is received in a bore extending in a transverse direction and which is made in a radially external end of the mast.

[0017] Preferably, the masts project radially outward from an inner face of the external platform and / or the mechanical linkage interface includes a pin that extends transversely to one of the two masts.

[0018] Advantageously, the internal platform and the two masts form a single unit.

[0019] The thermodynamic efficiency of the turbomachine is further improved by reducing the cooling air intake when at least one blade is made of ceramic matrix composite material.

[0020] The invention also applies to a turbomachine comprising a distributor as defined above and to an aircraft comprising such a turbomachine. Brief description of the drawings

[0021] [Fig.1] is a schematic cross-sectional representation of a turbomachine;

[0022] [Fig.2] is a schematic plan view representation of a distributor according to the invention;

[0023] [Fig.3] is a schematic perspective representation of a sector of the distributor of the [Fig.2];

[0024] [Fig.4] is a schematic perspective representation of an exploded view of the sector of the [Fig.3].

[0025] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0026] As seen in [Fig.1], a distributor stage 10 of the turbomachine 1 is fitted to an aircraft (not shown) and includes a low-pressure distributor 11.

[0027] For the purposes of this application, the terms "internal" and "external" are used with reference to the position or orientation relative to the axis of rotation AX of the turbomachine 1.

[0028] The distributor 11 comprises bladed sectors 12.1 to 12.16 arranged circumferentially 11 is arranged around the axis AX to form a ring having an inner ferrule 13 and an outer ferrule 14 concentric in a manner known to those skilled in the art. The distributor 11 also includes blades 15.1 to 15.32 which extend radially from the inner ferrule 13 to the outer ferrule 14.

[0029] Sectors 12.1 to 12.16 are all identical and only one sector 12.1 will now be described.

[0030] As can be seen in Figures 3 and 4, the sector 12.1 comprises an internal platform 20 forming an internal ferrule sector 13 and an external platform 50 forming an external ferrule sector 14. The internal platforms 20 comprise means for connecting them to form the internal ferrule 13 and the external platforms 50 comprise means for connecting them to form the external ferrule 14. A first blade 15.1 and a second blade 15.2, respectively defined by a first fairing 60 and a second fairing 70 made of ceramic matrix composite materials, each extend radially from the internal platform 20 to the external platform 50.

[0031] As more particularly visible in [Fig.4], the internal platform 20 comprises a base 21 from which a first structural mast 30 and a second structural mast 40 project radially.

[0032] The first mast 30 has a first radially internal end 31 welded to the base 21. The second radially external end 32 of the mast 30 includes a first portion 33 in the shape of a straight cylinder which includes a first bore 34 extending diametrically through the first portion 33. The mast 30 also includes bearing surfaces 35 distributed over its outer surface 36.

[0033] The second mast 40 is identical to the first and has a third end 41 radially internally welded to the base 21 and a fourth end 42 radially externally which includes a second portion 43 in the shape of a straight cylinder. The second portion 43 includes a second bore 44 extending diametrically through the second portion 43. The mast 40 also includes bearing surfaces 45 distributed over its outer surface 46. The internal platform 20 is thus a single piece.

[0034] For the purposes of this application, an assembly is said to be monobloc when it consists of elements linked in an indissoluble manner to each other, for example by full-mass machining processes, welding, shrink-fitting or gluing.

[0035] The external platform 50 includes a first blind cylindrical housing 51 and a second blind cylindrical housing 52 shaped to respectively accommodate the end portion 33 of the mast 30 and the end portion 43 of the mast 40.

[0036] The first housing 51 comprises two diametrically opposed first holes 53.1 and 53.2. Similarly, the second housing 52 comprises two diametrically opposed second holes 54.1 and 54.2.

[0037] The fairing 60 of the first blade 15.1 defines a first internal housing 61 of a first blade 62 and includes a fifth end 63 radially internal and a sixth end 64 radially external. Both the fifth end 63 and the sixth end 64 have a quadrilateral circumference.

[0038] The second blade 15.2 is identical to the first blade 15.1, and the fairing 70 defines a second internal housing 71 for a second blade 72 and includes a seventh end 73 radially internal and an eighth end 74 radially external. The seventh end 73 and the eighth end 74 both have a quadrilateral circumference.

[0039] The first bladed sector 12.1 is formed by engaging the first fairing 60 on the internal platform 20 so that the first mast 30 extends into the internal housing 61, inside the blade 62. The second fairing 70 is engaged on the internal platform 20 so that the second mast 40 extends into the internal housing 71, inside the blade 72. The bearing surfaces 35 and 45 respectively come into contact with the inner faces 65 and 75 of the fairings 60 and 70 and ensure that the fairings 60 and 70 are held in position relative to the masts 30 and 40.

[0040] The external platform 50 is then positioned so that the housings 51 and 52 respectively accommodate the portions 33 and 43 of the masts 30 and 40. A first connecting pin 55 is engaged in the first holes 53.1 and 53.2 so as to extend into the first bore 34. A second connecting pin 56 is engaged in the second holes 54.1 and 54.2 so as to extend into the second bore 44. Thus, the respective portions 33 and 43 of the masts 30 and 40 project radially outward from an inner face 57 of the external platform 50.

[0041] As seen in [Fig.3], the inner end 63 of the first fairing 60 and the inner end 73 of the second fairing 70 jointly have an inner cover base which covers an outer face 22 of the inner platform 20. The outer face 22 and the inner faces of the inner ends 63 and 73 include homologous profiles for locking the fairings 60 and 70 in position relative to the inner platform 20.

[0042] Similarly, the outer end 64 of the first fairing 60 and the outer end 74 of the second fairing 70 jointly have an outer cover base which covers the inner face 57 of the outer platform 50. The inner face 57 and the outer faces of the outer ends 64 and 74 include homologous profiles for locking the fairings 60 and 70 in position relative to the outer platform 50.

[0043] Thus, the adjacent edges of the internal extremities 63 and 73 extend vertically along a continuous portion of the internal platform sector 20, which prevents any leakage of the primary airflow from the vein at this level. Similarly, the edges adjacent external extremities 64 and 74 extend vertically over a continuous portion of the external platform 50, which prevents any leakage of the primary airflow out of the vein at this level.

[0044] The bladed sector 12.1 thus formed is assembled with the other identical sectors 12.2 to 12.16 to form the distributor 11 of the turbomachine 1. This gives a distributor stage in which the level of leakage of the primary air flow out of the stream is reduced.

[0045] Obviously, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0046] In particular, - although here the bladed sector comprises two masts whose internal radial ends are rigidly attached to the internal platform, the invention also applies to a bladed sector comprising a different number of masts whose internal radial ends are rigidly attached to the internal platform, such as three or more; - although here the internal radial ends are welded to the internal platform, the invention also applies to other methods for rigidly joining the masts and the internal platform such as shrink fitting, casting, machining from solid or additive manufacturing; - although here the external platform includes two blind cylindrical housings, the invention also applies to other types of mechanical linkage interface such as non-removable interfaces (fretted, welded, press-fitted), through or differently shaped housings, or a linkage interface including a radially projecting shaft intended to engage in a housing of a structural mast; - although here the external platform comprises two blind cylindrical housings, the invention also applies to other configurations of the winged sector such as for example a single external platform for a plurality of internal platforms or a staggered arrangement of internal and external platforms; - although here the outer ends of the fairings that define the blades jointly cover the entire inner face of the outer platform, the invention also applies to a blade having a radially outer end covering at least partially the inner face of the outer platform of which this blade is a part; - although here the inner ends of the fairings that define the blades jointly cover the entire outer face of the inner platform, the invention also applies to a blade having a radially internal end covering at least partially the external face of the external platform of which this blade is a part.

Claims

Demands

1. Turbomachine (1) distributor (11) comprising bladed sectors (12.1-12.16) arranged circumferentially around an axis (AX) to form a ring having a concentric inner ferrule (13) and outer ferrule (14), blades (15.1-15.32) extending radially from the inner ferrule (13) to the outer ferrule (14), in which at least one bladed sector (12.1-12.16) comprises: - an inner platform (20) and an outer platform (50) each forming respectively a sector of the inner ferrule (13) and the outer ferrule (14); - two blades (15.1, 15.2) each extending radially from the inner platform (20) to the outer platform (50); - two masts (30, 40) each extending into an internal housing of one of the two blades (15.1, 15.2) from the inner platform (20) to the outer platform (14); - each mast (30, 40) having a radially inner end (31, 41) rigidly attached to the inner platform (20); - each mast (30, 40) having a portion (33, 43) of a radially outer end (32, 42) attached to the outer platform (14) by a mechanical linkage interface (51, 52), preferably each mechanical linkage interface (51, 52) comprising a pin for securing a mast to the outer platform (50), in which each mechanical linkage interface (51, 52) comprises a pin (55, 56) which extends transversely to one of the two masts (30, 40).

2. Distributor (11) according to claim 1, wherein the two mechanical linkage interfaces (51, 52) each have a receiving bore (34, 44) for a pin (55, 56), each bore being formed in a mast.

3. Distributor (11) according to claim 2, comprising at least one blade (15.1-15.2) which has a radially external end (64, 74) having a base covering an internal face (57) of the external platform (50) of the bladed sector (12.1) and / or at least one blade (15.1, 15.2) which has a radially internal end (63, 73) having a base covering an external face (22) of the internal platform (20) of the bladed sector (12.1).

4. Distributor (11) according to claim 2 or 3, wherein each pin (55, 56) is received in a bore (34, 44) extending along a transverse direction and which is carried out in the portion (32, 42) of the radially external end (33, 43) of the mast (30, 40).

5. Distributor (11) according to any one of claims 1 to 4, wherein at least one mechanical linkage interface (51, 52) comprises a cylindrical housing (51, 52) formed in a hollow in the external platform (50) and receiving a radially external end (33, 43) of mast (30, 40).

6. Distributor (11) according to any one of claims 1 to 5, wherein the two masts (30, 40) radially project outwards from an inner face (57) of the outer platform (50).

7. Distributor (11) according to any one of claims 1 to 6, wherein the internal platform (50) and the two masts (30, 40) form a single unit.

8. Distributor (11) according to claim 3, comprising at least one blade (15.1, 15.2) made of ceramic matrix composite material.

9. Turbomachine (1) comprising a distributor (11) according to any one of the preceding claims.

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