Turbine rotor wheel for aircraft turbine

Abstract

A turbine rotor wheel (50) for an aircraft turbine, in particular, the turbine rotor wheel is a counter-rotating turbine wheel, the turbine rotor wheel comprising: a rotor disk (52), an annular shroud (54), the annular shroud extending around the disk, and blades (56), the blades being arranged between the disk and the shroud, characterized in that the root of each of the blades comprises two protrusions (66) for attachment to the disk, the protrusions being arranged respectively upstream and downstream of the wall (80) of the disk relative to the axis, the protrusion arranged upstream engaging in a first groove (70) of the disk and being configured to cooperate with the peripheral edge of the first groove by abutting against the peripheral edge (74) of the first groove, and the protrusion arranged downstream engaging in a second groove (72) of the disk and being configured to cooperate with the peripheral edge of the second groove by abutting against the peripheral edge (74) of the second groove.

Description

Technical Field

[0001] The invention relates to a turbine rotor wheel for an aircraft turbomachine, in particular to a counter-rotating turbine rotor wheel. Background Art

[0002] Generally, an aircraft turbine includes a fan, a low-pressure compressor, a high-pressure compressor, an annular combustion chamber, a high-pressure turbine and a low-pressure turbine from upstream to downstream in the flow direction of gas. The rotor of the low-pressure compressor is driven by the rotor of the low-pressure turbine, and the rotor of the high-pressure compressor is driven by the rotor of the high-pressure turbine.

[0003] From the perspective of engine performance and fuel consumption, maximizing the rotation speed of the low-pressure turbine is advantageous because it enables a higher efficiency of the turbine. However, increasing the rotation speed of the turbine means increasing the centrifugal force to which the turbine is subjected, making the design of the turbine very complicated.

[0004] One suggestion to improve the efficiency of the turbine without increasing the rotation speed of the turbine is to use a counter-rotating turbine. Therefore, the low-pressure turbine is replaced by a twin-rotor turbine, the first rotor of which is configured to rotate in a first rotation direction and is connected to a first turbine shaft, and the second rotor of which is configured to rotate in an opposite rotation direction and is connected to a second turbine shaft. The first rotor includes a turbine wheel portion inserted between the turbine wheel portions of the second rotor.

[0005] In a conventional architecture where the turbine directly drives the fan, the low-pressure turbine may have a takeoff speed of about 4,000 rpm, or in an architecture where the turbine drives the fan through a speed reduction device, the low-pressure turbine may have a takeoff speed of about 10,000 rpm. Replacing the low-pressure turbine with a counter-rotating turbine whose rotors rotate at takeoff speeds of about 3,000 rpm and 7,000 rpm, respectively, enables a relative speed of 10,000 (3000+7000) rpm, while having an absolute speed in the lower range of the above speed interval.

[0006] The counter-rotating turbine comprises a low-speed rotor driving the fan and a high-speed rotor meshing with a mechanical reduction device having an epicyclic gear train of planetary type, the input and output of which are counter-rotating (rotating ring gear, fixed planet carrier, rotating sun gear).

[0007] The speed reducer connects the high speed rotor and the low speed rotor, so that power can be transferred from the high speed rotor to the low speed rotor. By transferring most of the power from the turbine to the fan through the shaft without passing through the speed reducer, higher high speed turbine efficiency is achieved.

[0008] Due to the mechanical integration of this architecture, the architecture is complex. One problem is related to the transmission of torque between the low-speed rotor and the fan. This torque transmission is usually carried out through the last stage or last wheel of the low-speed rotor (i.e., the most downstream component) to directly transmit to the downstream end of the turbine shaft, the upstream end of which is connected to the fan.

[0009] One solution to this problem consists in implementing a torque transmission wheel in a component which is attached to the downstream end of the turbine shaft. Although torque transmission is ensured here, this solution is not satisfactory because, in operation, the wheel is subject to the operating temperatures which cause significant temperature gradients in the component, which may deform the wheel and cause it to lose its centering relative to its axis of rotation. These temperature gradients may also cause cracks and fissures to appear, and there is no provision to ensure that fragments of the component are retained after the component breaks. As a result, the fragments may leak into the turbine duct and cause significant damage to the engine. In particular, the present invention aims to provide a simple, effective and economical solution to at least some of the above problems.

[0010] For such a turbine wheel, it is not feasible to use conventional designs (for example those in documents EP-2 728 121-A2 or US-2011 / 110786-A1, which include blades held in place by dovetails or protrusions received in slots formed in the thickness of the disk) because these designs are too bulky in the axial direction. Summary of the invention

[0011] The present invention proposes a turbine rotor wheel for an aircraft turbomachine, in particular, the turbine rotor wheel is a counter-rotating turbine rotor wheel, the turbine rotor wheel comprises:

[0012] - a rotor disk extending around an axis X,

[0013] - an annular shroud extending around said axis X and said disk, and

[0014] a vane arranged between the disk and the shroud and comprising a root attached to the disk and a tip attached to the shroud,

[0015] It is characterized in that the root of each of the blades includes two protrusions for attachment to the disk, which are respectively arranged on the wall of the disk upstream and downstream relative to the axis, the protrusion arranged upstream is engaged in a first groove of the disk and is configured to cooperate with the peripheral edge of the first groove by abutting against the peripheral edge of the first groove, and the protrusion arranged downstream is engaged in a second groove of the disk and is configured to cooperate with the peripheral edge of the second groove by abutting against the peripheral edge of the second groove, the first groove and the second groove are located on both sides of the wall.

[0016] Thus, the attachment protrusion of each blade forms a convex part (or concave part), which engages in the concave part (or convex part) formed by the groove of the disk. The concave-convex engagement at the root of each blade ensures optimal torque transmission. In fact, the protrusion can cooperate with the peripheral edge of the groove by abutting against the peripheral edge of the groove, which makes it possible to have a large number of support and torque transmission surfaces. In addition, the construction of the wheel in multiple parts (rather than a single integral part) is advantageous because it limits the occurrence of large temperature gradients in a single part, thereby limiting the risk of deformation and cracking of the part. The assembly and manufacture of the wheel are relatively easy. Finally, the risk of the disk being off-center is reduced, and the concave-convex engagement can also make it possible to limit the risk of the blade entering the turbine duct due to breakage and loss.

[0017] The rotor wheel according to the invention may include one or more of the following features, taken alone or in combination with each other:

[0018] - said projections are substantially planar and parallel and extend in a plane substantially perpendicular to said axis X,

[0019] - said wall comprises a hole oriented parallel to said axis X and aligned with the hole of said boss, through which an attachment element passes; this attachment element makes it possible to ensure retention of the blade relative to the disk;

[0020] - at least some of the holes of the projection and of the wall have an elongated or oval shape and comprise a longer dimension oriented in a radial direction relative to said axis X; this shape makes it possible to ensure freedom of expansion of the component during operation;

[0021] - each of the protrusions comprises a first pair of circumferential stops and a second pair of circumferential stops, the first pair and the second pair being radially spaced from each other, each stop of each pair being suitable for bearing on said peripheral edge of the corresponding groove;

[0022] - the first pair of stops are at a distance from each other that is different from the distance between the second pair of stops;

[0023] The first groove and the second groove each comprise a first radially outer portion having a circumferential width or circumferential dimension D1 and a radially inner portion having a circumferential width or circumferential dimension D2, wherein D2 <D1;

[0024] - the buckets comprise blades connected to the root by platforms, which are arranged circumferentially next to each other around the disk;

[0025] - a heat shield having an annular shape is mounted and attached to the upstream or downstream face of the disk;

[0026] - the shroud is segmented and comprises shroud segments, each shroud segment being connected to the top of one of the blades, the shroud segments comprising segments of an annular flange for attachment to another rotor wheel;

[0027] - the shroud comprises a radially outer portion having a substantially cylindrical or frustoconical shape and being surrounded by the platform of the blade;

[0028] - the cover comprises a middle portion having a substantially C-shaped cross section defining an annular space in which the axial end of the attachment element is housed;

[0029] - The cover comprises a radially inner portion extending substantially perpendicularly to said axis X and being applied and attached against said disc.

[0030] The invention also relates to a turbomachine with a counter-rotating turbine for an aircraft, the turbomachine comprising a counter-rotating turbine having a first rotor and a second rotor, the first rotor being configured to rotate in a first rotational direction and being connected to a first turbine shaft, the second rotor being configured to rotate in an opposite rotational direction and being connected to a second turbine shaft, the first rotor comprising turbine wheel portions inserted between turbine wheel portions of the second rotor, characterised in that one of the wheel portions of the second rotor is as defined above and is connected to the second turbine shaft via a disk of the wheel portion.

[0031] Therefore, the wheel portion can ensure torque recovery and radial retention of the second turbine rotor.

[0032] Optionally but advantageously, the turbine wheels of the first rotor are connected to each other and to the first shaft internally of the duct and the turbine wheels of the second rotor are connected externally to the duct and to the second shaft via a disk of the wheel according to the invention.

[0033] Preferably, the turbine is of a type having a single shrouded fan which is driven in rotation by the first shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The invention will be better understood and other details, features and advantages thereof will become more apparent from the following description made by way of non-limiting example and with reference to the accompanying drawings, in which:

[0035] [ Figure 1 ] Figure 1 is a very schematic axial cross-sectional view of an aircraft turbomachine with counter-rotating turbines,

[0036] [ Figure 2 ] Figure 2 is a very schematic view of a counter-rotating turbine of an aircraft turbine,

[0037] [ Figure 3 ] Figure 3 is a schematic perspective view of a portion of a rotor wheel according to an embodiment of the present invention,

[0038] [ Figure 4 ] Figure 4 yes Figure 3 A larger scale view of a portion of

[0039] [ Figure 5 ] Figure 5 yes Figure 3 A schematic axial cross-sectional view of a rotor wheel in FIG.

[0040] [ Figure 6 ] Figure 6 yes Figure 3 A schematic perspective view of the radially inner end of a blade of a rotor wheel section,

[0041] [ Figure 7 ] Figure 7 yes Figure 3 A partial schematic perspective view of a disk of a rotor wheel portion in FIG.

[0042] [ Figure 8 ] Figure 8 yes Figure 7 Detailed view of the disk;

[0043] [ Fig. 9 ] Fig. 9 is similar to Figure 8 and showing the radially inner ends of the blades attached to the disk, and

[0044] [ Fig.10 ] Fig.10 yes Figure 3 Schematic front view of the radially inner end of the rotor wheel and the disk in FIG. DETAILED DESCRIPTION

[0045] Figure 1A very schematic illustration of a turbomachine 10 with counter-rotating turbines for an aircraft is shown.

[0046] The turbomachine 10 includes, from upstream to downstream in the flow direction of gas, a fan 12 , a low-pressure compressor 14 , a high-pressure compressor 16 , an annular combustion chamber 18 , a high-pressure turbine 20 , and a counter-rotating turbine 22 .

[0047] Reference numeral 24 denotes an intermediate casing located between the compressors 14 and 16, reference numeral 26 denotes a turbine casing (a turbine casing of the TVF type, TVF being the abbreviation of the turbine vane frame, a turbine casing of the turbine vane frame type indicating a turbine casing equipped with arms forming straightening blades) located between the turbines 20 and 22. Finally, reference numeral 28 denotes an exhaust casing (an exhaust casing of the TRF type, TRF being the abbreviation of the turbine rear frame, an exhaust casing of the turbine rear frame type indicating the last turbine casing). These casings form the structure of the turbine: they support the bearings that guide the shaft in rotation and are coupled to the suspension of the turbine.

[0048] The rotor of the high-pressure turbine 20 drives the rotor of the high-pressure compressor 16 in rotation via a high-pressure shaft 30, which is centrally positioned and guided in rotation by bearings, such as an upstream ball bearing 32 and a downstream roller bearing 34. The bearing 32 is mounted between the upstream end of the shaft 30 and the intermediate housing 24, and the bearing 34 is mounted between the downstream end of the shaft 30 and the turbine housing 26.

[0049] The counter-rotating turbine 22 includes a first rotor 22a having a wheel portion 22aa, the first rotor being configured to rotate in a first rotational direction and connected to a first turbine shaft 36, and a second rotor having a wheel portion 22ba, the second rotor being configured to rotate in an opposite rotational direction and connected to a second turbine shaft 38, the wheel portions 22ba of the second rotor being interleaved between the wheel portions 22aa of the rotor 22a.

[0050] Each turbine wheel section includes an annular row of buckets, each of the buckets including an aerodynamic profile including a soffit and a spur that join to form leading and trailing edges for gas in the turbine duct.

[0051] The first shaft 36 drives in rotation the rotors of the fan 12 and the low-pressure compressor 14. Furthermore, this first shaft 36 meshes with a ring gear 40 of a mechanical reduction device 42 having an epicyclic gear train of the planetary type.

[0052] The second shaft 38 meshes with a sun gear 44 or a planetary arrangement of the reduction gear 42 .

[0053] The reduction gear 42 also includes planetary gears that mesh with the sun gear 44 and the ring gear 40 , respectively, and are carried by a planet carrier 46 attached to the exhaust housing 28 .

[0054] Each of the housings 26 and 28 generally includes a central hub and an outer annular portion surrounding the hub and connected to the hub by a series of arms generally radial to the longitudinal axis of the turbine. The central hub of the housing 28 extends around at least a portion of the reduction gear 42 .

[0055] Figure 2 The downstream end of the turbine is shown on a larger scale, in particular the counter-rotating turbine 22 of the turbine. Figure 2 Elements in the embodiment which have been described previously are indicated by the same reference numerals. In this embodiment, the planet carrier 46 is attached to the turbine housing 26 .

[0056] exist Figure 2 As can be seen, rotor 22a, referred to as the high speed rotor, is connected to shaft 38, which meshes with sun gear 44 or planetary gear of reduction gear 42. Rotor 22b, referred to as the low speed rotor, is connected to shaft 36, which meshes with ring gear 40 of reduction gear 42 and drives the fan.

[0057] The connection of the rotor 22 b to the shaft 36 is made through the last stage or last wheel of the rotor and must advantageously be designed to transmit the rotational torque (arrow F1 ) to the shaft 36 while limiting the constraints related to thermal gradients during operation and ensuring radial retention of the second turbine rotor.

[0058] The turbine wheels 22aa of the first rotor 22a are connected to each other and inside the duct to the first shaft 38. According to the invention, the turbine wheel 22ba of the second rotor 22b is externally connected to the duct and the second shaft 36 via the disk of the wheel 22ba1.

[0059] The present invention proposes a solution to this problem, and embodiments of the present invention are Figure 3 and shown below.

[0060] The solution is that the rotor wheel 50 is configured so as to be able to transmit the torque ( F1 ) while having an optimal service life.

[0061] The rotor wheel 50 generally comprises three parts, namely

[0062] a rotor disk 52 extending about an axis X which is the longitudinal axis of the turbomachine,

[0063] an annular shroud 54 extending around the axis X and the disk 52 , and

[0064] Vanes 56 , which are arranged between the disk 52 and the shroud 54 .

[0065] The buckets 56 extend generally radially between the disk 52 and the shroud 54 and each includes an aerodynamically shaped blade 58 including a soffit 58a and a soffit 58b connected by a leading edge 58c and a trailing edge 58d.

[0066] The radially outer end of the blade 58 or of the vane 56 is called the tip and is rigidly connected here to the shroud 54. The shroud 54 is segmented and therefore comprises a plurality of segments arranged circumferentially around the axis X next to one another.

[0067] The radially inner end of bucket 56 includes a root 60 connected to blade 58 by a platform 62. Figure 3 As seen in , the platform 62 of the bucket 56 is intended to be located above or outside the disk 52 and to be arranged between two adjacent bucket platforms 62 .

[0068] The root 60, platform 62, blade 58 and even the shroud section 54 may be integrally formed. Figure 3 In FIG. 5 , only one of the blades 58 is shown in its entirety. The other blades of the wheel section are shown partially, with only the platform 62 and the root 60 of the blade being visible.

[0069] Like the shroud segments 54 , the platforms 62 of the buckets 56 are arranged circumferentially around the disk 52 and the axis X next to each other.

[0070] Each platform 62 comprises an upstream edge 62a, a downstream edge 62b, and two side edges 62c extending between the edges 62a, 62b. The edge 62c of each platform 62 is located at a short distance from the edge 62c facing the adjacent platform.

[0071] The same is true for the shroud segments 54. Each shroud segment 54 includes an upstream edge 54a, a downstream edge 54b, and two side edges 54c extending between the edges 54a, 54b. The edge 54c of each platform 54 is located at a short distance from the edge 54c facing the adjacent shroud segment. In addition, the edge 54a of each segment includes an attachment flange segment 64, and the flange segments 64 of all shroud segments 54 form an annular attachment flange, in particular, the annular attachment flange is attached to an adjacent shroud (not shown) that is integral with another wheel portion of the turbine rotor 22b. The flange or each flange segment 64 includes an axial hole for passing an attachment element such as a screw nut.

[0072] The root 60 of each bucket 56 comprises two lugs 66 for engagement in grooves 68 of the disk 52 and for attachment thereto.

[0073] exist Figure 7 and Figure 8 The disc 52 is shown separately in FIG. The disc has a generally annular shape, i.e. the center of the disc is hollow. The connection device of the disc 52 to the shaft 36 for the transmission of the torque (F1) is not shown.

[0074] The root 60 of the blade 56 is attached to the periphery of the disk 52 , which comprises an upstream face 52a and a downstream face 52b . The first grooves 70 are present on the upstream face 52a and are evenly distributed around the axis X. The second grooves 72 are present on the upstream face 52b and are evenly distributed around the axis X.

[0075] The number of grooves 70 is equal to the number of grooves 72 , and each of the grooves 72 is positioned in axial alignment with one of the grooves 70 .

[0076] In the example shown, the shape of the grooves is identical. Alternatively, however, the shape of the grooves may be different to form an indicator and prevent improper assembly of the blade (direction of the leading edge towards downstream instead of upstream).

[0077] The grooves 70 and 72 are Figure 8 , and comprises a generally T-shaped shape. Each groove comprises a first radially outer portion (relative to the axis X) having a circumferential width or circumferential dimension D1 and a radially inner portion having a circumferential width or circumferential dimension D2. D2 <D1。

[0078] Each groove 70, 72 comprises a peripheral edge 74 which is discontinuous in the example shown in that each groove opens radially outwardly to an outer peripheral edge 76 of the disc. Each of the portions of the grooves 70, 72 comprises circumferentially facing abutting side surfaces 78.

[0079] The bottom of the grooves 70, 72 is formed by the wall 80 of the disk. Figure 7 This makes it possible to show that the grooves are located on both sides of these walls 80 .

[0080] The walls 80 each comprise an axial hole 82. Preferably, the hole 82 has an elliptical shape or an elongated shape, wherein the axis of extension is oriented radially with respect to the axis. This means that each hole 82 has a longest dimension oriented radially.

[0081] As in Figure 4 , Figure 5 as well as Figure 6, an attachment element 84, such as a bolt, passes through the hole 82 and a hole 85 in the boss 66 of the blade 56. Preferably, each hole 85 has an elliptical shape similar to the elliptical shape of the hole 82. The shank 84a of the bolt extends through the holes 82, 85 and includes: an end connected to a head 84b, which is supported on one of the bosses 66 of the blade; and an opposite end, which receives a nut 84c, which is supported on the other of the bosses 66 of the blade (see Figure 5 ).

[0082] The attachment element 84 passes through the oblong holes 82 , 85 and the wall 80 of the projection 66 , which allow for differential thermal expansion between the components, particularly in the radial direction, during operation.

[0083] The root 60 of the blade 56, in particular the radially inner end of the blade, is Figure 6 Shown separately in.

[0084] The projections 66 are substantially planar and parallel and extend in a plane substantially perpendicular to the axis X. The projections are spaced from one another by a distance corresponding to the thickness of the wall 80 intended to be inserted between the projections 66 .

[0085] Each protrusion 66 is designed to engage in a groove 70, 72 by a male-female fit and therefore comprises a shape that is almost complementary to the shape of the groove (see Fig. 9 ).

[0086] Each protrusion 66 comprises a generally figure-8 shape and comprises two parts, an outer part 66a and an inner part 66b. The outer part 66a is intended to engage in the outer part of the groove 70 and comprises a hole 85 of the protrusion. The part 66a comprises a first pair of circumferential stops 86.

[0087] The inner portion 66 b is intended to engage in the inner portion of the groove 70 and does not comprise a hole. This portion 66 b comprises a second pair of circumferential stops 88 .

[0088] The first and second pairs of stops 86, 88 are radially spaced from each other. The stops 86 are adapted to cooperate by bearing against the surfaces 78 of the grooves 70, 72 in the circumferential direction and the stops 88 are adapted to cooperate by bearing against the surfaces 78 of the grooves in the circumferential direction.

[0089] The stops 86 are at a distance from one another which is different from the distance between the stops 88 and, in particular in the example shown, is greater than the distance between the stops 88 .

[0090] exist Figure 5In the example shown in FIG. 5 , a heat shield 90 having an annular shape is mounted and attached to the upstream face 52a of the disk 52. The shield 90 covers the face 52a to protect it from heat radiation from, for example, a turbine duct.

[0091] In the example shown, the cover 90 is formed in one piece and comprises three parts, namely a radially outer part 90a, a middle part 90b and a radially inner part 90c.

[0092] The portion 90a is substantially cylindrical or frustoconical in shape and is surrounded by the platform 62 of the blade 56. The intermediate portion 90b has a C-shaped cross section defining an annular space 92 in which the axial end of the bolt, for example the head of the bolt or a nut, is housed. Finally, the portion 90c extends substantially perpendicularly to the axis X and is applied and attached against the disk 52.

[0093] Fig.10 The complete wheel portion is shown, but the entire shroud 54 and buckets 56 are not shown.

[0094] The wheel parts can be mounted in the following manner. The root of each blade is mounted on the periphery of the disk on one of the walls 80. To this end, each blade is positioned radially on the outside of the disk so that the protrusion 66 of the blade is located in a plane perpendicular to the axis X and thus parallel to the wall 80 and so that the wall is aligned with the inter-protrusion space. The blade is then moved radially from the outside to the inside so that the protrusion engages in a form-fitting manner in the grooves 70, 72 of the disk. The protrusion thus engages in the grooves starting from the open radial inner end of these grooves.

[0095] When all the blades are installed in this way, the platforms 62 of these blades and the shroud segments 54 of the blades are wedged together in the circumferential direction. The blades 56 are automatically positioned by cooperating with the adjacent blades. This adjustment enables the assembly to withstand centrifugal forces. For example, Fig.10 , the centrifugal force F2 applied to the two radially opposite blades 56' of the disk is at least partially borne by the circumferential support (arrow F3) of the stops 86, 88 of the blade roots on the surfaces facing the corresponding grooves of the stops. In addition, the circumferential distribution of the stops makes it possible to ensure positioning in the center, because as in Fig.10The vertical displacement shown in will be blocked by the support (F3), thereby ensuring that the positioning in the center is maintained. Specifically, each protrusion has: a stop part in the stop part 86, which cooperates with one of the surfaces 78 of the grooves 70, 72 by abutting against the surface; and a stop part in the stop part 88, which is located on the opposite side of the protrusion and cooperates with one of the corresponding surfaces 78 of the grooves 70, 72 by abutting against the surface. As shown in the figures, this is particularly true for two radially opposite blades 56" located at 90° to the blade 56'.

[0096] As described above, in particular, the rotor wheel according to the invention enables recovery of the rotational torque ( F1 ), radial expansion freedom so as not to overstress the wheel, and central arrangement of the wheel.

Claims

1. A turbine rotor wheel (50) for an aircraft turbomachine, the turbine rotor wheel comprising: - a rotor disk (52) extending around an axis X, an annular shroud (54) extending around the axis X and the rotor disk, and a blade (56) arranged between the rotor disk and the annular shroud and comprising a root (60) attached to the rotor disk and a tip attached to the annular shroud, The invention is characterized in that the root of each of the blades comprises two protrusions (66) for attachment to the rotor disk, the protrusions being arranged respectively upstream and downstream of the wall (80) of the rotor disk relative to the axis, the protrusion arranged upstream being engaged in a first groove (70) of the upstream face (52a) of the rotor disk and being configured to cooperate with the peripheral edge (74) of the first groove by abutting against the peripheral edge (74) of the first groove, and the protrusion arranged downstream being engaged in a second groove (72) of the downstream face (52b) of the rotor disk and being configured to cooperate with the peripheral edge (74) of the first groove by abutting against the peripheral edge (74) of the first groove. Abutting against the peripheral edge (74) of the second groove to cooperate with the peripheral edge of the second groove, the first groove and the second groove are located on both sides of the wall, the wall (80) includes a hole (82), the hole is oriented parallel to the axis X and is aligned with the hole (85) of the protrusion (66), the attachment element (84) passes through the hole of the protrusion and the hole of the wall, at least some of the holes (85) of the protrusion (66) and the holes (82) of the wall (80) have an elongated shape or an elliptical shape and include a longer dimension oriented in a radial direction relative to the axis X.

2. The turbine rotor wheel (50) according to claim 1, wherein: The projections (66) are substantially planar and parallel and extend in a plane substantially perpendicular to the axis X.

3. The turbine rotor wheel (50) according to claim 1 or 2, wherein: Each of the protrusions (66) includes a first pair of circumferential stops (86) and a second pair of circumferential stops (88), wherein the first pair of circumferential stops and the second pair of circumferential stops are radially spaced apart from each other, and each circumferential stop in each pair of circumferential stops is adapted to bear against the peripheral edge (74) of the corresponding groove in the first groove (70) and the second groove (72).

4. The turbine rotor wheel (50) according to claim 1 or 2, wherein: The first groove (70) and the second groove (72) each include a first radially outer portion and a radially inner portion, wherein the first radially outer portion has a circumferential width or circumferential dimension D1 and the radially inner portion has a circumferential width or circumferential dimension D2, wherein D2 <D1。 5. The turbine rotor wheel (50) according to claim 1 or 2, wherein: The bucket (56) includes blades (58) connected to the root (60) by platforms (62) which are circumferentially arranged next to each other around the rotor disk (52).

6. The turbine rotor wheel (50) according to claim 1 or 2, wherein: A heat shield (90) having an annular shape is installed and attached to the upstream surface (52a) or the downstream surface (52b) of the rotor disk (52).

7. The turbine rotor wheel (50) according to claim 1 or 2, wherein: The annular shroud (54) is segmented and includes shroud segments, each shroud segment being connected to the top of one of the blades (56), the shroud segments including segments (64) of annular flanges for attachment to another turbine rotor wheel.

8. The turbine rotor wheel (50) according to claim 1, wherein: The turbine rotor wheel portion is a counter-rotating turbine rotor wheel portion.

9. A turbomachine (10) with a counter-rotating turbine for an aircraft, the turbomachine comprising a counter-rotating turbine (22), the counter-rotating turbine having a first rotor (22a) and a second rotor (22b), the first rotor being configured to rotate in a first rotational direction and being connected to a first turbine shaft (36), the second rotor being configured to rotate in an opposite rotational direction and being connected to a second turbine shaft (38), the first rotor comprising a turbine rotor wheel portion inserted between turbine rotor wheel portions of the second rotor, characterized in that One of the turbine rotor wheel parts of the second rotor is as defined in any one of claims 1 to 8 and is connected to the second turbine shaft via a rotor disk of the one turbine rotor wheel part.

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