ROTOR DISC WITH AXIAL RETENTION OF THE BLADES, ASSEMBLY OF A DISC AND A RING, AND TURBOMACHINE

Abstract

A rotor disc for a turbomachine, the disc extending circumferentially about an axis and including a plurality of cavities configured to receive blade roots, each cavity including a downstream radial wall configured to axially block the blade root in the cavity, each downstream radial wall including a channel of ventilation of the cavity, including an inlet orifice which opens into the cavity and an outlet orifice which opens onto a downstream surface of the disc. An assembly for a turbomachine including such a disc and an upstream retention ring and a turbomachine including such an assembly.

Claims

1. A rotor disc for a turbomachine, the disc extending circumferentially about an axis and comprising a plurality of cavities configured to receive blade roots, each cavity comprising a downstream radial wall configured to axially block the blade root in the cavity, each downstream radial wall comprising a channel of ventilation of the cavity, comprising an inlet orifice which opens into the cavity and an outlet orifice which opens onto a downstream surface of the disc.

2. The disc according to claim 1, wherein the outlet orifice opens onto a downstream surface of the downstream radial wall.

3. The disc according to claim 1, wherein the ventilation channel links at least two inlet orifices and one outlet orifice.

4. The disc according to claim 1, wherein the ventilation channel links all of the inlet orifices.

5. The disc according to claim 1, wherein the inlet orifices have an inlet diameter and the outlet orifices have an outlet diameter, the number of inlet orifices being greater than or equal to the number of outlet orifices and the inlet diameter being smaller than or equal to the outlet diameter.

6. The disc according to claim 1, wherein at least one among the inlet orifices is axially aligned with at least one among the outlet orifices.

7. The disc according to claim 1, wherein at least one among the inlet orifices is circumferentially and/or radially offset relative to at least one among the outlet orifices.

8. The disc according to claim 1, wherein the downstream radial wall has a thickness greater than or equal to 0.5 mm and less than or equal to 10 mm.

9. The disc according to claim 1, wherein the inlet orifices and/or the outlet orifices have a diameter greater than or equal to 0.5 mm and less than or equal to 10 mm.

10. An assembly for a turbomachine comprising a disc according to claim 1 and an upstream retention ring.

11. A turbomachine comprising an assembly according to claim 10.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Other characteristics and advantages of the object of the present disclosure will emerge from the following description of embodiments, given by way of non-limiting examples, with reference to the appended figures, in which:

[0048] FIG. 1 is a schematic longitudinal sectional view of a turbojet engine;

[0049] FIG. 2 is an enlarged view of a portion of FIG. 1;

[0050] FIG. 3 is a partial perspective view of a turbine disc according to a first embodiment;

[0051] FIG. 4 is a partial perspective view of the disc of FIG. 3;

[0052] FIG. 5 is a partial perspective view of a turbine disc according to a second embodiment;

[0053] FIG. 6 is a sectional view along the plane VI-VI of FIG. 5;

[0054] FIG. 7 is a view similar to the view of FIG. 5 with a partial section showing a ventilation channel.

[0055] In all the figures, the elements in common are identified by identical numeric references.

DETAILED DESCRIPTION

[0056] FIG. 1 represents in cross-section along a vertical plane passing through its main axis A, a turbofan engine 10 which is an example of a turbomachine. The turbofan engine 10 includes, from upstream to downstream along the circulation of the air stream F, a fan 12, a low-pressure compressor 14, a high-pressure compressor 16, a combustion chamber 18, a high-pressure turbine 20 and a low-pressure turbine 22.

[0057] The terms “upstream” and “downstream” are defined in relation to the direction of circulation of the air in the turbomachine, in this case, according to the circulation of the air stream F in the turbojet engine 10.

[0058] The turbojet engine 10 includes a fan casing 24 extended rearward, that is to say downstream, by an intermediate casing 26, including an outer shroud 28 as well as a parallel inner shroud 30 disposed, along a radial direction R, internally relative to the outer shroud 28. The radial direction R is perpendicular to the main axis A.

[0059] The terms “outer” and “inner” are defined in relation to the radial direction R so that the inner portion of an element is, along the radial direction, closer to the main axis A than the outer portion of the same element.

[0060] The intermediate casing 26 further includes structural arms 32 distributed circumferentially and extending radially between the inner shroud 30 up to the outer shroud 28. For example, the structural arms 32 are bolted to the outer shroud 28 and on the inner shroud 30. The structural arms 32 allow stiffening the structure of the intermediate casing 26.

[0061] The main axis A is the axis of rotation of the turbojet engine 10 and of the low-pressure turbine 22. This main axis A is therefore parallel to the axial direction.

[0062] The low-pressure turbine 22 comprises a plurality of blade impellers which form the rotor of the low-pressure turbine 22.

[0063] FIG. 2 represents a first and a second stage of the low-pressure turbine 22. The first stage includes a first blade impeller 34 formed of a first disc 36 on the periphery of which blades 38 are assembled. Likewise, the second stage includes a second blade impeller 40 formed of a second disc 42 on the periphery of which blades 38 are assembled. The first and second blade impellers 34, 40 are separated from each other by a distributor 44.

[0064] The first and second discs 36, 42 of the rotor each include at least a linking shroud 46.

[0065] In the embodiment of FIG. 2, the first disc 36 includes a linking shroud 46, in this case a downstream linking shroud 46 and the second disc 42 includes two linking shrouds 46, an upstream linking shroud 46 and a downstream linking shroud 46. The first and second discs 36, 42 are assembled with each other by means of a plurality of bolts 48 disposed along a circumferential direction C in orifices carried by the downstream linking shroud 46 of the first disc 36 and by the upstream linking shroud 46 of the second disc 42. The bolts 48 also allow assembling a movable ring 50 to the first blade impeller 34 and to the second blade impeller 40.

[0066] In FIG. 2, the movable ring 50 includes an assembly web 52 extending along the radial direction R.

[0067] The movable ring 50 carries sealing wipers 54 which sealingly cooperate with a ring of abradable material 56 carried by the distributor 44.

[0068] As represented in FIG. 2, the blade 38 is assembled on the first disc 36 by insertion of a blade root 58 in a cavity 60 for receiving a blade root.

[0069] As can be seen in FIG. 3, the cavity 60 is delimited along the circumferential direction C by teeth 62 forming portions of the first disc 36 delimiting the cavities 60 along the circumferential direction C. Each cavity 60 includes a downstream radial wall 64. The downstream radial wall 64 is formed integrally with the teeth 62 of the disc 36 and therefore the disc 36 and allows axially blocking the blade root 58 in the cavity 60. Particularly, the axial blocking is achieved by abutting a downstream face 58A of the blade root 58 against an upstream face 64A of the downstream radial wall 64.

[0070] In the embodiment of FIGS. 2 to 4, each downstream radial wall 64 including a channel of ventilation 66 of the cavity. The channel of ventilation 66 of the cavity 60 includes an inlet orifice 68 and an outlet orifice 70. The ventilation channel 66 opens, through the inlet orifice 68, onto the upstream face 64A of the downstream radial wall 64 and, through the outlet orifice 70, on a downstream face 34A of the disc 34. In the embodiment of FIGS. 2 to 4, the outlet orifice 70 opens onto the downstream face of the radial wall 64, that is to say each downstream radial wall 64 includes an inlet orifice 68 and an outlet orifice 70.

[0071] In one embodiment, not represented, the outlet orifice 70 could open onto a portion of the downstream face 34A of the disc 34 which is not the downstream face of the downstream radial wall 64.

[0072] In the embodiment of FIGS. 2 to 4, the inlet orifice 68 of each ventilation channel 66 is aligned with the outlet orifice 70 along a direction parallel to the main axis A, that is to say a direction parallel to the axis of rotation of the first disc 36. In addition, the inlet orifice 68 and the outlet orifice 70 are circular in shape, the inlet orifice 68 has an inlet diameter D68 and the outlet orifice 70 has an outlet diameter D70, the inlet diameter D68 of the inlet orifice 68 being equal to the outlet diameter D70 of the outlet orifice 70. The ventilation channel 66 therefore has the shape of a right cylinder with a circular base whose axis is parallel to the main axis A of the turbojet engine 10.

[0073] The blades 38 of the first blade impeller 34 include a hook for holding 72 an upstream retention ring 74 for the axial blocking of the blades 38 in the cavities 60.

[0074] In the embodiment of FIG. 2, only the first disc 36 includes cavities each including a downstream radial wall. It will be noted that the blade 38 of the second blade impeller 40 includes hooks for holding 72 an upstream and downstream retention ring. It is understood that the second disc 42 could also include cavities each including a downstream radial wall to allow the axial locking of the blade roots. The same applies to the other stages of the low-pressure turbine 22. The blades 38 of these discs could then only include a single groove 72 for receiving an upstream retention ring. It will be noted that in the embodiment of FIG. 2, the movable ring 50 includes a portion acting as an upstream retention ring 74 for the blades 38 of the second blade impeller 40.

[0075] For example, the first disc 36 may be produced by additive manufacture, in particular by a powder bed-based additive manufacturing method.

[0076] In the following, the elements common to the different embodiments are identified by the same numeric references.

[0077] FIGS. 5 to 7 represent a second embodiment. In the embodiment of FIGS. 5 to 7, the ventilation channel 66 of the first disc 36 extends along the circumferential direction C and goes around the first disc 36.

[0078] In the embodiment of FIGS. 5 to 7, the ventilation channel 66 links all the inlet orifices 68 together and links at least two inlet orifices 68 to an outlet orifice 70.

[0079] For example, in the embodiment of FIGS. 5 to 7, each downstream radial wall 64 does not include an outlet orifice 70, each downstream radial wall 64 including an inlet orifice 68, that is to say an inlet orifice 68 opens onto the upstream face 64A of each downstream radial wall 64. For example, the downstream radial wall 64 of a cavity 60 out of two includes an outlet orifice 70. This example is not limiting. Thus, the downstream radial wall 64 of a cavity 60 out of three, or even more, may include an outlet orifice 70.

[0080] In the embodiment of FIGS. 5 to 7, in a first cavity 60 whose downstream radial wall 64 includes an inlet orifice 68 and an outlet orifice 70, the inlet orifice 68 is aligned with the outlet orifice of the ventilation channel 66 of the first cavity 60. In a second cavity 60, adjacent to the first cavity 60, the downstream radial wall 64 includes an inlet orifice 68 communicating with the outlet orifice 70 of the first cavity 60 thanks to the ventilation channel 66 and the inlet orifice 68 of the second cavity 60 is not aligned with the outlet orifice 70, the inlet orifice 68 is offset along the circumferential direction C relative to the outlet orifice 70 of the ventilation channel 66 of the second cavity 60. It is understood that the ventilation channel 66 of the second cavity 60 links the inlet orifice 68 of the downstream radial wall 64 of the second cavity 60 to the outlet orifice 70 of the downstream radial wall 64 of the first cavity 60.

[0081] In the embodiment of FIGS. 5 to 7, the inlet diameter D68 of the inlet orifices 68 is smaller than the outlet diameter D70 of the outlet orifices 70.

[0082] Although the present disclosure has been described with reference to a specific exemplary embodiment, it is obvious that various modifications and changes may be made to these examples without departing from the general scope of the invention as defined by the claims. For example, the inlet orifice might not be aligned along a direction parallel to the main axis A with the outlet orifice.

[0083] Furthermore, individual characteristics of the different embodiments mentioned may be combined in additional embodiments. Consequently, the description and the drawings should be considered in an illustrative rather than a restrictive sense.