Gasket for turbomachine

Abstract

The present disclosure relates to an annular seal (20) configured to cooperate in a contactless sealing manner with a surface which is arranged radially opposite the annular seal (20) and which is rotatable relative to the annular seal (20), the annular seal (20) comprising a radially inner annular wall (21) and a radially outer annular wall (22) connected together by at least one elastically deformable member, the annular seal (20) comprising at least one row of hollow patterns (211, 212) opening onto a radially inner surface (S1) of the radially inner annular wall (21), the radially inner annular wall (21) comprising at least one visual wear indicator (24) of the patterns (211, 212),said at least one visual wear indicator (24) extending over an upstream axial end surface (S2) and over the radially inner surface (S1) of the radially inner annular wall (21). Abstract figure: Figure 5,

Description

Title of the invention: Gasket for turbomachine Technical field

[0001] The present disclosure relates to a seal, and in particular to a seal for an aeronautical turbomachine. Prior art

[0002] [Fig.l] schematically represents an aeronautical turbomachine 1 with a double flow of longitudinal axis XL. The turbomachine 1 generally comprises, from upstream AM to downstream AV according to the direction of flow of the gases within the turbomachine 1, a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6, a low-pressure turbine 7 and an exhaust system downstream of the turbomachine 1. The gas flow, in particular air, entering upstream of the turbomachine 1 first circulates through the fan 2 and then divides, on the one hand, into an annular circulation vein called the primary vein 8, and on the other hand, into an annular circulation vein called the secondary vein 9 surrounding the primary vein 8. The low-pressure compressor 3, the high-pressure compressor 4, the combustion chamber 5, the high-pressure turbine 6 and the low-pressure turbine pressure 7 are arranged in the primary vein 8.

[0003] The turbomachine is all the more efficient when it operates at high temperature. In particular, a surrounding area of ​​the combustion chamber is subjected to particularly high temperature conditions which can induce thermal expansion. The high-pressure turbine 6 conventionally comprises a turbine rotor disk arranged at the outlet of the combustion chamber 5. The turbine rotor disk comprises an annular shroud on which are mounted rotor blades driven in rotation by a flow of gas ejected by the combustion chamber 5. This flow of gas at high temperatures subjects the annular shroud and the rotor blades to significant thermal stresses.

[0004] In order to limit the impact of these thermal constraints on the service life of the various components of the turbomachine, and in particular the rotor blades, it is known to implement ventilation circuits. These ventilation circuits are conventionally supplied by air taken from the bottom of the combustion chamber.

[0005] Generally speaking, the design of the ventilation circuits of an aeronautical turbomachine is delicate and represents a potential loss of performance. In order to ensure that the ventilation circuits are not supplied with more cooling air than necessary, and therefore do not unduly harm the performance of the turbomachine, labyrinth seals are generally installed at the air sampling locations.

[0006] Such seals make it possible to ensure controlled air passage at the locations where they are arranged. It is conventional to use labyrinth seals comprising wipers cooperating opposite each other with an abradable element having a cellular structure such as honeycomb.

[0007] However, this type of seal has the major disadvantage of frictional wear of the wipers and the abradable element. This leads to an increase in the clearance and therefore air leakage through the seal. Such an increase in air leakage causes an increase in the air temperature and a decrease in the efficiency of the turbomachine.

[0008] In this context, there is therefore a need for a seal which wears less during its lifetime compared to conventional labyrinth seals and it is also sought to estimate the wear of this seal, particularly in the context of scheduled inspections of the turbomachine. Summary

[0009] An annular seal is provided, the annular seal being axial and being configured to cooperate in a contactless sealing manner with a surface which is arranged radially opposite the annular seal and which is rotatable about the axis relative to the annular seal. The annular seal comprises a radially inner annular wall and a radially outer annular wall connected together by at least one elastically deformable member. The annular seal comprises at least one row of hollow patterns opening onto a radially inner surface of the radially inner annular wall. The radially inner annular wall comprises at least one visual indicator of wear of the patterns, said at least one visual indicator of wear extending over an upstream axial end surface and over the radially inner surface of the radially inner annular wall.Said at least one visual wear indicator is configured to evolve geometrically according to the wear of the patterns.

[0010] In particular, such a non-contact seal operates with a small and controlled annular clearance between the latter and said surface when the latter is rotating. This type of seal is also commonly referred to as a hydrostatic or hydrodynamic seal depending on the configuration of the integrated patterns. Furthermore, this type of seal aims to achieve an adaptation of the clearance during operation. The use of this type of seal then offers the advantage of controlling the leakage flow at the seal, and thus makes it possible to improve the performance of the turbomachine.

[0011] Such an annular sealing joint may in particular be configured to ensure a predefined clearance, also referred to as a “target” clearance. It is then possible for the clearance to vary slightly around the predefined clearance value under conditions of use of the seal. When the seal is in its equilibrium position, the predefined clearance ensures that the flow of air passing through the seal is the desired airflow. However, if the clearance increases or decreases, the seal will be returned to the predefined clearance by elastic deformation in the radial direction of the seal.

[0012] More precisely, if the clearance of the seal becomes smaller than the predefined clearance, the radial pressure under the radially internal surface of the seal induces a displacement of the latter so as to increase the clearance, whereas if the clearance of the seal becomes larger than the predefined clearance, the seal exerts a force greater than the pressure exerted radially under the radially internal surface of the seal so as to bring said surface back to its equilibrium position, i.e. to the predefined clearance.

[0013] This aerodynamic balance makes it possible to prevent at any time the radially internal surface of the annular sealing joint from coming into contact with the radially opposite surface. This avoids the problem of wear which can be encountered with conventional labyrinth seals.

[0014] The patterns make it possible to further improve the aerodynamic behavior of the annular sealing gasket and therefore the wear behavior of said gasket.

[0015] The implementation of the visual wear indicator which evolves geometrically as a function of the wear of the patterns makes it easier to inspect the wear of the annular sealing joint in service. The visual wear indicator acts as a wear indicator. In addition, the implementation of the indicator arranged partially on the upstream axial end surface and on the radially internal surface of the radially internal annular wall advantageously makes it possible to have information on the evolution of the radial wear of the patterns by observing only the upstream axial end surface of the radially internal annular wall. Indeed, this upstream axial end surface is more easily accessible and analyzable using an endoscopic camera than the radially internal surface of the radially internal annular wall which is closer to the surface cooperating in sealing with the annular sealing joint.

[0016] The features set out in the following paragraphs may, optionally, be implemented independently of one another or in combination with one another.

[0017] Advantageously, the visual wear indicator comprises a hollow-formed cavity which opens respectively onto the radially internal surface and onto the upstream axial end surface of the radially internal annular wall. The change in the circumference of the cavity can then serve as an indicator of the wear of the radially internal surface of the radially internal annular wall.

[0018] The cavity may have a partial spherical shape. By the cavity having a partial spherical shape is meant that the cavity has a truncated spherical shape and not a whole spherical shape. In other words, the cavity may have a spherical cap shape.

[0019] The partial spherical shape of the cavity is preferably centered on a junction edge between the radially internal surface and the upstream axial end surface of the radially internal annular wall.

[0020] The cavity may advantageously have a maximum dimension, for example circumferential, less than or equal to 1 mm.

[0021] The cavity may have a maximum dimension according to the depth less than or equal to the minimum depth according to the radial direction of the patterns.

[0022] The radially inner annular wall may advantageously comprise a plurality of inner wall sectors arranged circumferentially end-to-end around the axis.

[0023] Generally, the annular sealing joint may comprise a plurality of sealing joint sectors distributed circumferentially around the axis, each sealing joint sector comprising a radially inner annular wall sector, also previously referred to as the inner wall sector, and a radially outer annular wall sector, also referred to as the outer wall sector.

[0024] The inner wall sector and the outer wall sector are in particular connected to each other by one of the plurality of elastically deformable members.

[0025] The annular sealing joint may, for example, comprise between eight and twelve sealing joint sectors.

[0026] The external wall sectors can form a monolithic wall, i.e. a single piece.

[0027] The internal wall sectors are preferably distinct and arranged circumferentially end to end.

[0028] Advantageously, at least one internal wall sector may carry a visual wear indicator arranged at a circumferential end of the respective internal wall sector or two visual wear indicators each arranged at a circumferential end of the respective internal wall sector and opposite each other.

[0029] When an internal wall sector carries two visual wear indicators each arranged at a circumferential end of the respective internal wall sector and opposite one another, said two visual wear indicators may have different dimensions. One of said two visual wear indicators may for example have a maximum dimension according to the depth less than or equal to the maximum dimension according to the depth of the other of said two visual wear indicators, for example less than or equal to half the maximum dimension according to the depth of the other of said two visual wear indicators.

[0030] Advantageously, only a portion of the plurality of internal wall sectors may each carry at least one visual wear indicator. In other words, a first portion of the plurality of internal wall sectors comprises at least one, for example one or two visual wear indicators and a second portion of the plurality of inner wall sectors is devoid of a visual wear indicator.

[0031] The first part of the plurality of internal wall sectors comprising at least one visual wear indicator may in particular correspond to the internal wall sectors substantially positioned vertically, at the top and bottom, and horizontally, to the left and right, of the annular sealing joint when the latter is in the operating position.

[0032] The predefined clearance between the annular sealing gasket and the surface cooperating in a sealing manner with the gasket may be between 0.1 and 1.0 mm or even between 0.1 mm and 0.5 mm.

[0033] The elastically deformable member comprises in particular elastically deformable blades extending circumferentially. The blades may in particular be connected at a first circumferential end by a first substantially radial base connected to the radially external annular wall and at a second circumferential end by a second substantially radial base connected to the radially internal annular wall. This configuration makes it possible to improve the control of the radial deformation of the annular sealing joint, and therefore the control of the clearance between the joint and the surface cooperating in a sealing manner with the annular sealing joint.

[0034] The annular sealing gasket may comprise one or between two and five rows of patterns.

[0035] Each of the patterns can advantageously extend in a direction having a component along the axis of the annular sealing joint.

[0036] Each row of patterns notably comprises a plurality of patterns distributed circumferentially.

[0037] The annular sealing gasket may comprise at least two rows of patterns, a first row of patterns opening onto the upstream axial end surface of the radially internal annular wall.

[0038] When the annular sealing gasket comprises two rows of patterns, a second row of patterns is arranged axially downstream of the first row of patterns.

[0039] The minimum depth in the radial direction of the patterns may in particular be between 1.5 times and 2.5 times the predefined clearance for the annular sealing joint. These depth values ​​ensure excellent pressure distribution in the joint, which improves the effectiveness of the joint.

[0040] The patterns may extend in a direction inclined relative to the axis of the annular sealing gasket. In other words, the patterns extend obliquely relative to the axis. This inclination also ensures that the air flow, which possibly has a tangential speed due to the rotation of several elements with which it is possibly in contact, enters the pattern without seeing too great a discontinuity.

[0041] Preferably, the angle of inclination is oriented in the same direction as the tangential velocity of the air flow, or in the direction of rotation of the surface cooperating in a sealing manner with the annular sealing gasket. This makes it possible to improve the performance of the annular sealing gasket.

[0042] For example, an angle of inclination of said inclined direction relative to the axis of the annular sealing joint may be greater than or equal to 30°, for example between 30° and 60°, or even between 30° and 45°.

[0043] The patterns may have a parallelepiped shape.

[0044] According to another aspect, there is provided an aeronautical turbomachine comprising at least one, for example one or more, annular sealing joints as previously described.

[0045] The aeronautical turbomachine advantageously comprises, from upstream to downstream according to the direction of flow of the gases within the turbomachine, a high-pressure compressor, a combustion chamber and a high-pressure turbine. The aeronautical turbomachine further comprises a ventilation circuit configured to convey cooling air taken from the bottom of the combustion chamber to the high-pressure turbine.

[0046] Said ventilation circuit advantageously comprises a first air inlet downstream of the high-pressure compressor. The annular sealing gasket is arranged downstream of the first air inlet in the direction of flow of the cooling air in the ventilation circuit, - downstream of the second air inlet in the direction of flow of the cooling air in the ventilation circuit, the annular sealing gasket being arranged so as to limit air leakage from the housing upstream of the second air inlet, - downstream of the second air inlet in the direction of flow of the cooling air in the ventilation circuit, the annular sealing gasket being arranged so as to limit air leakage from the housing downstream of the second air inlet.

[0047] Downstream means that the annular sealing gasket is arranged fluidically downstream in the direction of flow of the cooling air in the ventilation circuit. Brief description of the drawings

[0048] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:

[0049] [Fig.l] schematically illustrates an example of an aeronautical turbomachine.

[0050] [Fig.2] schematically illustrates a partial view of an example aero turbomachine nautical vessel comprising an annular sealing gasket according to one embodiment.

[0051] [Fig.3] and [Fig.4] schematically illustrate two partial views of an annular sealing gasket according to one embodiment.

[0052] [Fig.5] schematically illustrates a partial view (figure 5A) of the annular sealing gasket according to one embodiment, and two enlarged views (figure 5B and figure 5C) of said partial view. Description of the embodiments

[0053] The present disclosure relates to an annular sealing joint 20 of axis X2. Such an annular sealing joint may in particular be implemented in an aeronautical turbomachine as shown in [Fig.l]. The present document also relates to any type of turbomachine, for example a turboprop or a turbojet for an aircraft.

[0054] In this document, the terms "longitudinal", "radial" and "circumferential" are defined relative to the axis X2 of the annular seal. The terms "inner" and "outer", as well as "internal" and "external", are then defined in the radial direction relative to the axis X2.

[0055] The axis X2 of the annular sealing joint is in particular coincident with the longitudinal axis XI of the turbomachine, the longitudinal axis XI being coincident with the axis of rotation of the low pressure and high pressure rotors of the turbomachine 1.

[0056] The terms upstream and downstream are generally defined, unless otherwise indicated, with respect to the general direction of flow of the gases in the turbomachine along the longitudinal axis XI around which the turbomachine extends.

[0057] [Fig.2] shows a partial view of the turbomachine 1 in a surrounding area of ​​the combustion chamber 5.

[0058] The aeronautical turbomachine comprises, from upstream AM to downstream AV according to the direction of flow of the gases within the turbomachine 1, a high pressure compressor, a combustion chamber 5 and a high pressure turbine.

[0059] The high-pressure turbine comprises in particular a turbine rotor disc arranged at the outlet of the combustion chamber 5. The turbine rotor disc comprises an annular shroud 10 on which are mounted rotor blades 11 driven in rotation by a flow of gas ejected by the combustion chamber 5.

[0060] The aeronautical turbomachine further comprises a ventilation circuit 15 configured to convey cooling air taken from the bottom of the combustion chamber 5 to the high-pressure turbine. The arrows in [Fig. 2] represent directions of air circulation in the ventilation circuit 15 at the level of the surrounding area humming from the combustion chamber.

[0061] More specifically, said ventilation circuit 15 may comprise a first air inlet 16 downstream of the high-pressure compressor. Air taken downstream of the high-pressure compressor in particular passes through the first air inlet 16 according to the circuit C1 shown in [Fig.2].

[0062] The ventilation circuit 15 may comprise a second air inlet 17 opening radially under the combustion chamber 5 and opening into a housing 18 for cooling the high-pressure turbine 6. The air arriving in the housing 18 via the second air inlet 17 may in particular be subdivided and circulate from the housing upstream and downstream towards a purge circuit C2 and towards a cooling circuit C3 for the rotor blades of the high-pressure turbine.

[0063] The ventilation circuit 15 may in particular comprise one or more injectors forming said second air inlet 17. The injectors may be distributed circumferentially around the longitudinal axis XI of the turbomachine.

[0064] In the embodiment shown in [Fig.2], the turbomachine has in particular three seals: a first seal 12 (also designated “CDP”) downstream of the high-pressure compressor, a second seal 13 (also designated “FIS”) and a third seal 14 (“FOS”).

[0065] The first seal 12 is arranged downstream of the first air inlet 16 in the direction of flow of the cooling air in the ventilation circuit 15. By downstream is meant that the first seal is arranged fluidically downstream in the direction of flow of the cooling air in the ventilation circuit 15.

[0066] More precisely, the air taken downstream of the high-pressure compressor passes through the first air inlet 16 then the first seal 12, which is notably located radially under the inlet of the combustion chamber 5.

[0067] The second seal 13 is arranged downstream of the second air inlet 17 in the direction of flow of the cooling air in the ventilation circuit 15. Downstream means that the second seal is arranged fluidically downstream in the direction of flow of the cooling air in the ventilation circuit 15. The second seal 13 is arranged so as to prevent air from leaking from the housing 18 towards the upstream AM of the second air inlet 17.

[0068] For example, the second seal 13 can be located radially under the second air inlet 17.

[0069] The third seal 14 is arranged downstream of the second air inlet 17 in the direction of flow of the cooling air in the ventilation circuit 15. Downstream means that the third seal is arranged fluidically downstream in the direction of flow of the cooling air in the ventilation circuit 15. The third seal 14 is arranged so as to prevent air from leaking from the housing 18 towards the downstream AV of the second air inlet 17, and in particular towards the purge circuit C2.

[0070] In other words, the air taken radially below the combustion chamber passes through the second air inlet 17, opens into the housing 18 before passing upstream AM through the second seal 13 and downstream through the third seal 14.

[0071] For example, the third seal 14 can be located under the first distributor of the high pressure turbine.

[0072] The second seal 13 and the third seal 14 in particular delimit the housing 18.

[0073] It will be noted that the facing surfaces of the first 12, second 13 and third 14 joints are surfaces which can rotate relative to the joint around the axis of the respective joint.

[0074] It should be noted that the first seal 12 can advantageously form the annular sealing gasket 20 according to the present disclosure.

[0075] Reference is now made to Figures 3 and 4 schematically showing two partial views of the annular sealing gasket 20 according to the present disclosure.

[0076] The annular sealing joint 20 according to the present disclosure is configured to cooperate in a contactless sealing manner with a surface 30 which is arranged radially opposite the annular sealing joint 20 and which is rotatable about the axis X2 relative to the annular sealing joint 20.

[0077] Said surface 30 cooperating in a sealing manner with the annular sealing joint is in particular an external surface of a rotor rotating around the axis X2, for example the rotor of the high-pressure turbine.

[0078] In particular, such a contactless seal operates with a low and controlled annular clearance J between the latter and said surface 30 when the latter is rotating. This type of seal is also commonly referred to as a hydrostatic or hydrodynamic seal. Furthermore, this type of seal aims to achieve an adaptation of the clearance during operation. The use of this type of seal then offers the advantage of controlling the leakage flow at the seal, and thus makes it possible to improve the performance of the turbomachine.

[0079] Such an annular sealing joint may in particular be configured to ensure a predefined clearance, also referred to as a “target” clearance. It is then possible for the clearance to vary slightly around the predefined clearance value under conditions of use of the seal. When the seal is in its equilibrium position, the predefined clearance ensures that the air flow passing through the seal is the desired air flow. However, if the clearance increases or decreases, the sealing joint will be returned to the predefined clearance by elastic deformation in the radial direction of the seal.

[0080] More precisely, if the seal clearance becomes smaller than the predefined clearance, the pressure radial under the radially internal surface of the seal induces a displacement of the latter so as to increase the clearance, whereas if the clearance of the seal becomes greater than the predefined clearance, the seal exerts a force greater than the pressure exerted radially under the radially internal surface of the seal so as to bring said surface back to its equilibrium position, i.e. to the predefined clearance.

[0081] This aerodynamic balance makes it possible to prevent at any time the radially internal surface of the annular sealing joint from coming into contact with the radially opposite surface. This avoids the problem of wear which can be encountered with conventional labyrinth seals.

[0082] The predefined clearance J between the annular sealing gasket 20 and the surface 30 cooperating in a sealing manner with the gasket may be between 0.1 and 1.0 mm or even between 0.1 mm and 0.5 mm.

[0083] The annular sealing joint 20 comprises a radially inner annular wall 21 and a radially outer annular wall 22 connected to each other by at least one elastically deformable member 23. In particular, the annular sealing joint 20 comprises a plurality of elastically deformable members 23 arranged circumferentially next to each other.

[0084] The elastically deformable member comprises in particular elastically deformable blades 231, 232 extending circumferentially. The blades 231, 232 may in particular be connected at a first circumferential end by a first substantially radial base 233 connected to the radially external annular wall 22 and at a second circumferential end by a second substantially radial base 234 connected to the radially internal annular wall 21. For example, document WO 2009 / 148787 describes such a seal. This configuration makes it possible to improve the control of the radial deformation of the annular sealing seal 20, and therefore the control of the clearance between the seal 20 and the surface 30 cooperating in a sealing manner with the annular sealing seal 20.

[0085] The annular sealing joint 20 may further comprise a secondary sealing member 25 arranged radially above the radially internal annular wall 21 so as to prevent air from passing axially through the joint above the radially internal annular wall 21.

[0086] The annular sealing joint 20 may comprise a plurality of sealing joint sectors distributed circumferentially around the axis, each sealing joint sector comprising a radially internal annular wall sector 21, also designated internal wall sector 215, and a radially external annular wall sector 21, also designated external wall sector 221. The internal wall sector 215 and the external wall sector 221 are in particular connected to each other by one of the plurality of elastically deformable members 23.

[0087] The annular sealing joint 20 may for example comprise between eight and twelve sealing joint sectors.

[0088] The external wall sectors 221 can form a monolithic wall, that is to say a single piece.

[0089] The internal wall sectors 215 are preferably distinct and arranged circumferentially end to end around the axis X2.

[0090] It will therefore be noted that the radially internal annular wall 21 may comprise a plurality of internal wall sectors 215 distributed circumferentially around the axis X2.

[0091] The internal wall sectors may in particular be spaced circumferentially two by two by a space 214.

[0092] The radially internal annular wall 21 comprises a radially internal surface SI and an upstream axial end surface S2. The radially internal surface SI is in particular opposite the surface 30 cooperating in a sealing manner with the annular sealing joint.

[0093] Furthermore, the annular sealing joint 20 comprises at least one, for example one or between two and five, row of hollow patterns 211, 212 opening onto the radially internal surface SI of the radially internal annular wall 21. The patterns 211, 212 make it possible to improve the aerodynamic behavior of the annular sealing joint 20 and therefore the wear behavior of said joint.

[0094] It is understood that the patterns 211, 212 are in particular separated by non-hollow portions 213 of the radially internal surface SI of the radially internal annular wall 21.

[0095] Each row of patterns comprises in particular a plurality of patterns distributed circumferentially. When the radially inner wall comprises a plurality of inner wall sectors, each row of patterns, for an inner wall sector 215, may comprise more than five patterns, for example between five and twenty patterns, preferably between seven and fifteen patterns, or even between nine and eleven patterns.

[0096] In the example illustrated in Figures 3 and 4, the annular sealing joint 20 comprises two rows of such patterns 211, 212. A first row of patterns 211 opens onto the upstream axial end surface S2 of the radially internal annular wall 21 and a second row of patterns 212 is arranged axially downstream of the first row of patterns 211.

[0097] The minimum depth in the radial direction of the patterns may in particular be between 1.5 times and 2.5 times the predefined clearance J for the annular sealing joint. These depth values ​​ensure excellent pressure distribution in the joint, which improves the effectiveness of the joint.

[0098] The patterns of the first row of patterns 211 may in particular have a depth in the radial direction greater than or equal to the patterns of the second row of patterns 212.

[0099] In particular, each pattern of the first row of patterns 211 may have a planar downstream pattern zone of constant and non-zero depth and an upstream pattern zone in which the depth varies in a decreasing manner towards the downstream while remaining greater than the constant depth of the downstream pattern zone. The downstream zone ensures the general role of the pattern which is to increase the pressure on the radially internal surface SI of the radially internal annular wall when the clearance is smaller than the predefined clearance.

[0100] Furthermore, each of the patterns 211, 212 may in particular extend in a direction having a component along the axis X2.

[0101] In particular, the patterns 211,212 may extend parallel to the axis X2 of the annular sealing gasket.

[0102] The patterns 211, 212 may alternatively extend in a direction inclined relative to the axis X2. In other words, the patterns 211, 212 extend obliquely relative to the axis X2. This inclination also ensures that the air flow, which possibly has a tangential speed due to the rotation of several elements with which it is possibly in contact, enters the pattern without seeing too great a discontinuity.

[0103] Preferably, the angle of inclination is oriented in the same direction as the tangential speed of the air flow, or in the direction of rotation of the surface 30 cooperating in a sealing manner with the annular sealing gasket. This makes it possible to improve the performance of the annular sealing gasket.

[0104] For example, an angle of inclination of said inclined direction relative to the axis X2 of the annular sealing joint may be greater than or equal to 30°, for example between 30° and 60°, or even between 30° and 45°.

[0105] In particular, the patterns 211,212 may have a parallelepiped shape.

[0106] Reference is now made to Figures 5A, 5B and 5C. Furthermore, the radially inner annular wall 21 comprises at least one visual wear indicator 24 of the patterns 211, 212.

[0107] It should be noted that the second seal 13 and the third seal 14 may also have the same characteristics, as previously detailed, as the annular sealing joint according to the present disclosure except for the characteristic concerning the implementation of a visual wear indicator.

[0108] Said at least one visual wear indicator 24 extends over the upstream axial end surface S2 and over the radially internal surface SI of the radially internal annular wall 21. Said at least one visual wear indicator 24 is configured to evolve geometrically as a function of the wear of the patterns 211, 212.

[0109] The implementation of the visual wear indicator which evolves geometrically as a function of the wear of the patterns makes it easier to inspect the wear of the annular sealing joint in service. The visual wear indicator acts as a wear indicator. In addition, the implementation of the indicator arranged partially on the upstream axial end surface and on the radially internal surface of the radially internal annular wall advantageously makes it possible to have information on the evolution of the radial wear of the patterns by observing only the upstream axial end surface of the radially internal annular wall. Indeed, this upstream axial end surface is more easily accessible and analyzable using an endoscopic camera than the radially internal surface of the radially internal annular wall which is closer to the surface 30 cooperating in a sealing manner with the annular sealing joint.

[0110] In particular, the present disclosure makes it possible to inspect said at least one visual wear indicator from the upstream axial end surface of the radially inner annular wall, for example by means of a camera, for example an endoscope camera.

[0111] Said camera may for example be introduced through the first air inlet as defined previously with reference to [Fig.2] in order to allow inspection of the first seal 12 which forms the annular sealing joint according to the present disclosure.

[0112] When the radially inner annular wall 21 comprises a plurality of inner wall sectors 215, at least one inner wall sector 215 may carry a visual wear indicator 24 arranged at a circumferential end 216 of the respective inner wall sector 215 or preferably two visual wear indicators 24 each arranged at an opposite circumferential end 216 of the respective inner wall sector 215, as illustrated in FIG. 5A.

[0113] In addition, it may be advantageous for only a portion of the plurality of internal wall sectors 215 to each carry at least one visual wear indicator 24. In other words, a first portion of the plurality of internal wall sectors comprises at least one, for example one or two visual wear indicators 24 and a second portion of the plurality of internal wall sectors is devoid of a visual wear indicator.

[0114] The first part of the plurality of internal wall sectors comprising at least one visual wear indicator 24 may in particular correspond to the internal wall sectors substantially positioned vertically, at the top and bottom, and horizontally, to the left and right, of the annular sealing joint 20 when the latter is in the operating position.

[0115] Furthermore, the visual wear indicator 24 preferably comprises a hollow-shaped cavity which opens respectively onto the radially internal surface SI and onto the upstream axial end surface S2 of the radially internal annular wall 21. The evolution of the circumference of the cavity can then serve as an indicator of the wear of the radially internal surface SI of the radially internal annular wall 21.

[0116] Preferably, the cavity has a partial spherical shape. By the cavity has a partial spherical shape is meant that the cavity has a truncated spherical shape and not a whole spherical shape. In other words, the cavity may have a spherical cap shape.

[0117] The partial spherical shape of the cavity is preferably centered on a junction edge between the radially internal surface SI and the upstream axial end surface S2 of the radially internal annular wall 21.

[0118] The cavity may in particular have a maximum dimension Dl, for example circumferential, less than or equal to 1 mm.

[0119] The cavity may have a maximum dimension according to the depth D2 less than or equal to the minimum depth according to the radial direction of the patterns 211,212.

[0120] When the radially inner annular wall 21 comprises a plurality of inner wall sectors 215 and one of the inner wall sectors 215 carries two visual wear indicators 24 each arranged at an opposite circumferential end 216 of the respective inner wall sector 215, as illustrated in FIG. 5B, the two visual wear indicators 24 may have different dimensions.

[0121] One of said two visual wear indicators may for example have a maximum dimension according to the depth D2 less than or equal to the maximum dimension according to the depth D2 of the other of said two visual wear indicators, for example less than or equal to half the maximum dimension according to the depth D2 of the other of said two visual wear indicators.

Claims

Claims

1. An annular seal (20) for a turbomachine, the annular seal (20) having an axis (X2) and being configured to cooperate in a contactless sealing manner with a surface (30) which is arranged radially opposite the annular seal (20) and which is rotatable about the axis (X2) relative to the annular seal (20), the annular seal (20) comprising a radially inner annular wall (21) and a radially outer annular wall (22) connected together by at least one elastically deformable member (23), the annular seal (20) comprising at least one row of hollow patterns (211, 212) opening onto a radially inner surface (SI) of the radially inner annular wall (21), the radially inner annular wall (21) comprising at least one visual wear indicator (24) of the patterns (211,212),said at least one visual wear indicator (24) extending over an upstream axial end surface (S2) and over the radially internal surface (SI) of the radially internal annular wall (21), said at least one visual wear indicator (24) being configured to evolve geometrically as a function of the wear of the patterns (211,212).,

2. An annular seal (20) according to claim 1, wherein the visual wear indicator (24) comprises a hollow-formed cavity which opens respectively onto the radially inner surface (S1) and onto the upstream axial end surface (S2) of the radially inner annular wall (21).

3. The annular seal (20) of claim 2, wherein the cavity has a partial spherical shape.

4. An annular sealing gasket (20) according to one of claims 2 or 3, in which the partial spherical shape of the cavity is centered on a junction edge between the radially internal surface (SI) and the upstream axial surface (S2) of the radially internal annular wall (21).

5. Annular sealing gasket (20) according to one of claims 2 to 4, in which the cavity has a maximum dimension (Dl) less than or equal to 1 mm.

6. An annular seal (20) according to one of the preceding claims, wherein the radially inner annular wall (21) comprises a plurality of internal wall sectors (215) arranged circumferentially end-to-end around the axis (X2).

7. An annular seal (20) according to claim 6, wherein at least one inner wall sector (215) carries a visual wear indicator (24) arranged at a circumferential end (216) of the respective inner wall sector (215) or, preferably, two visual wear indicators (24) each arranged at an opposite circumferential end (216) of the respective inner wall sector (215).

8. An annular seal (20) according to one of claims 6 or 7, wherein only a portion of the plurality of inner wall sectors (215) each carries at least one visual wear indicator (24).

9. Aeronautical turbomachine (1) comprising at least one annular sealing gasket (20) according to one of claims 1 to 8.

10. Aeronautical turbomachine (1) according to claim 9, comprising, from upstream (AM) to downstream (AV) in the direction of flow of the gases within the turbomachine, a high-pressure compressor (4), a combustion chamber (5) and a high-pressure turbine (6), the aeronautical turbomachine (1) further comprising a ventilation circuit (15) configured to convey cooling air taken from the bottom of the combustion chamber (5) to the high-pressure turbine (6), said ventilation circuit (15) comprising a first air inlet (16) downstream of the high-pressure compressor (4) and a second air inlet (17) radially under the combustion chamber (5) and opening into a housing (18) for cooling the high-pressure turbine (6),the annular sealing gasket (20) being arranged in one of the following positions: - downstream of the first air inlet (16) in the direction of flow of the cooling air in the ventilation circuit (15). - downstream of the second air inlet (17) in the direction of flow of the cooling air in the ventilation circuit (15), the annular sealing gasket (20) being arranged so as to limit a leak of air from the housing (18) towards the upstream (AM) of the second air inlet (17), - downstream of the second air inlet (17) in the direction of flow of the cooling air in the ventilation circuit (15), the annular sealing gasket (20) being arranged so as to limit a leak of air from the housing (18) towards the downstream (AV) of the second air inlet (17).,

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