TURBOMACHINE ASSEMBLY INCLUDING MEANS FOR DETECTING WEAR OF AN ABRADABLE MATERIAL AND TURBOMACHINE INCLUDING SUCH AN ASSEMBLY

Abstract

The invention relates to an assembly for a turbomachine (1), comprising a rotor (21) with longitudinal axis (X), and a stator (19) equipped with a ring (20) of abradable material centered on the longitudinal axis (X) and surrounding the rotor (21), the abradable material being capable of crumbling upon radial contact or friction with a portion of the rotor (21) during its rotation. According to the invention, the assembly includes a detection device (25) comprising at least one induction coil (26) carried by the stator (19) and supplied with an electric current, and at least one magnet (29) mounted on the rotor (21) and generating a magnetic field towards the induction coil, the detection device being configured to measure a change in current intensity in the induction coil as the magnet approaches radially from the induction coil in order to detect the level of crumbling or wear of the abradable material. Figure for the summary: Fig.4

Description

Title of the invention: TURBOMACHINE ASSEMBLY COMPRISING WEAR DETECTION MEANS OF AN ABRADABLE MATERIAL AND TURBOMACHINE COMPRISING SUCH AN ASSEMBLY Technical field of the invention

[0001] The present invention relates to the field of turbomachines, and in particular aircraft. It relates in particular to means for measuring the wear of the abradable materials surrounding the rotors of the turbomachine. Technological background

[0002] It is known to use abradable materials in an aircraft turbomachine so as to ensure dynamic sealing between a stator and a rotor. Indeed, there may be clearances between the rotors and the stators which involve air leaks and which reduce the performance of the turbomachine. The abradable materials, which are friable materials, are generally arranged on a radially internal surface of a stator such as a casing and opposite a rotor of the turbomachine so as to minimize a clearance existing between the rotor and the stator. This rotor may be a fan blade, a compressor or turbine blade, or even a labyrinth-type annular sealing lip.

[0003] In operation, the rotors may come into contact with the abradable material, which may cause it to crumble. Friction of the rotors on the abradable material may be due to expansion of the rotors in operation, misalignment of the rotor, ingestion of foreign objects (FOD), etc. The arrangement of the abradable materials also makes it possible to limit wear on the rotors.

[0004] However, the abradable material can undergo significant friction leading to a reduction in its thickness and its sealing function. It is currently complicated and expensive to carry out wear measurements of abradable materials due to their inaccessibility. The measurement when carried out is often imprecise and the process difficult to repeat, making understanding the wear of the abradable material complex.

[0005] In the event of an exceptional event, such as the loss of a fan, compressor or turbine blade, or the ingestion of foreign objects (FOD), the turbomachine is removed in order to examine it in detail and assess whether it can be put back into service. Abradable materials are examined during these events to detect damage. It is necessary to dismantle the modules and visually inspect them to determine their level of wear, which is long, can delay the return to service of the turbomachine and is expensive.

[0006] There is a need to resolve all or part of the aforementioned drawbacks. Summary of the invention

[0007] The objective of the present invention is to provide a solution for determining the wear of an abradable material and its extent in a simple, efficient and economical manner.

[0008] We achieve this objective in accordance with the invention by means of an assembly for a turbomachine, comprising a rotor with a longitudinal axis, and a stator equipped with a ring of abradable material which is centered on the longitudinal axis and which surrounds the rotor, the abradable material being capable of crumbling in the event of radial contact or friction with at least a portion of the rotor during its rotation about the longitudinal axis, the assembly comprising a detection device comprising at least one induction coil which is carried by the stator and which is powered by an electric current, and at least one magnet, mounted on the rotor, which generates a magnetic field towards the induction coil, the detection device being configured so as to measure a variation in a current intensity in the induction coil when the magnet approaches radially the induction coil in order to detect the level of crumbling or wear of the abradable material.

[0009] Thus, this solution makes it possible to achieve the aforementioned objective. In particular, a coil and a magnet are simple and inexpensive means for determining actual wear within a ring of abradable material following certain events and / or during the operation of the turbomachine in which they are intended to be installed. The configuration of this detection device therefore makes it possible to trace wear via the measurement of the equivalent induction of the electrical circuit. The measurement of wear is non-intrusive and carried out live (in real time).

[0010] The assembly also includes one or more of the following features, taken alone or in combination:

[0011] - several induction coils and several magnets are arranged regularly around the longitudinal axis.

[0012] - each induction coil is independently connected to an electrical circuit integrated at least partly into the stator.

[0013] - the ring comprises several sectors arranged end to end around the long axis gitudinal.

[0014] - the ring is formed from a single annular piece.

[0015] - the abradable material of the ring comprises at least one metallic material.

[0016] - the rotor comprises at least one movable blade facing the ring of material abradable, the moving blade being a fan moving blade, a compressor moving blade or a turbine moving blade.

[0017] - the rotor comprises at least one labyrinth-type annular sealing lip opposite the ring of abradable material, the sealing lip being mounted at one end of a blade of the turbomachine.

[0018] - the rotor comprises a disc centered on the longitudinal axis and on which is mounted the or each magnet.

[0019] - - the magnet is arranged radially at a distance from the induction coil.

[0020] The invention relates to a turbomachine, in particular for an aircraft, comprising at least one assembly as described above and a power source supplying one or each electrical circuit, the or each electrical circuit being intended to be connected to a processing unit of an aircraft.

[0021] The invention finally relates to an aircraft which comprises at least one turbomachine as mentioned above and the processing unit. Brief description of the figures

[0022] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly on reading the detailed explanatory description which follows, of embodiments of the invention given as purely illustrative and non-limiting examples, with reference to the appended schematic drawings in which:

[0023] - [Fig.l] is a partial axial sectional view of an example of a turbomachine with to which the invention applies;

[0024] - [Fig.2] is a partial axial sectional view of an example of a tur assembly turbomachine with rings of abradable materials facing rotor members of the turbomachine according to the invention;

[0025] - [Fig.3] is a partial axial sectional view of an example of a tur assembly bomachine with a ring of abradable material opposite a rotor member according to the invention;

[0026] - [Fig.4] is an axial sectional view of a stator equipped with a ring of material abradable with respect to a rotor according to the invention;

[0027] - [Fig.5] is a radial sectional view of a ring of abradable material surrounding moving blades of a turbomachine and a device for detecting wear of the abradable material according to the invention;

[0028] - [Fig.6] shows an offset of an example of a rotor carrying moving blades coming into contact with a ring of abradable material equipped with at least one part of the detection device according to the invention. Detailed description of the invention

[0029] [Fig. 1] represents a turbomachine 1 with longitudinal axis X to which the invention applies. The turbomachine 1 is a double-flow, double-spool turbojet intended to be mounted on an aircraft, such as an airplane. Of course, the invention can be applied to other types of turbomachine, such as a turboprop, a turboshaft, or it applies generally to a turbomachine which comprises a fan or a propeller which is ducted or not ducted.

[0030] In the present invention, and generally, the terms "upstream" and "downstream" are defined with respect to the circulation of gases or air flows in the turbomachine and here along the longitudinal axis X. The terms "axial" and "axially" are defined with respect to the longitudinal axis X. The terms "external", "external", "internal", "internal" and "radial" are defined with respect to a radial axis Z which extends from the longitudinal axis X and with respect to the distance from the longitudinal axis X. The radial axis is perpendicular to the longitudinal axis.

[0031] The turbomachine 1 comprises, from upstream to downstream, a low-pressure compressor 2, a high-pressure compressor 3, a combustion chamber 4, a high-pressure turbine 5 and a low-pressure turbine 6. Conventionally, the turbomachine 1 comprises a low-pressure shaft 7 which connects the rotor of the low-pressure compressor 2 and the rotor of the low-pressure turbine 6 to form a low-pressure body and a high-pressure shaft 8 which connects the rotor of the high-pressure compressor 3 and the rotor of the high-pressure turbine 5 to form a high-pressure body.

[0032] The turbomachine 1 comprises a fan 9 which is arranged upstream of the low pressure compressor 2. The fan 9 is coupled to the low pressure shaft 7 which drives it in rotation around the longitudinal axis X. A power transmission mechanism (not shown) such as a speed reducer can be interposed between the low pressure shaft 7 and a fan shaft 10 (or the disc 11 of the fan 9). An air flow F which passes through the fan 9 is divided by a separation nozzle 12 into a primary flow F1 circulating in a primary vein 13 passing through the compressor assembly 2, 3, the combustion chamber 4 and the turbine assembly 5, 6 and into a secondary flow F2 circulating radially outside the primary vein 13. In the case of the turbojet engine which is shown in [Fig.l], the secondary air flow F2 circulates in a secondary vein 14.

[0033] The fan 9 comprises moving blades 15 which are carried here by the disc 11 centered on the longitudinal axis X. The moving blades 15 of the fan 9 are surrounded by a fan casing 16 centered on the longitudinal axis X. This fan casing 16 which is a retention casing in the event of breakage of the moving blades 15, is intended to carry a nacelle (not shown) which is connected to an aircraft wing in the present example. The fan casing 16 and a part of the nacelle at least partially delimit the secondary vein 14. Each moving blade 15 extends radially towards the outside through the secondary flow. In particular, each moving blade 15 comprises a root 15a housed in a cell 11a of the disc 11 and a free end 15b facing the fan casing 16.

[0034] Each compressor 2, 3 and each turbine 5, 6 comprises several stages of stator blades and several stages of moving blades which are regularly alternated along the longitudinal axis X. In the present invention, we understand by the term "stator blade" or "fixed blade", a blade which is not driven in rotation around the longitudinal axis X of the turbomachine. In other words, the stator blade is distinct from and opposite a moving blade (rotor blade) of the turbomachine. The stator blades deflect and straighten the primary flow F1 at the outlet of each moving blade located upstream of them. Some of the stator blades may be of variable pitch.

[0035] Each compressor 2, 3 and each turbine 5, 6 comprises an annular casing 17 which is centered on the longitudinal axis X and which surrounds the moving blades 2a, 3a, 5a, 6a and the stator blades 2b, 3b, 6b. The moving blades of the compressor and / or the turbine may comprise a heel which is opposite the annular casing 17. The heel (at a radially internal end) comprises wipers which extend radially outwards (and towards the annular casing 17 in the installation situation).

[0036] Other stator vanes 18 may be arranged downstream of the moving vanes 15 of the fan 9 to straighten the secondary flow F2. These stator vanes 18 are called outlet guide vanes and are abbreviated “OGV” for “Outlet Guide Vane” in English. The stator vanes 18 are arranged transversely in the nacelle substantially in a plane transverse to the longitudinal axis X. These are regularly distributed in this exemplary embodiment around the longitudinal axis X of the turbomachine 1.

[0037] In [Fig. 2] is shown a turbomachine assembly which comprises a ring of abradable material 20 which is arranged so as to surround at least one rotor 21 of the turbomachine. The rotor 21 may be a moving blade of the fan 9, a moving blade 2a of the compressor, etc. The ring of abradable material 20 is arranged opposite each of these moving blades. The ring of abradable material 20 may also be opposite a sealing lip 31 carried by a stator blade 2b at one or other of its ends.

[0038] [Fig. 3] also represents a turbomachine assembly which comprises a ring of abradable material 20 arranged so as to surround the rotor 21 of the turbomachine. The rotor 21 is here a labyrinth-type sealing lip 31. The latter is annular, centered on the longitudinal axis, and extends radially outwards. The sealing lip 31 surrounds the free ends of the moving blades of the turbomachine and can form grooves in the ring of abradable material.

[0039] In [Fig.4], the ring 20 is mounted on a stator 19 of the turbomachine which can be one of the casings of the turbomachine such as the fan casing 16, the annular casing 17 of the compressor or even of the turbine. More precisely, the ring 20 of abradable material covers a radially internal surface 22 (see [Fig.l]) of the stator of the turbomachine. The rotor 21 comprises in this example a disk 32 (centered on the longitudinal axis) and at least one moving blade which may be a moving blade 15 of the fan 9, a moving blade 2a, 3a of the compressor or a moving blade 5a, 6a of the turbine which extends from the disk 32.

[0040] The ring 20 of abradable material is capable of crumbling or wearing away by friction in the event of radial contact with at least one portion of the rotor 21, here one of the moving blades 15, 2a, 3a, 5a, 6a. Indeed, the ring 20 of abradable material is arranged opposite the free ends 15b (comprising wipers or not) of the moving blades 15, 2a, 3a, 5a, 6a so as to reduce the radial clearances between the free ends and the ring 20 of abradable material, and consequently to reduce the air flow leaks which can harm the performance of the turbomachine.

[0041] The ring 20 of abradable material has a thickness el measured between a first surface 23 and a second surface 24 (opposite along the radial axis). In the present example, the first surface 23 is oriented opposite the moving blades and the second surface 24 is secured to the radially internal surface 22 of the stator 19 (casing 16, 17 of the turbomachine).

[0042] The abradable material that makes up the ring 20 advantageously, but not limited to, comprises at least one metallic material or an alloy of metallic material. Examples of a metallic material are aluminum, iron, nickel and chromium. These metallic materials may be in powder form and / or comprise a powder mixture as well as a binder. An example of a powder mixture is sold by the company METCO. The ring of abradable material may also be in the form of a thin metal sheet, for example nickel, oriented towards the blades and carrying a honeycomb. The sheet has a thickness of less than 3 mm. Alternatively, the material may still be a polymer. This polymer may for example be homogeneous and crumble into granules. As a variant, the abradable material may be in the form of a honeycomb known under the name “NID A”.

[0043] Still in [Fig.4], a detection device 25 is configured so as to detect the level of crumbling or wear of the abradable material. The detection device 25 makes it possible to obtain information on a thickness or a quantity of material of the abradable material removed by friction or contact of the rotor, here the moving blades.

[0044] In the present example, the detection device 25 comprises at least a first element which is embedded in the thickness e2 of the stator 19 which supports the ring 20 of abradable material. The first element is powered by an electric current and has a first physical parameter which can vary depending on a second physical parameter acting on the first element.

[0045] Advantageously, but not limited to, the first element comprises an induction coil 26. The coil 26 is connected to an electrical circuit 27 in which the electric current circulates. At least a portion of the latter is integrated into the abradable material. The electrical circuit 27 advantageously, but not limited to, comprises an electrical power source 28 allowing the circulation of the electric current in the electrical circuit and to the induction coil 26. The electrical power source 28 may be arranged in the aircraft or in the turbomachine. Components such as batteries or electrical machines generally generate electricity to power the various equipment of the aircraft or the turbomachine. The electrical circuit 27 may alternatively be powered by a closed circuit within the turbomachine.

[0046] The detection device 25 comprises at least one second element mounted on the rotor 21. The second element comprises the second parameter intended to act on the first element. Advantageously, the second element is a magnetic element and preferably is a magnet 29 which generates a magnetic field on the induction coil 26. The magnet 29 can be mounted on the root of at least one moving blade or on the disc 32 to which the root of the moving blade is attached. In other words, the magnet 29 is arranged radially at a distance from the induction coil 26. Furthermore, the arrangement of the magnet on the rotor or the root makes it possible to minimize the impact on the mechanical strength.

[0047] Advantageously, the induction coil 26 has a dimension such as a radial height which may be a function of the distance between it and the rotor 21, here a free end of the moving blades. The distance will depend on the location of the second element. Furthermore, the dimension of the induction coil 26 will also depend on the power of the magnet 29. In particular, the more powerful the magnet 29, the less “sensitive” the coil will have to be and consequently will have a small dimension.

[0048] The detection device 25 is configured so as to measure a variation in the intensity of the current in the induction coil 26 when the magnet 29 approaches radially the induction coil 26 in order to measure the level of crumbling or wear of the abradable material. Indeed, the inductance of the induction coil 26 is fixed by its geometry. The intensity of the current passing through the coil 26 is a function of the magnetic flux passing through it and its inductance. The link between the relative rotor / stator position in operation and variation in intensity depends on numerous parameters and will have to be calibrated upstream (for example via partial tests).

[0049] In the present example, the electrical power source 28 delivers a current of same voltage (constant voltage) in the induction coil 26. The current intensity is made to vary.

[0050] Advantageously, the magnet 29 has a magnetic force which depends on the parameters chosen from the group comprising the thickness of the different parts (stator, abradable material, position of the magnet itself, position of the coil 26, size of the primary and / or secondary vein, the location of the rotor 21 (in a low pressure compressor, high pressure compressor, low pressure turbine, or enclosure, etc.), etc.

[0051] According to an exemplary embodiment illustrated in [Fig. 5], the detection device 25 comprises several induction coils 26 spaced and distributed regularly around the longitudinal axis X. In this way, the entire surface of the ring of abradable material 20 can be monitored. Advantageously, each induction coil 26 is independent. In this case, each induction coil 26 is connected to an electrical circuit 27 which is also independent of the other electrical circuits. In other words, there are as many induction coils 26 as there are electrical circuits 27. Each electrical circuit 27 is advantageously powered by the same electrical power source 28. A constant voltage is applied to the terminals of each circuit. An azimuthal distribution of several induction coils 26 will make it possible to know the exact angular position of the wear of the abradable material.

[0052] In this example, the detection device 25 also comprises several magnets 29 which are spaced and regularly distributed around the longitudinal axis X. Advantageously, the second elements 29 are regularly distributed. In the example illustrated, there are as many magnets 29 as there are induction coils 26. The identical number of magnets 29 and coils 26 makes it possible to facilitate the path of the magnetic flux from each magnet to the induction coils 26 and to provide high temporal and angular precision of the wear. Of course, a single magnet 29 could be installed on the rotor 21.

[0053] According to an advantageous characteristic, the ring 20 of abradable material is formed from a single annular piece. That is to say that the ring 20 is made in one piece.

[0054] According to an alternative embodiment, the ring 20 of abradable material is in the form of several sectors arranged around the longitudinal axis X. This sector configuration makes it easier to replace and mount the abradable material. The replacement may be carried out during maintenance operations of the turbomachine following events or excessive wear of the abradable material.

[0055] Advantageously, but not limitatively, the abradable material is obtained by projection.

[0056] The or each electrical circuit 27 is connected to a processing unit 30 which is capable of process a signal corresponding to a value of the intensity of the current flowing in at least one induction coil 26. The processing unit 30 is configured to process in real time the signals corresponding to the value of the intensity of the current of the induction coils 26. In other words, it is possible to continuously measure the current passing through the electrical circuit 27 in order to directly measure the rotor / stator distance and therefore the wear of the abradable material as a function of time.

[0057] The processing unit 30 may be the turbomachine computer known by the English acronym FADEC for Full Authority Digital Engine Control. The real-time measurement also makes it possible to determine during operation of the turbomachine at what time (flight phase for example) the maximum wear has occurred. The post-processing is carried out either by the processing unit 30 or by a health monitoring box (known by the English expression Health Monitoring) of the modules of the turbomachine, or by acquisition bays on the bench during development and / or reception tests. The processing unit 30 may comprise a digital model of the ring of abradable material so as to be able to identify the damaged parts or sectors in the abradable material. The electrical source 27 is advantageously connected to the processing unit 30.

[0058] The analysis of the measurement can be carried out after the occurrence of an event. In this case, the recovery of the data relating to the wear of the ring 20 of abradable material is carried out when the aircraft is on the ground. This will make it possible to avoid dismantling the modules and lengthy inspections.

[0059] [Fig.6] illustrates an example of radial contact or friction between a rotor 21 and a stator 19, here for example of at least one moving blade 15, 2a, 3a, 5a, 6a with the ring 20 of abradable material. In this example, the radial contact is due to an offset of the axis of the rotor carrying the moving blades. We see that the free ends 15b of the moving blades, in particular the moving blades located between 3 o'clock and 4 o'clock with reference to a clock face, are close to the abradable material.

[0060] In the case of radial contact, the amplitude of the magnetic field varies. In particular, the amplitude of the magnetic field generated in each coil 26 increases locally, that is to say at the location where the or each magnet 29 approaches the or each induction coil 26. This variation in amplitude, and in particular, the increase in amplitude, creates an increase in the value of the current intensity. The variation in the current intensity makes it possible to measure the level of wear or crumbling of the abradable material.

[0061] It is possible for a predetermined current intensity value to associate a clearance consumption value (minimum distance between the rotor 21 and the stator 19 (with the abradable material)). Current intensity threshold values ​​and / or clearance consumption threshold values ​​can be stored in the processing unit 30 which allows a comparison to be made with the measured value(s). Advantageously, but not limited to, a critical health value can be determined and stored in the memory of the processing unit 30 to intervene on the abradable material.

[0062] In particular, a measuring device 33 such as an ohmmeter makes it possible to continuously measure the current intensity. The measuring device 33 shown in particular in [Fig. 4] is connected to the processing unit 30 and is also connected to the electrical power source 28.

[0063] The measured current intensity values ​​are compared with the threshold values. If the measured value is equal to or greater than the critical health value, this implies that the abradable material at this location exhibits significant wear on this angular sector or location of the ring 20 of abradable material and that intervention is necessary.

[0064] Advantageously, but not limited to, the measured and recorded data are processed in several ways. In a first processing example, the critical health value or the measured current intensity value is transmitted to the pilot via a signal that may be an audible signal or a visual signal. This signal is advantageously transmitted by the processing unit 30 which processes the information relating to the measured values. In a second processing example, the measured values ​​are stored in a memory of the processing unit 30 during operation of the turbomachine (in flight for example) and will then be analyzed once the turbomachine is stopped (on the ground for example). The measured values ​​are extracted by an operator for example from the processing unit 30 and a possible replacement or repair based on the data will be ordered.In a third processing example, the measured values ​​are analyzed by an algorithm which, based on the various comparisons with the reference values ​​measured in the processing unit 30, directly gives the wear status of the abradable material ring 20. The program is advantageously stored in the processing unit 30. In the latter case, there is no human action or intervention.

[0065] The intervention on the ring 20 of abradable material will depend on the critical or significant nature of the wear of the abradable material. The critical or significant nature is evaluated in relation to a critical health value which has been set for the ring 20 of abradable material. This critical health value is determined by a simulation and / or by different tests for each ring 20 of abradable material and each type / version of turbomachine. In the case of excessively damaged abradable material, the turbomachine loses too much power or has a loss of ventilation. This is moving away from the intrinsic properties of the turbomachine. There could be a risk in continuing to fly with a turbomachine equipped with a ring of abradable material with a damaged significant damage or wear.

[0066] In this way, with one or more induction coils distributed around the longitudinal axis X, it is possible to quantify the wear of the abradable material in a precise and reliable manner. The measurement of the current intensity passing through the circuit is carried out continuously and thanks to an upstream calibration, it will be possible to measure the instantaneous approximation between the rotor and the stator as a function of time, and consequently to go back to the maximum wear. When the ring is sectorized, the actually damaged sector is replaced during maintenance if the wear of the abradable material is considered significant. This allows an economic gain and a reduction in the environmental impact. Indeed, the replacement of damaged sectors makes it possible to reduce waste which contributes to the reduction of the environmental impact of the turbomachine. Disassembly and replacement are also facilitated with such a configuration.

Claims

Claims

1. Assembly for a turbomachine (1), comprising a rotor (21) with a longitudinal axis (X), and a stator (19) equipped with a ring (20) of abradable material which is centered on the longitudinal axis (X) and which surrounds the rotor (21), the abradable material being capable of crumbling in the event of radial contact or friction with at least a portion of the rotor (21) during its rotation about the longitudinal axis (X), characterized in that the assembly comprises a detection device (25) comprising at least one induction coil (26) which is carried by the stator (19) and which is powered by an electric current, and at least one magnet (29), mounted on the rotor (21), which generates a magnetic field towards the induction coil (26),the detection device (25) being configured to measure a variation in a current intensity in the induction coil (26) when the magnet (29) approaches radially the induction coil (26) in order to detect the level of crumbling or wear of the abradable material.,

2. Assembly according to the preceding claim, characterized in that several induction coils (26) and several magnets (29) are arranged regularly around the longitudinal axis (X).

3. Assembly according to one of claims 1 or 2, characterized in that each induction coil (26) is independently connected to an electrical circuit (27) integrated at least partly in the stator (19).

4. Assembly according to one of the preceding claims, characterized in that the ring (20) comprises several sectors arranged end to end around the longitudinal axis (X).

5. Assembly according to one of claims 1 to 3, characterized in that the ring (20) is formed from a single annular piece.

6. Assembly according to one of the preceding claims, characterized in that the abradable material of the ring (20) comprises at least one metallic material.

7. Assembly according to one of the preceding claims, characterized in that the rotor (21) comprises at least one moving blade facing the ring (20) of abradable material, the moving blade being a moving blade (15) of the fan (9), a moving blade (2a, 3a) of a compressor or a moving blade (5a, 6a) of a turbine.

8. Assembly according to one of the preceding claims, characterized in that the rotor (21) comprises an annular sealing lip (31) of labyrinth type opposite the ring (20) of abradable material, the sealing lip (31) being mounted at one of the ends of a blade of the turbomachine.

9. Assembly according to any one of the preceding claims, characterized in that the rotor (21) comprises a disc (32) centered on the longitudinal axis and on which the or each magnet (29) is mounted.

10. Turbomachine (1), in particular for an aircraft, comprising at least one assembly according to any one of the preceding claims and an electrical power source (28) supplying one or each electrical circuit (27), the or each electrical circuit being intended to be connected to a processing unit (30) of an aircraft.

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