Protection element for a compressor drum and method for repairing a compressor drum

Abstract

The present invention relates to a protection element (45.1, 45.2) for a compressor drum (20), which is intended to be arranged at least in part between a blade root (25) and the compressor drum (20), comprising: - a first lateral wall (51.1, 51.2) comprising an inner portion (54.1, 54.2) intended to cover an inner rounded portion of a pocket (24), a bearing surface portion (55.1, 55.2) intended to cover a blade root bearing surface of the pocket (24), and an outer portion (56.1, 56.2) intended to cover an outer rounded portion of the compressor drum (20), - a connecting wall (53.1, 53.2) intended to cover an outer face of the compressor drum (20), and - a second lateral wall (52.1, 52.2) comprising a projecting portion (57.1, 57.2) intended to engage with a mounting groove (46.1, 46.2) formed in a vertical face of the compressor drum (20).

Description

DESCRIPTION TITLE : PROTECTIVE ELEMENT FOR A COMPRESSOR DRUM AND METHOD FOR REPAIRING A COMPRESSOR DRUM

[0001] The present invention relates to a protective element for a low-pressure compressor drum of a turbomachine. The invention finds a particularly advantageous application for the repair of a used low-pressure compressor drum. However, the invention may also be implemented at the end of production with a low-pressure compressor drum in a new condition.

[0002] The operating principle of a turbomachine fan is to compress the air entering the engine. A large part of this air constitutes the secondary flow and the other part constitutes the primary flow. The latter passes through a low-pressure compressor attached to the fan, through a high-pressure compressor, through the combustion chamber, through the high-pressure turbine and, finally, through the low-pressure turbine before being ejected.

[0003] The compression achieved by the blower is carried out in two phases. In the first phase, a moving blade accelerates the air particles by deflecting them relative to the engine axis. The moving blade comprises a plurality of blades mounted on a cylindrical hub called a "fan disc" driven in rotation by the low-pressure turbine.

[0004] In a second phase, a fixed vane slows the air particles and transforms part of their speed into pressure. This fixed vane is called an OGV (Outlet Guide Vane) or "rectifier" because it brings the air flow, accelerated by the moving vane, back into the engine axis.

[0005] The same principle is applied by the low-pressure compressor located downstream of the blower. The low-pressure compressor has moving blades mounted on a cylindrical part called the compressor drum as well as rectifiers consisting of fixed blades. Depending on the In turbomachines, low pressure compressors can have 3 to 5 stages, a compressor stage being composed of a wheel of moving blades and a grid of corresponding rectifiers.

[0006] As illustrated in Figure 1, for each stage of the low-pressure compressor, the moving blades 1 are installed in a corresponding cell 2 of the compressor drum 4 via an introduction window 3 according to the following steps: i - a first blade 1 is inserted, following the arrow F1, into the cell 2 through the introduction window 3. ii - once the blade 1 is inserted, it is shifted tangentially following the arrow F2 by sliding it into the cell 2 in order to release the introduction window 3. The first blade 1 is then installed. ill - the next blade can then be inserted and the operation repeated until all the blades 1 are installed inside the cell 2.

[0007] When the turbomachine and therefore the compressor drum 4 are rotated, the moving blades 1 are retained radially by the bearing surfaces 5 of the cell 2, as illustrated in FIG. 2. Such an assembly of the moving blades 1 in a cell 2 of the compressor drum 4 is a conventional and proven installation of the state of the art.

[0008] Nevertheless, micro-displacements of the blades 1 inside the cell 2 at the location of a contact surface between the bearing surfaces 6 of the blade roots 7 and the bearing surfaces 5 of the cell 2 can locally wear said bearing surfaces 5 of the cell 2.

[0009] This wear represented by the broken lines in Figure 2 is likely to reduce the radial clearances located above the moving blades 1, which creates a risk of uncontrolled penetration of the moving blades 1 into the abradable seals. The wear also risks creating axial offsets of the moving blades 1 likely to interfere with the fixed blades. In addition, the position differences between the moving blades 1 impact the balancing of the compressor drum 4.

[0010] The mounting of moving blades 1 on a worn compressor drum 4 may also be affected, insofar as there is a risk that a moving blade 1 is located between an unworn part and a worn part of the bearing surfaces 5 of the compressor drum 4.

[0011] Significant wear may also affect the mechanical strength of the low pressure compressor drum 4, which may break during operation.

[0012] The invention aims to effectively remedy the aforementioned drawbacks by proposing a protective element for a compressor drum intended to be arranged at least partly between a blade root and the compressor drum comprising: - a first side wall comprising an internal portion intended to cover an internal rounded portion of a cell of the compressor drum, a bearing portion intended to cover a blade root bearing of the cell, and an external portion intended to cover an external rounded portion of the compressor drum, - a connecting wall intended to cover an external face of the compressor drum, and - a second side wall comprising a projecting portion intended to cooperate with a mounting groove made in a vertical face of the compressor drum.

[0013] The invention thus makes it possible to restore the contact interface between the drum cell surfaces and the moving blades. The invention therefore makes it possible to install moving blades in the compressor drum in the same position as on a new drum coming out of production.

[0014] According to one embodiment of the invention, the connecting wall is elastically deformable so as to allow mounting of the protective element on the compressor drum.

[0015] According to one embodiment of the invention, said protective element comprises a recess intended to be arranged opposite a portion of a blade introduction window made in the compressor drum.

[0016] According to one embodiment of the invention, said protective element comprises at least one recess intended to be arranged opposite a portion of a blade lock introduction window.

[0017] According to one embodiment of the invention, the connecting wall comprises at least one opening for the passage of a projecting portion of a passage zone of a sealing joint.

[0018] According to one embodiment of the invention, said protective element consists of a folded sheet having a thickness of between 0.2 mm and 0.4 mm.

[0019] According to one embodiment of the invention, said protective element is made of a nickel-based metallic material.

[0020] According to one embodiment of the invention, the bearing portion is covered with a layer of lubricating varnish.

[0021] According to one embodiment of the invention, a tangential length of the protection element is greater than a tangential length of a blade platform and less than or equal to a tangential length of five blade platforms.

[0022] The invention also relates to a method for repairing a compressor drum comprising: - a machining step intended to remove wear from the bearing surfaces of the compressor drum so as to define a cell having upstream and downstream bearing surfaces with regular surfaces, - a step of machining two mounting grooves respectively upstream and downstream of the cell, and - a step of installing an upstream protection element and a downstream protection element in such a way that the protection elements cooperate respectively with a corresponding mounting groove made in the compressor drum and cover the upstream and downstream surfaces of the cell.

[0023] According to one implementation of the invention, said method further comprises a step of machining a passage zone of a seal so as to have an alternation of projecting portions and flat portions to facilitate installation of a protective element on the compressor drum.

[0024] According to one implementation of the invention, each protective element is installed by applying a radial force to the protective element, such that a connecting wall of the protective element is deformed to allow a projecting portion of each protective element to cooperate with a corresponding mounting groove before returning to its initial planar shape so as to cover a corresponding external face of the compressor drum.

[0025] According to one implementation of the invention, said method further comprises a step of machining external faces of the compressor drum located respectively upstream and downstream of the cell.

[0026] The present invention will be better understood and other characteristics and advantages will become apparent upon reading the detailed description which follows, comprising embodiments given for illustrative purposes with reference to the appended figures, presented as non-limiting examples, which may serve to complete the understanding of the present invention and the description of its embodiment and, where appropriate, contribute to its definition, in which:

[0027] [Fig. 1] Figure 1, already described, is a perspective view illustrating the mounting of the blades inside a low pressure compressor drum cell;

[0028] [Fig. 2] Figure 2, already described, is a cross-sectional view of a cell in a compressor drum illustrating wear of the bearing surfaces by the blade root;

[0029] [Fig. 3] Figure 3 is a longitudinal sectional view of a front part of a turbomachine;

[0030] [Fig. 4] Figure 4 is a perspective view of a low pressure compressor drum on which the repair method according to the invention is implemented;

[0031] [Fig. 5] Figure 5 is a cross-sectional view of a cell of the low pressure compressor drum on which the repair method according to the invention is implemented;

[0032] [Fig. 6a] Figure 6a is a partial perspective view of a cell of the compressor drum after a machining step of the repair method according to the invention;

[0033] [Fig. 6b] Figure 6b is a detailed perspective view of the cell of Figure 6a showing the machining of a groove for receiving a seal;

[0034] [Fig. 7a] Figure 7a is a perspective view of an upstream protection element for a compressor drum according to the invention having a standard configuration;

[0035] [Fig. 7b] Figure 7b is a perspective view of a downstream protection element for a compressor drum according to the invention having a standard configuration;

[0036] [Fig. 8a] Figure 8a is a perspective view of an upstream protection element for a compressor drum according to the invention having a "lock" type configuration;

[0037] [Fig. 8b] Figure 8b is a perspective view of a downstream protection element for a compressor drum according to the invention having a "lock" type configuration;

[0038] [Fig. 9] Figure 9 shows the different stages of installation of a protective element according to the invention inside a cell of a low pressure compressor drum;

[0039] [Fig. 10] Figure 10 is a perspective view of a cell of a low pressure compressor drum in which protective elements according to the invention have been installed;

[0040] [Fig. 11] Figure 11 is a perspective view illustrating the installation of blades inside a low pressure compressor drum cell in which protective elements according to the invention have been installed;

[0041] [Fig. 12] Figure 12 is a perspective view illustrating the positioning of the upstream and downstream protection elements according to the invention between the bearing surfaces of a blade and the bearing surfaces of a low-pressure compressor drum cell.

[0042] It should be noted that, in Figures 3 to 12, the structural and / or functional elements common to the different embodiments have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

[0043] In the remainder of the description, the terms "internal" and "external" are understood with reference to a radial direction relative to the axis X1 of the compressor drum, i.e. an "internal" face is a radially internal face while an "external" face is a radially external face, such that the internal face is closer to the axis X1 of the drum than the external face.

[0044] Figure 3 shows the front part of a turbomachine 10 comprising a fan 11 provided with a moving blade 12 intended to accelerate the air particles, by deflecting them relative to the axis of the engine. The moving blade 12 comprises a plurality of blades 13 mounted on a cylindrical hub 14 called a "fan disc" driven in rotation by the low pressure turbine.

[0045] A fixed vane 15 located downstream of the moving vane 12 slows down the air particles and transforms part of their speed into pressure. This fixed vane 15 is called OGV (for "Outlet Guide vane") in English or "rectifier" because it brings the air flow, accelerated by the moving vane 12, back into the axis of the engine.

[0046] A low pressure compressor 18 comprises moving blades 19 mounted on a cylindrical part called a low pressure compressor drum 20 as well as rectifiers 21 consisting of fixed blades. Depending on the configuration of the turbomachine 10, the low pressure compressor 18 may comprise 3 to 5 stages, a compressor stage being composed of a wheel of moving blades 19 and a grid of corresponding rectifiers 21.

[0047] The compressor drum 20 of axis X1 shown in FIG. 4 has a cylindrical shape. The compressor drum 20 comprises a plurality of cells 24 corresponding to the number of stages of the low-pressure compressor 18. Each cell 24 is a circumferential groove extending along a circumference of the drum 20 and intended to receive blade roots 25, such that the blades 19 are angularly spaced regularly along a circumference of the compressor drum 20. The compressor drum 20 comprises a fixing interface 22 with the hub 14 of the fan.

[0048] As can be seen in Figure 5, a cell 24 is delimited by an upstream blade root bearing surface 26.1 against which a blade root bearing surface 25 of corresponding shape abuts, an upstream internal rounded portion 27.1, a cell bottom 28, a downstream internal rounded portion 27.2 and a downstream blade root bearing surface 26.2 against which a downstream blade root bearing surface 26.2 of corresponding shape abuts. In cross-sectional view, the upstream 26.1 and downstream 26.2 blade root bearing surfaces form an angle no relative to the cell bottom 28, so that the cell 24 generally has a trapezoidal shape complementary to that of a blade root 25. This makes it possible to ensure radial retention of the blades 19 when the compressor drum 20 is rotating.

[0049] An upstream external rounded portion 29.1 and a downstream external rounded portion 29.2 are located respectively in an extension of the upstream 26.1 and downstream 26.2 blade root span of the corresponding cell 24.

[0050] The compressor drum 20 also comprises an upstream external face 30.1 and a downstream external face 30.2. The external faces 30.1, 30.2 have an annular shape with an axial orientation relative to the axis X1. The external faces 30.1, 30.2 are located radially outwardly of the compressor drum 20 relative to the axis X1.

[0051] An upstream vertical face 31.1 and a downstream vertical face 31.2 each extend in a radial plane relative to the axis X1 of the compressor drum 20. Each vertical face (upstream 31.1 respectively downstream 31.2) is located on the side opposite the corresponding face comprising the external rounded portion (upstream 29.1 respectively downstream 29.2), the blade root surface (upstream 26.1 respectively downstream 26.2), and the internal rounded portion (upstream 27.1 respectively downstream 27.2).

[0052] The upstream vertical face 31.1, the upstream external face 30.1, the upstream external rounded portion 29.1, the upstream blade root bearing surface 26.1, and the upstream internal rounded portion 27.1 are made in an upstream wall 35.1 of the cell 24. The downstream vertical face 31.2, the downstream external face 30.2, the downstream external rounded portion 29.2, the downstream blade root bearing surface 26.2, and the downstream internal rounded portion 27.2 are made in a downstream wall 35.2 of the cell 24.

[0053] As can be seen in Figures 6a and 6b, the compressor drum 20 further comprises an introduction window 36 for the blade root 25 as well as two introduction windows 37 for blade locks arranged on either side of the introduction window 36 for the blade root 25.

[0054] Furthermore, a passage zone 40 of a seal is defined by two circumferential walls 41 originating from the external face 30.1 between which extends a groove 42 for receiving the seal (not shown). In the example shown, the seal is intended to be arranged upstream of the cell 24. However, depending on the stage of the low-pressure compressor 18, the seal may be installed upstream or downstream of the cell 24.

[0055] A method of repairing a used low pressure compressor drum 20 is described below.

[0056] A step of machining the drum 20 is carried out, intended to eliminate wear on the bearing surfaces 26.1, 26.2 of the compressor drum 20 so as to define a cell 24 having upstream 26.1 and downstream 26.2 bearing surfaces having regular surfaces. The machining is preferably carried out so that the cell 24 has an axisymmetric configuration, excluding the blade or lock introduction windows 36, 34.

[0057] A machining step is also carried out on the compressor drum 20 to allow the installation of the protective elements 45.1, 45.2 described in more detail below. Following this operation, two mounting grooves 46.1, 46.2 are produced respectively upstream and downstream of the cell 24 in the upstream vertical face 31.1 and in the downstream vertical face 31.2.

[0058] A step of machining the upstream 30.1 and downstream 30.2 external faces of the low-pressure compressor drum 20 is also carried out so as to obtain regular surfaces. In particular, the passage zone 40 of the seal is machined so as to form an alternation of projecting portions 48 and flat portions 49 to facilitate installation of a protective element 45.1, 45.2 on the low-pressure compressor drum 20.

[0059] Once the machining steps are completed, an upstream protection element 45.1 and a downstream protection element 45.2 are installed in such a way that the protection elements 45.1, 45.2 cooperate respectively with a corresponding mounting groove 46.1, 46.2 made in the drum 20 and respectively cover the upstream bearing surface 26.1 and the downstream bearing surface 26.2 of the cell 24.

[0060] The protective elements 45.1, 45.2 thus fill the gap between the bearing surfaces of the moving blade 19 and the bearing surfaces of the cell 24 of the compressor drum 20, as shown in Figure 12.

[0061] More precisely, each protection element 45.1, 45.2 (upstream or downstream) is intended to be arranged at least partly between a blade root 25 and the compressor drum 20.

[0062] According to a standard upstream geometry shown in Figure 7a and 12, the upstream protection element 45.1 also called "upstream foil" comprises a first upstream side wall 51.1, a second upstream side wall 52.1 and an upstream connecting wall 53.1 providing the connection between the first upstream side wall 51.1 and the second upstream side wall 52.1.

[0063] The first upstream side wall 51.1 comprises an upstream internal portion 54.1 intended to cover the upstream internal rounded portion 27.1 of a cell 24, an upstream bearing portion 55.1 intended to cover an upstream blade root bearing 26.1 of the cell 24 and an upstream external portion 56.1 intended to cover an upstream external rounded portion 29.1 of the drum located in an extension of the upstream blade root bearing 26.1. The upstream bearing portion 55.1 forms a non-zero angle relative to the upstream connecting wall 53.1.

[0064] The upstream connecting wall 53.1 is intended to cover the upstream external face 30.1 of the compressor drum 20. The upstream connecting wall 53.1 has a planar shape. The upstream connecting wall 53.1 is elastically deformable so as to allow mounting of the upstream protection element 45.1 on the compressor drum 20. The upstream connecting wall 53 comprises at least one opening 60 for the passage of a projecting portion 48 of the seal passage zone 40. The number of passage openings depends on the configuration of the seal passage zone 40 at the location where the upstream protection element 45.1 is positioned.

[0065] The second upstream side wall 52.1 comprises an upstream projecting portion 57.1 intended to cooperate with the upstream mounting groove 46.1 made in an upstream vertical face 31.1 of the drum. The upstream projecting portion 57.1 extends towards the inside of the upstream protection element 45.1. The second upstream side wall 52.1 has an S shape. The upstream protection element 45.1 has an axisymmetry at the level of the cell 24.

[0066] Similarly, according to a standard downstream geometry shown in Figures 7b and 12, the downstream protection element 45.2 comprises a first downstream side wall 51.2, a second downstream side wall 52.2 and a downstream connecting wall. 53.2 providing the connection between the first downstream side wall 51.2 and the second downstream side wall 52.2.

[0067] The first downstream side wall 51.2 comprises a downstream internal portion 54.2 intended to cover the downstream internal rounded portion 27.2 of a cell 24, a downstream bearing portion 55.2 intended to cover a downstream blade root bearing 26.2 of a cell 24 and a downstream external portion 56.2 intended to cover the downstream external rounded portion 29.2 of the drum 20 located in an extension of the downstream blade root bearing 26.2. The downstream bearing portion 55.2 forms a non-zero angle relative to the downstream connecting wall 53.2.

[0068] The downstream connecting wall 53.2 is intended to cover the downstream external face 30.2 of the compressor drum 20. The downstream connecting wall 53.2 has a planar shape. The downstream connecting wall 53.2 is elastically deformable so as to allow mounting of the downstream protection element 45.2 on the compressor drum 20.

[0069] The second downstream side wall 52.2 has a downstream projecting portion 57.2 intended to cooperate with the downstream mounting groove 46.2 made in the downstream vertical face 31.2 of the drum 20. The downstream projecting portion 57.2 extends towards the inside of the downstream protection element 45.2. The second downstream side wall 52.2 has an S shape. The downstream protection element 45.2 has an axisymmetry at the level of the cell 24.

[0070] According to a lock-type geometry shown in Figure 8a, the upstream protection element 45.1 comprises an upstream recess 63.1 intended to be arranged opposite an upstream portion of a blade introduction window 36 made in the low-pressure compressor drum 20. The upstream recess 63.1 is made in the upstream external portion 56.1 and in the upstream connecting wall 53.1 of the upstream protection element 45.1. The upstream protection element 45.1 also comprises recesses 64.1 each intended to be arranged opposite a portion of a blade lock introduction window 37.

[0071] Similarly, according to a lock-type geometry shown in Figure 8b, the downstream protection element 45.2 comprises a downstream recess 63.2 intended to be arranged opposite a downstream portion of a blade introduction window 36 made in the compressor drum 20. The downstream recess 63.2 is made in the downstream external portion 56.2 and in the downstream connecting wall 53.2 of the downstream protection element 45.2. The downstream protection element 45.2 also comprises recesses 64.2 intended to be arranged opposite a portion of a blade lock introduction window 37.

[0072] Preferably, each protective element 45.1, 45.2 is made of a folded sheet having a thickness of between 0.2 mm and 0.4 mm. The thickness of the sheet can be adapted to the repair requirement so as to compensate for the level of wear of the cell 24. The thin sheet is sufficiently deformable to allow the protective element 45.1, 45.2 to match the shape of the machined cell 24.

[0073] Each protective element 45.1, 45.2 is made of a nickel-based metallic material, in particular of the inconel type (registered trademark). Such a material provides superior wear resistance to titanium and makes it possible to produce parts of low thicknesses that are sufficiently rigid to withstand the matting stresses at the interface between the moving blades 19 and the compressor drum 20.

[0074] The bearing portion 55.1, 55.2 may be covered with a layer of lubricating varnish. This makes it possible to improve the contact conditions between a moving blade 19 and the corresponding bearing 26.1, 26.2 of the cell 24 to maximize the service life of the compressor drum 20.

[0075] Preferably, a tangential dimension of the protection element 45.1, 45.2 is such that several moving blades 19, in particular between 1 and 5, can be in contact with the latter. Advantageously, a tangential length of the protection element 45.1, 45.2 is greater than a tangential length of a blade platform 65 (see FIG. 11) in order to prevent the bearing surfaces of a blade 19 from being in contact with two neighboring protection elements 45.1, 45.2, causing a contact discontinuity between the moving blade 19 and the compressor drum 20.

[0076] Furthermore, the tangential length of the protection element 45.1, 45.2 is less than or equal to a tangential length of five blade platforms 65 in order to allow deformation of the protection element 45.1, 45.2 for its mounting on the compressor drum 20. Indeed, a greater length of the protection element 45.1, 45.2 would increase its rigidity which would prevent to obtain the deformation necessary for its mounting on the compressor drum 20.

[0077] The various steps for mounting the protective element 45.1 are described below, with reference to Figure 9. The steps are identical with the protective element 45.2 except for the mounting direction.

[0078] As illustrated by the left view, the protective element 45.1 is positioned according to the arrow F1, such that the internal portion 54.1 and the bearing portion 55.1 come respectively opposite the internal rounded portion 27.1 and the bearing 26.1 of a cell 24. The connecting wall 53.1 has a flat shape before its assembly.

[0079] As illustrated by the central view, a radial force is applied to the protection element 45.1, such that the connecting wall 53.1 is deformed to allow the projecting portion 57.1 of the protection element 45.1 to cooperate with the mounting groove 46.1.

[0080] As illustrated by the right-hand view, the connecting wall 53.1 then returns to its initial planar shape so as to cover the external face 30.1 of the compressor drum 20. Thus, the upstream 45.1 or downstream 45.2 protection element is held respectively around an upstream 35.1 or downstream 35.2 wall of a cell 24.

[0081] As illustrated in Figure 10, a plurality of upstream protection elements 45.1 are thus arranged edge to edge to follow the circumference of an upstream wall 35.1 of the cell 24 of the drum. Similarly, a plurality of downstream protection elements 45.2 are arranged edge to edge to follow the circumference of a downstream wall 35.2 of the cell 24 of the drum. The geometry of the protection element 45.1, 45.2 (standard or lock) is adapted according to the configuration of the cell 24 in the area of ​​installation of the protection element 45.1, 45.2.

[0082] As shown in Figure 11, the blades 19 can then be installed inside the cell 24 via the window introduction 36 according to the method previously described with reference to figure 1. Vane locks are then put in place via the windows 37 to prevent the vanes 19 from moving inside the cell 24.

[0083] The invention also relates to the assembly formed by a protection element 45.1, 45.2 and the compressor drum 20.

[0084] Of course, the various features, variants and / or embodiments of the present invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive.

[0085] Furthermore, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms and other variants that may be envisaged by those skilled in the art within the scope of the present invention and in particular all combinations of the different modes of operation described above, which may be taken separately or in combination.

Claims

CLAIMS Protective element (45.1, 45.2) for a compressor drum (20) intended to be arranged at least partly between a blade root (25) and the compressor drum (20) characterized in that it comprises: - a first side wall (51.1, 51.2) comprising an internal portion (54.1, 54.2) intended to cover an internal rounded portion (27.1, 27.2) of a cell (24) of the compressor drum (20), a bearing portion (55.1, 55.2) intended to cover a blade root bearing (26.1, 26.2) of the cell (24), and an external portion (56.1, 56.2) intended to cover an external rounded portion (29.1, 29.2) of the compressor drum (20), - a connecting wall (53.1, 53.2) intended to cover an external face (30.1, 30.2) of the compressor drum (20), and - a second side wall (52.1, 52.2) comprising a projecting portion (57.1, 57.2) intended to cooperate with a mounting groove (46.1, 46.2) made in a vertical face (31.1, 31.2) of the compressor drum (20). Protective element according to claim 1, characterized in that the connecting wall (53.1, 53.2) is elastically deformable so as to allow mounting of the protective element (45.1, 45.2) on the compressor drum (20). Protective element according to claim 1 or 2, characterized in that it comprises a recess (63.1, 63.2) intended to be arranged opposite a portion of a blade introduction window (36) made in the compressor drum (20). Protective element according to any one of claims 1 to 3, characterized in that it comprises at least one recess (64.1, 64.2) intended to be arranged opposite a portion of a blade lock introduction window (37).Protective element according to any one of claims 1 to 4, characterized in that the connecting wall (53.1, 53.2) comprises at least one opening (60) for the passage of a projecting portion (48) of a passage zone (40) of a sealing joint. Protective element according to any one of claims 1 to 5, characterized in that it is constituted by a folded sheet having a thickness of between 0.2 mm and 0.4 mm. Protective element according to any one of claims 1 to 6, characterized in that it is made of a nickel-based metallic material. Protective element according to any one of claims 1 to 7, characterized in that the bearing portion (55.1, 55.2) is covered by a layer of lubricating varnish. Protective element according to any one of claims 1 to 8, characterized in that a tangential length of the protective element (45.1, 45.2) is greater than a tangential length of a blade platform (65) and less than or equal to a tangential length of five blade platforms (65). Method for repairing a compressor drum (20) characterized in that it comprises: - a machining step intended to remove wear from the bearing surfaces (26.1, 26.2) of the compressor drum (20) so as to define a cell 24 having upstream and downstream bearing surfaces (26.1, 26.2) having regular surfaces, - a step of machining two mounting grooves (46.1, 46.2) respectively upstream and downstream of the cell (24), and - a step of installing an upstream protection element (45.1) and a downstream protection element (45.2) such that the protection elements (45.1, 45.2) cooperate respectively with a corresponding mounting groove (46.1, 46.2) made in the compressor drum (20) and cover the upstream and downstream surfaces (26.1, 26.2) of the cell (24). Method according to claim 10, characterized in that it further comprises a step of machining a passage zone (40) of a seal so as to have an alternation of projecting portions (48) and flat portions (49) to facilitate installation of a protection element (45.1, 45.2) on the compressor drum (20). Method according to claim 10 or 11, characterized in that each protective element (45.1, 45.2) is installed by applying a radial force to the protective element (45.1, 45.2), such that a connecting wall (53.1, 53.2) of the protective element (45.1, 45.2) is deformed to allow a projecting portion (57.1, 57.2) of each protective element (45.1, 45.2) to cooperate with a corresponding mounting groove (46.1, 46.2) before returning to its initial planar shape so as to cover a corresponding external face (30.1, 30.2) of the compressor drum (20). Method according to any one of claims 10 to 12, characterized in that it further comprises a step of machining external faces (30.1, 30.2) of the compressor drum (20) located respectively upstream and downstream of the cell (24).

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