FR3086693A1 - SHIM FOR TURBOMACHINE, ASSEMBLY FOR TURBOMACHINE, TURBOMACHINE AND ASSOCIATED METHOD - Google Patents

Abstract

The invention relates to an attached shim (40) for a turbomachine intended to be mounted around a longitudinal axis (X), the turbomachine comprising at least a first blade (20) and a second blade (30) circumferentially adjacent to the first blade (20) mounted on a disc (10), the first blade (20) comprising a first blade (21) equipped with a fin (22) having an upstream face (25) and a downstream face (26), the second blade (30) comprising a second blade (31) equipped with a fin (32) having an upstream face (35) and a downstream face (36), the downstream face (26) of the fin (22) of the first blade (21) being arranged opposite the upstream face (35) of the fin (32) of the second blade (31) so as to form an inter-fin clearance (J), the added shim (40) being intended to be inserted into the inter-fin set (J) and characterized in that it comprises: - means for attaching the attached shim (40) to each of the n trays (22, 32), - a central part (43) having a thickness (e) adapted to be inserted at the level of the inter-fin clearance (J) so as to ensure the junction between the fins (22, 32).

Description

SHIM FOR TURBOMACHINE, ASSEMBLY FOR TURBOMACHINE, TURBOMACHINE AND RELATED METHOD

TECHNICAL FIELD OF THE INVENTION

The invention relates to the general field of aeronautics.

The present invention relates more particularly to a shim for turbomachine blades equipped with fins as well as a method of mounting the shim.

In addition, the invention relates to an assembly for a turbomachine comprising a disc and blades equipped with fins. The invention also relates to a turbomachine comprising such a disc / blade assembly.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

From the prior art, blades of turbomachine blades are known which are provided with lateral fins, called fins. The addition of fins makes it possible to reduce the vibratory load applied to the blades of large blades which are sensitive to vibrations, in particular the blades of a fan or of a turbomachine compressor. Such fins are generally arranged in the radial direction at mid-blade height or at the blade tip.

FIG. 1 represents a fan disk 1 on which are mounted two adjacent blades 2 fitted with fins 6.

With reference to FIG. 1, each blade 2 comprises a blade root 3 engaged in a groove 4 of the disk 1 in order to radially hold the blade 2 on the disk 1. The blade root 3 is extended radially towards the outside by a blade 5 having two lateral faces 5 ′, ie on the lower and upper sides. As can be seen in FIG. 1, a fin 6 extends circumferentially from each lateral face 5 ′ of the blade 5 and is positioned opposite a fin 6 of the blade 2 which is circumferentially adjacent thereto. During the operation of the turbomachine, the circumferentially adjacent fins 6 are intended to be in contact with each other at a contact surface 7.

However, the design of such blades is complex, in particular one of the main difficulties lies in the dimensioning of the fins, in particular the calculation of the clearance between two circumferentially adjacent fins, called internage fins.

Indeed, the inter-fin clearance must be sufficiently low to guarantee good contact between the fins during the operation of the turbomachine and thus ensure the damping of vibrations. In addition, the inter-fin clearance must be large enough so that the blades can be mounted on the disc. Indeed, due to the dispersion of tolerances on the disc and on the blades, it often happens that the inter-fin clearance is zero and that the blades are blocked or overlap which makes mounting the blades on the disc impossible. .

It should be noted that in certain cases where the assembly had still been able to be carried out despite a low inter-fin clearance, the vibratory behavior of the blades caused the blades to wear by vibratory contacts during the operation of the turbomachine.

To date, there are no solutions to resolve the previously mentioned problems.

SUMMARY OF THE INVENTION

The invention makes it possible to solve the aforementioned drawbacks by proposing a solution making it possible to reduce the vibratory load applied to the large blades during the operation of the turbomachine without hindering the mounting of the blades on the disk of the turbomachine.

According to a first aspect, the invention relates to an attached shim for a turbomachine.

The turbomachine comprises at least a first blade and a second blade circumferentially adjacent to the first blade mounted on a disc, the first blade comprising a first blade equipped with a fin having an upstream face and a downstream face, the second blade comprising a second blade equipped with a fin having an upstream face and a downstream face, the downstream face of the fin of the first blade being arranged opposite the upstream face of the fin of the second blade so as to form a clearance, called inter clearance - fins.

In addition, the attached shim includes:

- means for attaching the wedge attached to the fins,

- a central part having a thickness suitable for being inserted at the level of the inter-fin clearance so as to ensure the junction between the fins.

The invention according to the first aspect makes it possible to solve the problems previously mentioned.

In fact, the central part of the added shim is dimensioned according to the internage clearance previously measured. Indeed, the inter-fin play cannot be determined before the blades are mounted on the disc because the inter-fin play can vary, for each pair of blades, by a few tenths of a millimeter following the geometric dispersions of the parts.

Once dimensioned, the added shim is arranged at the level of the inter-fin clearance so as to form a continuous platform with the two fins. The presence of such a platform between the blades makes it possible to stiffen the blades and improve the damping. blades in the face of vibration problems.

In addition, insofar as the fins are no longer intended to be in contact with one another, the dimensioning of the fins is simplified because it is no longer necessary for the inter-fin clearance to be sufficiently small to ensure the contact between the fins during operation of the turbomachine. The internage clearance is, on the contrary, chosen so as to be large enough for the mounting of the blades on the disc is possible and to avoid blocking and overlapping of the blades.

It should also be noted that such an attached shim can be used on blades equipped with fins according to the prior art. Indeed, it suffices to shorten the width of the existing fins so as to allow the passage of the shim added between the fins.

It is therefore a simple and inexpensive solution making it possible to simplify the mounting of the blades provided with fins on a disc while limiting the wear by vibration of the blades during the operation of the turbomachine.

The shim added according to the first aspect of the invention may also have one or more of the characteristics below, considered individually or in all the technically possible combinations.

According to a nonlimiting embodiment, the attachment means are formed by an external platform and an internal platform adapted to surround a portion of the fins, the central part being arranged between the external platform and the internal platform.

According to a nonlimiting embodiment, the external platform and the internal platform delimit a first groove and a second groove on either side of the central part, the first groove and the second groove being adapted to receive by form complementarity, respectively, a portion of the fin of the first blade and a portion of the fin of the second blade.

According to a nonlimiting embodiment, the external platform has an external surface suitable for forming a continuous surface with the external surface of the fin of the first blade and the external surface of the fin of the second blade.

The terms “external” and “internal” designate an element such as a wall or a surface, “radially external” or “radially internal”, namely respectively, distant or close to the axis of rotation of the disc in a radial direction .

According to a nonlimiting embodiment, the internal platform has an internal surface forming a continuous surface with the internal surface of the fin of the first blade and the internal surface of the fin of the second blade.

Furthermore, the invention according to the second aspect of the invention relates to an assembly for a turbomachine comprising a disc on which are mounted at least a first blade and a second blade circumferentially adjacent to the first blade.

The assembly also comprises at least one shim added according to the first aspect of the invention

The assembly according to the second aspect of the invention may also have one or more of the characteristics below, considered individually or in any technically possible combination.

According to a nonlimiting embodiment, the inter-fin clearance is between 5 and 10 mm.

According to a nonlimiting embodiment, the added shim is made of metal or elastomer.

According to a nonlimiting embodiment, the fin of the first blade and / or the fin of the second blade includes (s) a projection configured to axially maintain the shim added between the fins.

According to a third aspect, the invention relates to a turbomachine comprising an assembly according to the second aspect of the invention.

In addition, according to a fourth aspect, the invention relates to a method of assembling a shim added according to the first aspect between a first blade and a second blade of a turbomachine. The first blade comprising a first blade equipped with a fin having an upstream face and a downstream face, the second blade comprising a second blade equipped with a fin having an upstream face and a downstream face, the downstream face of the fin of the first blade being separated from the upstream face of the fin of the second blade by an inter-fin clearance.

The assembly process according to the first aspect comprises the following steps:

- mount the first blade on a disc of the turbomachine,

- hang the shim added to the fin of the first blade by the hooking means, the central part of the shim added having a thickness chosen according to the inter-fin play,

- Mount the second blade on the disc so that the second blade is circumferentially adjacent to the first blade and that the insert is attached to the fin of the second blade to form a junction between the fins at the level of the interplay. fins.

BRIEF DESCRIPTION OF THE FIGURES

The figures are presented for information only and are in no way limiting. The figures show:

- in FIG. 1, a perspective view of a blower disc on which are mounted two adjacent blades equipped with fins,

in FIG. 2a, a perspective view of an assembly for a turbomachine according to an embodiment of the invention,

in FIG. 2b, a top view of the assembly for a turbomachine illustrated in FIG. 2a,

- in FIG. 3, an enlargement of FIG. 2a at the level of the attached shim,

- in FIG. 4, the inter-fin zone of the assembly for a turbomachine according to another embodiment of the invention, before the installation of the insert wedge,

in FIG. 5, the inter-fin zone illustrated in FIG. 4 after the insertion of the attached shim illustrated in FIGS. 2a, 2b and 3,

- In Figure 6, a cross-sectional view of the insert reported according to the invention.

Other characteristics and advantages of the invention will emerge on reading the detailed description which follows, with reference to the appended figures,

DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION

FIGS. 2a and 2b represent an assembly 100 for a turbomachine according to an embodiment of the invention.

With reference to FIGS. 2a and 2b, the assembly 100 for a turbomachine, of longitudinal axis X, comprises a disc 10 on the circumference of which are mounted a first blade 20 and a second blade 30 circumferentially adjacent. Each blade 20 and 30 has a blade root, respectively 24 and 34, which is inserted in a groove 11 formed on the circumference of the disc 10 so as to radially fix the blades 20 and 30 on the disc 10. Naturally, the 'assembly 100 for a turbomachine may comprise more than two blades.

The first blade 20 comprises a blade 21, which will be called the first blade, having a first lateral face 21 ′ and a second lateral face 21 ”, circumferentially opposite, respectively on the lower and upper sides of the blade.

21. The first lateral face 21 'and the second lateral face 21' of the first blade 21 each have a fin 22, 23 circumferentially projecting from said lateral face 21 'and 21'.

In the same way as for the first blade 20, the second blade 30 comprises a blade 31, which will be called the second blade, having a first lateral face 31 'and a second lateral face 31 ”, circumferentially opposite, respectively on the underside and upper surface of the blade 31. The first lateral face 31 'and the second lateral face 31 ”of the second blade 31 each have a fin 32, 33 circumferentially projecting from said lateral face 31' and 31”.

The fins 22 and 23 of the first blade 21 and the fins 32 and 33 of the second blade 31 are arranged radially at mid-height, respectively, of the first blade 21 and the second blade 31. According to another embodiment not shown, the fins 22, 23, 32, 33 are arranged radially at the end of the blade.

In addition, as can be seen in FIGS. 3 and 4, the fins 22 and 23 of the first blade 21 have a point at an upstream or downstream axial end 27 and 28, oriented in the direction of the circumferentially adjacent blade. Likewise, the fins 32 and 33 of the second blade 31 have a point at an upstream or downstream axial end 37 and 38 respectively, oriented in the direction of the circumferentially adjacent blade.

In addition, the fins 22 and 23 of the first blade 21 and the fins 32 and 33 of the second blade 31 each have an upstream face and a downstream face. The terms “upstream” and “downstream” are defined with respect to the direction of flow of the air flow in the turbomachine, i. e. from upstream to downstream, illustrated by an arrow in Figures 2a to 5.

In the following description, the term "fin of the first blade" will mean the fin 22 which projects circumferentially from the second lateral face 21 "of the first blade 21 and by" fin of the second blade ", the fin 32 which projects circumferentially from the first lateral face 31 ′ of the second blade 31.

As can be seen in FIG. 4, the fin 22 of the first blade 21 has an upstream face 25 and a downstream face 26. Similarly, the fin 32 of the second blade has an upstream face 35 and a downstream face 36. The downstream face 26 of the fin 22 of the first blade 21 is arranged opposite the upstream face 35 of the fin 32 of the second blade 31.

A clearance J, called inter-fin clearance, separates the downstream face 26 of the fin 22 of the first blade 21 from the upstream face 35 of the fin 32 of the second blade 31. The inter-fin clearance J is chosen so as to be large enough to ensure, without difficulty, the mounting of the blades 20 and 30 on the disk 10. Advantageously, the inter-fin clearance J is greater than 5mm. In a preferred embodiment, the inter-fin clearance J is between 5 and 10mm.

An attached shim 40, shown in more detail in FIGS. 2, 5 and 6, is arranged at the level of the inter-fin set J so as to form a junction between the fins 22 and 32.

As can be seen in FIG. 6, the added shim 40 generally has an I-shaped profile. More specifically, the added shim 40 comprises an external platform 41, an internal platform 42 and a central part 43 arranged between the external platform 41 and the internal platform 42.

The external platform 41 and the internal platform 42 form means for attaching the insert shim 40 to the fins 22 and 32. In fact, as can be seen in FIG. 6, the external platform 41 and the internal platform 42 delimit a first groove 44 and a second groove 45 on either side of the central part 43. The first groove 44 and the second groove 45 have a shape and dimensions adapted to receive, respectively, a portion of the fin 22 of the first blade 21 and a portion of the fin 32 of the second blade 31. This makes it possible to maintain the attached shim 40 between the fins 22 and 32.

In addition, as can be seen in FIGS. 3 and 5, part of the fins 22 and is covered by the external platform 41 and by the internal platform 42. Advantageously, the external platform 41 has an external surface 411 forming a continuous surface with the external surface 221 of the fin 22 of the first blade 21 and the external surface 321 of the fin 32 of the second blade 31. Likewise, the internal platform 42 has an internal surface 421 forming a continuous surface with the internal surface 222 of the fin 22 of the first blade 21 and the internal surface 322 of the fin 32 of the second blade 31. This makes it possible not to disturb the aerodynamic flow during its passage between the two blades 20 and 30.

The shape and dimensions of the central part 43 of the insert 40 are chosen so that the central part 43 can be inserted at the inter-fin clearance J. To do this, the central part 43 is dimensioned after the mounting the blades 30, 40 on the disc 10 so that its thickness e is adapted to the inter-fin clearance J.

Furthermore, advantageously, the added shim 40 extends over a length Li substantially equal to the length L2 of the downstream face 26 of the fin 22 of the first blade 21 and / or to the length b of the upstream face 35 of the fin 32 of the second blade 31. This allows the added shim 40 to fill the entire inter-fin clearance J and thus ensure the continuity of the junction between the fins 22 and 32 optimally.

Naturally, when the assembly 100 comprises a plurality of vanes equipped with fins, an attached shim 40 can be arranged at each internage set J present between two circumferentially adjacent fins.

In addition, according to the embodiment illustrated in FIG. 5, the fin 22 of the first blade 21 has a first projection 50, circumferentially projecting from the downstream face 26 of said fin 22. The first projection 50 from a upstream end of the fin 22 and which extends perpendicular to the downstream face 26 of the fin 22, in the direction of the fin 32 of the second blade 31.

The fin 32 of the second blade 31 also includes a second projection 51, circumferentially projecting from the upstream face 35 of said fin 32. The second projection 51 extends from an upstream end of the fin 32 and perpendicular to the upstream face 35 of the fin 32 of the second blade 31, in the direction of the fin 22 of the first blade 21.

Advantageously, the first projection 50 and the second projection 51 extend over a distance substantially equal to the inter-fin clearance J.

The projections 50 and 51 form axial stops making it possible to maintain the position of the attached shim 40 between the fins 22 and 32, in particular during the operation of the turbomachine. Indeed, the projections 50, 51 make it possible to prevent the added shim 40 from detaching from the fins 22, 32 by sliding axially outwards.

By "axial" is meant a direction parallel to the longitudinal axis X of the turbomachine.

Advantageously, the added shim 40 is made from a metal material, for example the metal used for the manufacture of the blades 20, 30. This makes it possible to ensure the added shim 40 the same mechanical characteristics as those of the blades 20 , 30, in particular the thermal expansion of the metal. In an alternative embodiment, the insert shim 40 is made from an elastomeric material. The use of such a material makes it possible to produce a compression fitting of the added shim 40 between the fins 22, 32. To do this, the central part 43 of the added shim 40 is dimensioned so that its thickness e is greater than the internage clearance J. Such an assembly makes it possible to improve the seal between the fins 22, 32 and to dampen the relative displacements of the fins 22, 32 during the operation of the turbomachine.

Furthermore, the invention relates to a method of assembling the insert shim 40 between the blades 20, 30 comprising for example the following steps:

mounting the first blade 20 on a disc 10 of the turbomachine,

- hang the shim 40 on the fin 22 of the first blade 20 by the attachment means,

- Mount the second blade 30 on the disc 10 so that the second blade 30 is circumferentially adjacent to the first blade 20 and that the shim 40 is attached to the fin 32 of the second blade to form a junction between the fins 22 and 32 at the level of internageories J.

Claims (10)

1. Insert wedge (40) for a turbomachine intended to be mounted around a longitudinal axis (X), the turbomachine comprising at least a first blade (20) and a second blade (30) circumferentially adjacent to the first blade (20) mounted on a disc (10), the first blade (20) comprising a first blade (21) equipped with a fin (22) having an upstream face (25) and a downstream face (26), the second blade (30) comprising a second blade (31) equipped with a fin (32) having an upstream face (35) and a downstream face (36), the downstream face (26) of the fin (22) of the first blade (21) being arranged opposite the upstream face (35) of the fin (32) of the second blade (31) so as to form an inter-fin set (J), the insert wedge (40) being intended to be inserted into the set inter-fins (J) and characterized in that it comprises: - means for attaching the added shim (40) to each of the fins (22, 32), - A central part (43) having a thickness (e) adapted to be inserted at the level of the inter-fin clearance (J) so as to ensure the junction between the fins (22, 32). 2. Insert wedge (40) according to the preceding claim, characterized in that the attachment means are formed by an external platform (41) and an internal platform (42) adapted to surround part of the fins (22, 32), the central part (43) being arranged between the external platform (41) and the internal platform (42). 3. Insert wedge (40) according to the preceding claim, characterized in that the external platform (41) and the internal platform (42) define a first groove (44) and a second groove (45) on either side of the central part (43), the first groove (44) and the second groove (45) being adapted to receive by complementarity of shape, respectively, a portion of the fin (22) of the first blade (21) and a portion of the fin (32) of the second blade (31). 4. Insert wedge (40) according to claims 2 to 3, characterized in that the external platform (41) has an external surface (411) adapted to form a continuous surface with the external surface (221) of the fin (22) of the first blade (21) and the external surface (321) of the fin (32) of the second blade (31). 5. Insert wedge (40) according to claims 2 to 4, characterized in that the internal platform (42) has an internal surface (421) adapted to form a continuous surface with the internal surface (222) of the fin (22) of the first blade (21) and the internal surface (322) of the fin (32) of the second blade (31). 6. An assembly (100) for a turbomachine comprising a disc (10) on which are mounted at least a first blade (20) and a second blade (30) circumferentially adjacent to the first blade (20), the assembly (100) being characterized in that it comprises at least one attached shim (40) according to one of the preceding claims disposed between a fin (22) of the first blade (20) and a fin (32) of the second blade (30). 7. Assembly (100) according to the preceding claim, characterized in that the inter-fin clearance (J) is between 5 and 10mm. 8. An assembly (100) according to claims 6 to 7, characterized in that the fin (22) of the first blade (21) and / or the fin (32) of the second blade (31) comprises (s) a projection (50, 51) configured to maintain the insert shim (40) axially between the fins (22, 32). 9. Turbomachine characterized in that it comprises an assembly (100) according to one of claims 6 to 8. 10. A method of assembling an added shim (40) according to claims 1 to 5, between a first blade (20) and a second blade (30) of a turbomachine, the first blade (20) comprising a first blade (21 ) equipped with a fin (22) having an upstream face (25) and a downstream face (26), the second blade (30) comprising a second blade (31) equipped with a fin (32) having an upstream face ( 35) and a downstream face (36), the downstream face (26) of the fin (22) of the first blade (21) being separated from the upstream face (35) of the fin (32) of the second blade (31 ) by an inter-fin set (J), the method being characterized in that it comprises the following steps: - mounting the first blade (20) on a disc (10) of the turbomachine, - hang the shim (40) on the fin (22) of the first blade 5 (20) by the attachment means, the central part (43) of the attached shim (40) having a thickness (e) chosen according to the inter-fin clearance (J), - Mount the second blade (30) on the disc (10) so that the second blade (30) is circumferentially adjacent to the first blade (20) and that the shim (40) is hooked to the fin (32 ) of the second blade (30) to form a junction between the fins (22, 32) at the level of the inter-fin set (J).