FR3101107A1 - DAWN FOR AN AIRCRAFT TURBOMACHINE - Google Patents

Abstract

Blade for an aircraft turbomachine, this blade comprising a blade (26) comprising an intrados and an extrados which are interconnected by a leading edge and by a trailing edge (26b), the blade comprising a first portion ( P1) made from a first material and defining said leading edge as well as parts of the lower surface and upper surface, and a second portion (P2) made from a second material, and defining said trailing edge as well as d other parts of the lower surface and the upper surface, characterized in that said first portion extends over more than 75% of a chord of the blade. Figure for abstract: Figure 6

Description

DAWN FOR AN AIRCRAFT TURBOMACHINE

Technical field of the invention

The present invention relates to a blade for an aircraft turbomachine.

Technical background

An aircraft turbomachine blade can be a rotor or stator blade and conventionally comprises a blade comprising an upper surface and a lower surface which are interconnected by leading and trailing edges of the gases flowing in the turbomachine.

The blades of the blades are conventionally made of a metal alloy, for example by foundry or by a so-called "lost wax" method, well known to those skilled in the art.

To optimize the performance of the turbomachine, it is important that the trailing edges of the blades are as thin as possible.

However, the blade production methods currently used have limitations. Indeed, a trailing edge of a blade made from foundry cannot have a thickness less than about 0.3-0.4mm because the casting of metal in very thin spaces of a mold can present filling difficulties. and solidification. Furthermore, there is a compromise to be found between the thinnest possible thickness of a trailing edge and the life of the blade comprising this trailing edge, the thinner the trailing edge, the more fragile it is and susceptible to deformation.

The present invention provides a simple, effective and economical solution to at least some of these problems.

The invention thus proposes a blade for an aircraft turbine engine, this blade comprising a blade comprising a lower surface and an upper surface which are interconnected by a leading edge and by a trailing edge, the blade comprising a first portion connected to said first portion and made of a first material and defining said leading edge as well as parts of the lower and upper surfaces, and a second portion made of a second material, and defining said trailing edge as well as other parts of the intrados and of the extrados, characterized in that the said first portion extends over more than 75% of a chord of the blade.

In the present application, the term "chord" of a blade means the segment which connects the leading and trailing edges of the blade, in a plane perpendicular to an axis of elongation or a radial axis of the blade. The first portion extends over more than 75% of the chord of the blade and thus represents the largest portion of the blade.

It is thus understood that the two portions are manufactured independently of each other, which has several advantages. First of all, it is possible to make the portions in different materials. The manufacture of the second portion in a material different from the first portion can make it possible to reduce the thickness of the trailing edge by changing its material compared to the prior art.

It is also possible to make the portions by separate methods. In the event that these manufacturing methods would make it possible to produce thin thicknesses of material, it would also be possible to reduce the thickness of the trailing edge of the blade compared to the prior art.

The blade according to the invention may comprise one or more of the following characteristics, taken separately from each other or in combination with each other:

- the two portions are secured to each other by gluing, by additive manufacturing of one of the materials on the other of the materials, or are assembled by a male-female interlocking;

- the male-female interlock is configured to maintain the two portions in at least one direction;

- the blade is connected at opposite ends to two platforms;

- at least one retainer is attached to the blade in order to secure said first and second portions together;

- said at least one retainer is attached to the blade and/or at least one of the platforms;

- said at least one member is a pin engaged in orifices of the two portions;

- said at least one member is chosen from a spring, a nut, a rivet, a strip, and a clip;

- the first and second materials are metallic;

- the first and second materials are different, the second material being for example a ceramic and the first material being for example metallic.

The present invention also relates to a method for producing a blade as described above, in which it comprises the step of:

a) manufacture of said first portion, then

b) manufacture in situ of said second portion on said first portion or fixing of said second portion on said first portion.

Step b) can be carried out by male-female assembly of the two portions, and joining of the two portions by at least one attached retaining member.

In one embodiment of the invention, in step a), the two portions are made of metal by a method chosen from foundry, forging and additive manufacturing, optionally followed by machining, and, at 'step b), the first portion is heated and the second portion is cooled so that the portions are fixed together by shrinking.

In a variant embodiment of the invention, in which, in step a), the second portion is made of ceramic by a method chosen from among injection of ceramic into a mold, followed by firing, machining of a ceramic block, and a combination of the two.

Brief description of figures

The invention will be better understood and other details, characteristics and advantages of the invention will appear more clearly on reading the following description given by way of non-limiting example and with reference to the accompanying drawings in which:

FIG. 1 is a schematic perspective view of an aircraft turbine engine, seen from the downstream side and from the side,

Figure 2 is a schematic perspective view of a turbomachine rotor blade,

FIG. 3 is a schematic perspective view of turbomachine stator vanes,

FIG. 4 is a schematic perspective view of a portion of a blade according to one embodiment of the invention,

Figure 5 is a schematic perspective view of the portions of a blade according to the embodiment of Figure 4,

FIG. 6 is a schematic perspective view of portions of a blade according to a variant embodiment of the invention,

FIG. 7 is a schematic perspective view of a portion of the blade according to the variant embodiment of FIG. 6,

Figure 8 is a schematic perspective view of another portion of the blade according to the variant embodiment of Figure 6,

FIG. 9 is a very schematic view of an embodiment of a female portion of a blade,

FIG. 10 is a very schematic view of an embodiment of a female portion of a blade.

Detailed description of the invention

FIG. 1 schematically shows an aircraft turbomachine 10 which conventionally comprises a gas generator 12, one shaft of which drives a fan 14 which is here surrounded by a casing 15. The gas generator 12 comprises at least one compressor 16 , a combustion chamber 18 and at least one turbine 20.

In the case of a dual-flow turbomachine, respectively primary and secondary, the fan 14 generates an air flow which is divided into a primary flow which enters the gas generator 12 and into a secondary flow which flows around of the gas generator and is schematically represented by the arrows 22.

The primary flow notably passes through the compressor 16 and the turbine 18 which comprise blades.

Figure 2 shows a turbine rotor blade 24. Conventionally, the blade 24 comprises a blade 26, one end of which is connected to a root 28 and the opposite end of which is connected to a heel 30.

FIG. 3 represents a turbine nozzle sector 32, this sector comprising stator vanes 34 which extend between two platforms, respectively internal 36 and external 38. Each vane 34 is formed by a blade 26 which has a profile aerodynamic.

The present invention proposes a blade which may be a blade of a rotor or of a stator of an aircraft turbine engine.

As is the case with the blades described in the foregoing, the blade according to the invention comprises a blade 26 comprising an intrados and an extrados which are interconnected by a leading edge 26a and by a trailing edge 26b .

The blade 26 comprises a first portion P1 made from a first material and defining the leading edge 26a as well as parts of the lower surface and the upper surface, and a second portion P2 made from a second material and defining the leading edge. leak 26b as well as other parts of the intrados and the extrados.

In the present application, the term "chord" of a blade means the segment which connects the leading and trailing edges of the blade, in a plane perpendicular to an axis of elongation or a radial axis of the blade. The first portion P1 extends over more than 75% of the blade chord and therefore represents the largest portion of the blade.

Figures 4 and 5 illustrate a first embodiment of the invention in which the first portion P1 is made of metal alloy while the second portion P2 is made of ceramic.

The vane shown in the drawings is a nozzle vane 32 although this is not limiting.

The first portion P1 is a main portion of the blade 26 which has an axial extent measured along the longitudinal axis of the turbomachine, which represents between 60 and 95% of the maximum axial extent of the blade.

The second portion P2 is attached to the first portion P1 and can be held there by any appropriate technique. The second portion is for example partially engaged in a groove of the end of the first portion P1 intended to be covered by the second portion P2.

The second portion may have a radial extent measured relative to the longitudinal axis of the turbomachine, which is greater than that of the blade 26. The radially internal and external ends of this portion are then intended to be mounted or to pass through orifices provided for this purpose in the platforms 36, 38 of the distributor 32. The internal end of the second portion P2 is for example housed in a blind hole of the internal platform and its external end is for example engaged in an opening of the external platform (the blind hole and the opening are not shown in the drawings).

At least one retaining member can be attached to the blade 26 and/or to at least one of the platforms 36, 38, to ensure that the second portion P2 is held in place with respect to the first portion P1. This member 40 can be chosen from a spring, a nut, a rivet, a blade and a clip.

For example, a lamella could be welded to the outer platform 38, outside the vein extending between the platforms 36, 38, so as to hold the second portion P2 in place. The slat could pass over this second portion P2, with a slight twist to hold it firmly. In the event of repair, it would suffice to unbraze the slat to dismantle and replace the second portion P2.

Since ceramic is a refractory material, it withstands the temperature conditions encountered in a turbomachine very well. Furthermore, the trailing edge 26b is an area undergoing little or no impact, which limits the risk of the ceramic breaking.

In the event of degradation of portion P2 without degradation of portion P1, it is also possible to exchange it during maintenance, without having to change the entire blade or distributor 32.

Ceramic can be obtained in different ways, for example by a ceramic injection process in a mold, then firing. It can also be obtained by machining, or a combination of injection and machining. The thickness of the trailing edge 26b can then be reduced to 0.3 mm or even less depending on the qualities of the ceramic. The portion P2 can have a radial extent comprised between 5 and 10cm, and an axial extent comprised between 1 and 3cm. Its wall thickness can be of the order of 1mm on the side of the portion P1, and 0.2mm on the side of the trailing edge 26b.

Figures 6 to 8 illustrate another embodiment of the invention in which the two portions P1, P2 are made of metal alloy.

The two portions P1, P2 are assembled by a male-female fitting.

The male-female interlocking is configured to maintain the two portions in at least one direction and here in particular in a plane transverse to the blade perpendicular to the leading (not visible) and trailing edges 26b.

In the example shown, the second portion P2 comprises a male end 42 which has an elongated shape and is intended to be engaged in the female end 44 of complementary shape to the first portion P1 by sliding in a Y direction perpendicular to the aforementioned plane. . The male end 42 here has a substantially dovetail shape. Figures 9 and 10 illustrate variant embodiments of male-female interlocking.

At least one retainer 46 is attached to the blade and/or at least one of the platforms (not shown) of the corresponding blade to ensure that the two portions P1, P2 are held in place at least in the Y direction.

This member 46 can be a pin or a pin engaged in orifices 48 of the two portions P1, P2, as can be seen in the drawings. Advantageously, this pin is located outside the vein and therefore at the level of the platforms, that is to say that the blade 26 is intended to pass through an opening of this platform, as mentioned in the foregoing.

The dawn can be made in the following way.

Portions P1, P2 are manufactured independently of each other. The two portions are here made of metal by a method chosen from foundry, forging and additive manufacturing, possibly followed by machining. The first portion P1 is then heated and the second portion P2 is cooled so that these portions are fixed together by shrink fitting and male-female assembly. The retainer 48 is then attached to the portions P1, P2 to secure the assembly.

In general, the invention makes it possible to reduce and better control the thickness of a trailing edge of a turbine engine blade.

Claims (14)

Blade for an aircraft turbine engine, this blade comprising a blade (26) comprising an underside and an upper surface which are interconnected by a leading edge (26a) and by a trailing edge (26b), the blade comprising a first portion (P1) made of a first material and defining said leading edge as well as parts of the lower surface and the upper surface, and a second portion (P2) linked to said first portion and made of a second material, and defining said trailing edge as well as other parts of the lower surface and the upper surface, characterized in that said first portion extends over more than 75% of a chord of the blade. Blade according to claim 1, in which the two portions are secured to one another by gluing, by additive manufacturing of one of the materials on the other of the materials, or are assembled by a male-female fitting. Blade according to Claim 2, in which the male-female fitting is configured to ensure that the two portions (P1, P2) are held in place in at least one direction. Blade according to one of the preceding claims, in which the blade (26) is connected at opposite ends to two platforms (28, 30, 36, 38). Blade according to one of the preceding claims, in which at least one retaining member (46) is attached to the blade in order to secure said first and second portions together. Blade according to both of claims 4 and 5, in which said at least one retainer (46) is attached to the blade (26) and/or at least one of the platforms (28, 30, 36, 38). Blade according to Claim 5 or 6, in which the said at least one member (46) is a pin engaged in the orifices (48) of the two portions (P1, P2). Blade according to Claim 7, in which the said at least one member (40) is chosen from among a spring, a nut, a rivet, a strip and a clip. Blade according to one of the preceding claims, in which the first and second materials are metallic. Blade according to one of Claims 1 to 8, in which the first and second materials are different, the second material being for example a ceramic and the first material being for example metallic. Method of producing a blade according to one of the preceding claims, in which it comprises the step of:
a) manufacture of said first portion (P1), then
b) manufacture in situ of said second portion (P2) on said first portion or fixing of said second portion on said first portion. Method according to the preceding claim, in which step b) is carried out by male-female assembly of the two portions, and joining of the two portions by at least one attached retaining member (46). Method according to the preceding claim, in which, in step a), the two portions (P1, P2) are made of metal by a method chosen from foundry, forging and additive manufacturing, optionally followed by machining, and, in step b), the first portion is heated and the second portion is cooled so that the portions are secured together by shrink fit. Process according to Claim 12, in which, in step a), the second portion is made of ceramic by a method chosen from among injection of ceramic into a mold, followed by firing, machining of a ceramic block, and a combination of both.