The invention relates to a blade of a distributor of a turbomachine. In particular, the invention relates to a blade of a machine equipped with a blade of the cooling system and other parts of the turbomachine.

2. BACKGROUND

A turbine engine generally comprises, from upstream to downstream, one or more compressor stages, for example a low pressure compressor and a high pressure compressor, a combustor, one or more turbine stages, e.g., a high pressure turbine and a low pressure turbine. Upstream and downstream are defined with respect to the normal direction of flow of gas in a flow stream (from upstream to downstream).

The turbine converts thermal and kinetic energy of the flow of gas from the mechanical energy into combustion chamber necessary for example at the compressor drive and / or rotor in the case of a helicopter.

The turbine typically includes one or more stages of blades, each stage generally having, in known manner, a stationary blade array called distributor and a set of moving blades. All the blades of a grid of vanes is sometimes referred to as "blading". The blades comprise a portion facing upstream, said leading edge, and a portion directed downstream, said trailing edge.

The dispenser is generally cooled by forced convection by means of circuits browsing inside of the blades and forming a labyrinth. The cooling air enters the vanes on the side of the combustion chamber of the turbine at the periphery of the combustion chamber, at a portion of each blade dispenser called external meridian. The cooling air flows from the external meridian and passes through the vanes, so as to cool the blades of the interior (particularly the leading edges of the blades), to a portion of each vane called the inner meridian distributor , located on the side of a central hub of the

turbine. Cooling air or cold air terms mean air whose temperature is lower than the temperature of gas flowing in the flow passage of the turbomachine and to lower the temperature of the elements being in the flow passage.

A cooling air portion is imposed at these internal meridian to be transmitted to the hub, so as to cool other parts of the turbine. However, in the cooling systems where the blades are cooled to means labyrinth circuits, the air supplied to the hub is an air heated at the blade leading edges and therefore has a higher temperature than air cooling. In addition, the amount of consumed cooling air is important.

Other cooling systems incorporating inserts or double skins, arranged within the vanes, for cooling the inner surface of the blades. In particular, the inserts include a multi-perforated wall for cooling the leading edges of the vanes by cold air impacts. These inserts can reduce air consumption compared to labyrinth cooling systems. In addition, the convective heat transfer coefficients are higher than those induced by the system maze. In some cases, these inserts are extended so as to cross the internal meridian for feeding a portion of the bleed air to other parts of the turbine, via the hub.

However, this insert configuration causes a major leak of cold air at the interface between the insert and the internal meridian. The air passing through the leak is lost (including the flow passage of the gas) and is not used for cooling the blades or other parts of the turbine.

The inventors have sought a way to improve the blades of existing distributors.

3. Objectives of the invention

The invention aims to alleviate at least some of the disadvantages of known blades. In particular, the invention aims to provide, in at least one embodiment of the invention, a blade equipped with a cooling system that can effectively cool the blade and other parts of a turbomachine wherein East

installed dawn.

The invention also aims to provide, in at least one embodiment, a blade equipped with a cooling system whereby the cooling air consumption.

The invention also aims to provide, in at least one embodiment, a blade equipped with a cooling system that reduces the cooling air losses.

The invention also aims to provide, in at least one embodiment, a blade equipped with a cooling system to limit the heating of air passing through the vane to cool other parts of the turbomachine.

4. Summary of the Invention

To do this, the invention relates to a blade of a distributor of a turbomachine fitted with a cooling system comprising:

an insert arranged within an internal cavity of said vane, connected to a cooling air inlet of the blade and adapted to cool the surface of the internal cavity of the blade,

a removal device configured to remove a portion of the cooling air inside the insert and adapted to transmit to a central hub of the turbomachine,

characterized in that the sampling device comprises:

- a sampling head, disposed in the internal cavity of the blade and through an opening of the insert and configured to collect a portion of the cooling air within the insert.

A blade according to the invention therefore makes it possible, via the cooling system, a direct removal of a portion of the cooling air into the insert before it is heated by the elements to be cooled. The cooling air is therefore fed into the hub, centripetally, minimizing its heating between the inlet through the inlet of the blade and its arrival at the hub. therefore the temperature of the air arrived at the hub is close to the temperature of the inlet air of the insert. Once the portion of the cooling air fed to the hub, it is used to cool other elements of the turbomachine.

In addition, the provision of the pick-up head into the internal cavity of the blade helps to confine air leaks at the opening of the insert which is arranged in the picking head, which remain in the internal cavity of the blade. These air leaks are well controlled, they participate in the cooling vanes and air from leaking is not lost.

Advantageously and according to the invention, the sampling device comprises a sampling tube, connected firstly to the blade by a first ball joint and adapted to be connected secondly to a central hub of the turbomachine by a second ball joint, adapted to transmit the part of the air taken from the sampling head to the hub of the turbomachine.

According to this aspect of the invention, the ball joint type of mechanical linkages connecting the sampling tube to the blade and the hub allow the transmission of the portion of air sampled by the sampling head to the hub, while maintaining a possibility displacement between the blade distributor and the hub. These movements are due in particular to the action of thermomechanical loads, and can damage the sampling tube in the absence of these ball joints.

Advantageously and according to the latter aspect of the invention, the sampling head and the sampling tube are integrally connected.

According to this aspect of the invention, the sampling head and the sampling tube form a single piece, called sampling member, simple to manufacture without the need to change the blade significantly. In this variant of the invention, the clearance between the sampling head and the opening in the insert is designed to allow movement of the picking head, because the latter is integral with the sampling tube which may when moving the blade and / or the hub move, while minimizing air leakage at the opening.

Advantageously and according to the invention, the sampling head and the blade are integrally connected.

According to this aspect of the invention, the pick-up head is fixed, which reduces the clearance between the opening of the insert and the sampling head and thus reduce the air leakage at the opening. The sampling head may be formed from a portion of the vane and thus be made during manufacture of the blade.

The invention also relates to a dispenser comprising a plurality of blades arranged around a central hub of the turbomachine, characterized in that at least one vane of the dispenser is a blade according to the invention.

The invention also relates to a turbomachine, comprising a central hub and characterized in that it comprises a dispenser according to the invention.

The invention also relates to a blade, a distributor and a turbomachine characterized in combination by all or some of the features mentioned above or below.

5. List of Figures

Other objects, features and advantages of the invention will appear on reading the following description given by way of non-limiting and which refers to the appended figures in which:

Figure 1 is a schematic perspective view of a blade of a machine equipped with a cooling system according to a first embodiment of the invention,

Figure 2 is a schematic sectional view of a blade of a machine equipped with a cooling system according to a first embodiment of the invention,

Figure 3 is a schematic sectional view of a blade of a machine equipped with a cooling system according to a second embodiment of the invention.

6. Description of an embodiment of the invention

The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference is to the same embodiment, or that the specifications apply only to a single embodiment. Simple features of different embodiments may also be combined to provide other embodiments. In the figures, scales and proportions are not strictly complied with, for purposes of illustration and clarity.

Figures 1 to 3 show schematically, in perspective for FIG 1 and in section in Figures 2 and 3, a blade 10 of a distributor of a turbomachine. The blade 10, as disposed in a turbomachine, includes a portion called meridian 12 located outer side of a combustion chamber (not shown) of the turbomachine, and a portion called internal meridian 14 located on the side of a hub central 16 of the turbomachine around which parts of the turbomachine in rotation. In addition, the turbomachine being traversed from upstream to downstream by a gas, the portion of the blade 10 facing upstream is called edge 18 and the trailing portion of the blade 10 pointing downstream is called 20 trailing edge.

The blade 10 is equipped with a cooling system according to various embodiments described below. In Figures 1 to 3, arrows represent in part the flow of cooling air into the various elements of the blade 10 and / or cooling system.

The blade 10 shown in Figures 1 and 2 is equipped with a cooling system according to a first embodiment of the invention.

The cooling system comprises an insert 22, also called double skin disposed in an inner cavity 24 of the blade 10, and connected to an inlet 26 of cooling air from the blade 10. The insert comprises micro -perforations 28 to create cold air impacts on the surface of the internal cavity 24 of the blade 10, particularly at the edge 18 of attack.

The cooling system further comprises a sampling device comprising a hollow sampling head 30 disposed in the internal cavity 24 of the blade 10 and configured to collect a portion of the cooling air inside the insert 22. to do this, the sampling head 30 through an opening 34 of the insert 22 so that a portion of the air flowing in between the insert 22 in the head 30 of sample.

The interval between the opening 34 and the sampling head 30 causes leakage of cooling air 36. Since the sampling head 30 is disposed in the internal cavity 24 of the blade 10, air escaping through the leaks 36 remains in the internal cavity 24 of the blade 10 and therefore contributes to the cooling of the blade 10.

The sampling device further comprises a tube 32 of hollow sampling, adapted to transmit the portion of the bleed air within the insert 22 from the head 30 of the sampling and transmitted to the central hub 16.

Sampling tube 32 is connected at one end to the blade 10 by a first ball joint link 38 and secondly to the hub 16 by a second ball joint connection 40. In particular, the first ball bond 38 is located on the meridian 14 internal of the blade 10, because this part of the blade 10 is located near and opposite the hub 16. The links 38, 40 form joints mechanical connections allowing movement of the blade 10 and the hub 16 relative to each other.

In this first embodiment, the sampling head 30 and tube 32 of sample are integrally connected and form a single piece called sampling member.

Due to the presence of the first ball joint link 38 between the tube 32 for sampling and the blade 10, the sampling head 30 is movable in the opening 34 of the insert 22 in the event of displacement of the blade 10 relative to the hub 16. Thus, the dimensions of the opening 34 are adapted to this movement of the head 30 of sample: the clearance between the opening 34 and the head 30 of sample is large enough to allow movement of the head 30 of sample, but small enough to minimize leakage of air 36. As described above, these leaks 36 air are controlled in all cases and participate in the cooling of the blade 10, they do not represent cooling air losses.

The blade 10 shown in Figure 3 is equipped with a cooling system according to a second embodiment of the invention.

This embodiment is similar to the first embodiment described above, but the head 30 of sample is not integrally connected to the collection tube 32: the 30 sampling head is integrally connected to the blade 10, particularly at internal meridian 14 of the blade, facing the hub 16 of the turbomachine. The sampling head 30 may for example be formed of a part of

the blade 10 and the blade 10 manufactured with the same material.

CLAIMS

1. Paths to a distributor of a turbomachine fitted with a cooling system comprising:

- an insert (22) arranged inside a cavity (24) internal of said vane, connected to an input (26) of cooling air of the blade and adapted to cool the surface of the cavity (24 ) internal of the blade, a removal device configured to remove a portion of the cooling air inside the insert (22) and adapted to transmit to a hub (16) central of the turbomachine, characterized in that the sampling device comprises:

a head (30) for removing arranged in the cavity (24) internal of the blade and extending through an opening (34) of the insert and configured to collect a portion of the cooling air within the insert (22),

a tube (32) sampling, connected firstly to the blade by a first link (38) ball joint and adapted to be connected secondly to a hub (16) central of the turbomachine by a second link (40 ) ball, adapted to transmit the part of the air taken from the head (30) for taking to the hub (16) of the turbomachine.

2. A blade according to claim 1, characterized in that the head (30) and sampling tube (32) sampling are integrally connected.

3. A blade according to claim 1, characterized in that the head (30) for sampling and the blade are integrally connected.

4. Distributor of a turbomachine comprising a plurality of blades disposed around a hub (16) central of the turbomachine, characterized in that at least one of the dispenser blade is a blade (10) according to one of Claims 1 to 3.

5. A turbomachine, comprising a hub (16) central and characterized in that it comprises a distributor according to claim 4.