Module for an aircraft turbine engine

Abstract

The invention relates to a module (10) for an aircraft turbine engine (10), the module (10) comprising: - a rotor comprising an impeller (20) of a centrifugal compressor (12) and a wheel (22) of a turbine wheel (16), - a rectifier-diffuser (26) mounted at the impeller (20) outlet, - a turbine distributor (28) mounted upstream of the wheel (22), - an annular combustion chamber (14) interposed axially between the rectifier-diffuser (26) and the distributor (28), - an injector (56) of ventilation air surrounded by the combustion chamber (14), and - an arrangement of metal plates (32) connecting the rectifier-diffuser (26) to the distributor (28) and to the injector (56), said arrangement of metal plate (32) being configured to supply a flow of purge air to the turbine.

Description

[0001] DESCRIPTION

[0002] TITLE: MODULE FOR AN AIRCRAFT TURBOMACHINE

[0003] Technical field of the invention

[0004] The present invention relates to a module for an aircraft turbomachine, as well as a turbomachine comprising such a module.

[0005] Technical background

[0006] The state of the art includes in particular document FR-A-2 937 371, FR-A1 -2 904 038, FR-A1 -2 975 733, FR-A1 -2 904 034, FR-A1 -2 904 036, US-A1 -2021 / 199051, US-A1 -2008 / 141680, US-A1 -2022 / 243657 and US-A2-7,857,581.

[0007] An aircraft turbomachine includes a gas generator which classically comprises, from upstream to downstream, with reference to the flow of gases in the turbomachine, at least one compressor, one annular combustion chamber and at least one turbine.

[0008] In the case of a twin-spool turbofan engine, with low-pressure and high-pressure components respectively, the gas generator comprises, successively, a low-pressure compressor, a high-pressure compressor, the combustion chamber, a high-pressure turbine, and a low-pressure turbine. The gas generator defines a first annular flow path of gas, called the primary flow, which passes through the compressors, the combustion chamber, and the turbines.

[0009] The high-pressure compressor rotor is connected to the high-pressure turbine rotor by a high-pressure shaft. The low-pressure compressor rotor is connected to the low-pressure turbine rotor by a low-pressure shaft that passes through the high-pressure shaft and drives a propeller shaft, typically located upstream of the gas generator.

[0010] When this propeller is enclosed and thus surrounded by an annular casing, it is called a fan and generates an airflow, called a secondary flow, which flows around the gas generator. There are axial compressors and centrifugal compressors, and this application concerns a module and a turbomachine incorporating a centrifugal compressor. The distinguishing feature of the centrifugal compressor is that its rotor is formed by an impeller with an axially oriented inlet and a radially oriented outward outlet.

[0011] In a module or turbomachine, the impeller is connected to a turbine wheel by a shaft.

[0012] The combustion chamber is axially interposed between the centrifugal compressor and the turbine wheel and is supplied with air by a rectifier-diffuser mounted at the outlet of the wheel, which allows the air to be rectified before being diffused with an axial component.

[0013] During operation, the turbine wheel is subjected to significant thermal stresses and must be ventilated. It is therefore known that compressed air is drawn upstream of the chamber to ventilate the turbine wheel.

[0014] In particular, it is known to provide a ventilation air injector which is surrounded by the chamber and which includes an air outlet oriented axially downstream in order to ventilate the turbine wheel.

[0015] The applicant has already proposed solutions in the aforementioned documents for guiding the air exiting the compressor or the rectifier-diffuser within the annular space between the combustion chamber and the impeller shaft connecting to the turbine wheel, particularly to supply the injector. These solutions utilize a sheet metal arrangement that connects the rectifier-diffuser to the distributor and to the turbine wheel ventilation injector.

[0016] For example, in document FR-A1-2 904 036, Figure 4 shows a plate arrangement designed to guide a portion of the air exiting the rectifier-diffuser so that this air flows radially from the inside to the outside along a downstream radial face of the impeller. This air is then injected downstream of the chamber. The plate arrangement also guides another portion of the air exiting the rectifier-diffuser towards the turbine wheel ventilation injector.

[0017] However, it would also be desirable to find a solution for creating a purge airflow in the turbine, that is, an airflow intended to be injected into the turbine runner. The invention proposes an improvement to this technology that provides a simple, effective, and economical solution to this problem.

[0018] Summary of the invention

[0019] The invention relates to a module for an aircraft turbomachine, this module comprising:

[0020] - a rotor comprising a centrifugal compressor impeller and a turbine wheel, the impeller and the wheel being connected to each other by a shaft rotating around an axis,

[0021] - a stator comprising a rectifier-diffuser mounted at the outlet of the impeller and a turbine distributor mounted upstream of the moving wheel, the distributor and the moving wheel defining a gas flow path,

[0022] - an annular combustion chamber, also forming part of the stator and axially interposed between the rectifier-diffuser and the distributor, the combustion chamber comprising two coaxial annular walls, respectively internal and external, which are connected upstream by an annular chamber bottom, and

[0023] - a lamination arrangement connecting the rectifier-diffuser to the distributor and the injector, this lamination arrangement also forming part of the stator and comprising:

[0024] + a first annular sheet metal or portion of annular sheet metal which is surrounded by said internal wall of the chamber and which defines with this internal wall a first annular duct for the passage of air exiting the rectifier-diffuser, the air being intended to flow from upstream to downstream in this first duct,

[0025] + a second annular sheet metal or portion of annular sheet metal which surrounds said shaft and which, together with this shaft, defines a second annular air passage duct, this second duct being supplied with air by the first duct and the air being intended to flow from downstream to upstream in this second duct, and

[0026] + a third annular plate or portion of annular plate which is located downstream of the impeller and which extends radially from the inside to the outside from the second plate or portion of plate to the outlet of the impeller, this third plate or portion of plate defining with a downstream radial face of the impeller a third annular air passage duct which is supplied with air by the second duct, the air being intended to flow radially from the inside to the outside in this third duct, characterized in that the arrangement of plates is connected to the distributor by an annular flange, called the first flange, which comprises an annular row of axial air passage orifices in an axial direction, these axial orifices opening axially downstream into an annular space located between the first flange and the moving impeller and opening at its external periphery into said vein,and in that the sheet metal arrangement includes upstream at least one first opening for drawing ventilation air from the impeller in the third duct and downstream at least one second opening for supplying ventilation air to the impeller through the axial orifices.

[0027] The air exiting the rectifier-diffuser has been compressed in the centrifugal compressor and is at a relatively high pressure. Some of this air is guided by the lamination arrangement and flows radially from the inside to the outside along the downstream radial face of the impeller. This flow causes recompression of the air by vortex effect between the downstream radial face of the impeller and the lamination arrangement. Compressed air at a pressure higher than that exiting the rectifier-diffuser is therefore found at the impeller outlet. According to the invention, the lamination arrangement is designed to convey this air to the turbine, where it is then injected into the turbine runner to create a blowdown flow. To this end, the lamination arrangement includes openings for drawing in and supplying this drawn air.It is a flange attached to the distributor that includes an annular row of orifices allowing the air to pass to the turbine runner. This compressed air is at a higher pressure than the air exiting the rectifier-diffuser, which is particularly advantageous as it improves the efficiency of the purge. Although the temperature of the compressed air exiting the rectifier-diffuser can also increase due to viscous friction with the impeller as the air flows along its downstream radial face, the compressed air will have time to return to its initial temperature (at the rectifier-diffuser outlet) before reaching the injector because it passes through the lamination arrangement, which is generally at the same temperature as the air exiting the rectifier-diffuser. The lamination arrangement can consist of one or more laminations or one or more sections of lamination.

[0028] The module according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0029] -- said module further includes at least one ventilation air injector also forming part of the stator, said injector being surrounded by the combustion chamber and being configured to inject ventilation air towards the moving wheel;

[0030] -- the arrangement of sheet metal connects the rectifier-diffuser to the distributor and the injector;

[0031] - said at least a first opening is formed by an annular row of orifices which is located radially at the level of the external periphery of the wheel;

[0032] - the arrangement of sheets forms an internal annular cavity which is radially interposed between the shaft and the combustion chamber and which includes an air inlet formed by said at least a first opening, and an air outlet formed by said at least a second opening;

[0033] -- said at least one injector is oriented in a radial direction and is configured to deliver an airflow in a radial direction;

[0034] -- a labyrinth-type seal is mounted upstream of a radially internal periphery of the injector, and another labyrinth-type seal is mounted downstream of the radially internal periphery of the injector;

[0035] - the sheet metal arrangement includes a flange, particularly downstream, and the first flange includes a flange, particularly upstream, the flange of the sheet metal arrangement being fixed to the flange of the first;

[0036] -- the injector has a radially external periphery which is axially interposed between the flange of the sheet metal arrangement and the flange of the first flange;

[0037] - said at least a second opening extends axially between the flange of the sheet metal arrangement and the flange of the first flange; - said at least a second opening passes axially through the flange of the sheet metal arrangement;

[0038] -- said at least one second opening traverses axially a radially external periphery of the injector, or even traverses

[0039] -- said at least one second opening crosses axially the flange of the first flange or crosses axially the hollowed parts of the flange of the first flange;

[0040] - said at least a second opening is formed by an annular row of holes formed in the flange of the sheet metal arrangement circumferentially next to mounting holes for fixing screws of this flange, the number of holes in the second opening being equal to the number of mounting holes for the screws and each of the holes in the second opening having a diameter representing less than one third of a diameter of the mounting holes for the screws;

[0041] - the flange of the sheet metal arrangement includes radially oriented lunules or openings for the fluidic communication of said first conduit with said second conduit;

[0042] - the flange of the first flange is located at the radially internal periphery of an upstream annular wall of the first flange, and the orifices of the first flange are located on a downstream annular wall of the first flange which is connected by its external periphery to the upstream wall of the first flange;

[0043] - the downstream annular wall of the first flange has a radially internal periphery connected to a seal support(s), the seal support(s) carrying at least one abradable ring intended to cooperate with rotor wipers;

[0044] -- the downstream annular wall of the first flange has a radially internal periphery which is in radial support on a part of the internal periphery of the injector;

[0045] - the orifices of the first flange are located axially opposite a second annular flange which is mounted on the moving wheel, upstream of the moving wheel;

[0046] - the second flange is fixed to said shaft and bears axially on the outer periphery of a disc of the moving wheel; - the second flange carries external annular scrapers mounted opposite an abradable ring mounted on the stator so as to form a sealing gasket;

[0047] -- the slats of the second flange are configured to cooperate with the abradable ring of the first flange, and in particular with the sealing gasket support of this first flange;

[0048] - the second flange includes an annular row of radial air passages, allowing ventilation air to pass between the second flange and the moving wheel, and more particularly between the second flange and the wheel disc;

[0049] -- said air passage orifices are radially aligned with the injector; The present invention also relates to an aircraft turbomachine, comprising at least one module as described above.

[0050] Brief description of the figures

[0051] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the attached drawings in which:

[0052] [Fig.1] Figure 1 is a schematic half-view in axial cross-section of a module according to the invention for an aircraft turbomachine,

[0053] [Fig. 2] Figure 2 is a larger-scale view of part of Figure 1.

[0054] [Fig. 3] Figure 3 is another larger-scale view of part of Figure 1, and

[0055] [Fig.4] Figure 4 is a partial schematic view of a module clamping according to the invention.

[0056] Detailed description of the invention

[0057] Figure 1 shows a module 10 for an aircraft turbomachine, this turbomachine being here a twin-spool turbojet although this example is not limiting.

[0058] Axis A designates the longitudinal axis of the turbomachine.

[0059] The turbomachine is partially represented and includes a gas generator which comprises, from upstream to downstream with reference to the flow of gases along axis A, at least one compressor 12, an annular combustion chamber 14 and at least one turbine 16.

[0060] The turbomachine may include a low-pressure compressor (not shown) followed by a high-pressure centrifugal compressor (shown), and the turbine may also include a high-pressure turbine (shown) followed by a low-pressure turbine (not shown).

[0061] The compressor rotor (centrifugal) 12 is connected to the turbine rotor (high pressure) 16 by a shaft (high pressure) 18. The shaft 18 is movable around the axis A.

[0062] The compressor rotor 12 is formed by a wheel 20. The turbine rotor 16 is formed by a wheel 22. The shaft 18 connects the wheel 20 and the wheel 22 and forms with them a rotor or rotating body, in particular high pressure.

[0063] The combustion chamber 14 comprises two coaxial annular walls, respectively internal 14a and external 14b, which are connected upstream by an annular chamber bottom 14c.

[0064] As is known, the bottom of chamber 14c is equipped with fuel injection systems 24 into the combustion chamber 14.

[0065] Module 10 includes several other stator elements, notably a rectifier-diffuser 26 and a distributor 28 for the turbine 16. The rectifier-diffuser 26 is mounted at the output of the impeller 20 and comprises a first annular portion forming a rectifier 26a and a second annular portion forming a diffuser 26b. The first portion is oriented radially, and the second portion is oriented towards the chamber 14 with an axial component. This type of rectifier-diffuser 26 is known.

[0066] The distributor 28 is a bladed distributor, that is to say, it comprises an annular row of blades 28a. It is axially interposed between the outlet of chamber 14 and wheel 22.

[0067] The wheel 22 also includes an annular row of blades 22a which are mounted on the periphery of a disk 22b. The blades 22a include feet which are mounted axially in recesses on the outer periphery of the disk 22b in a known manner.

[0068] The wheel 22 is surrounded by a sealing ring 30 which, together with platforms 22c of the blades 22a, defines a first portion of the turbine stream V. The blades 28a of the distributor 28 extend between two annular ferrules 28b, 28c of the distributor 28 which delimit between themselves a second portion of the turbine stream V, located upstream of the first portion mentioned above and directly at the exit of the chamber 14.

[0069] The distributor 28 further includes a foot 28d which extends radially inwards from the inner ferrule 28b.

[0070] The stator further comprises a lamination arrangement 32 which provides the connection between the rectifier-diffuser 26 and the distributor 28, and more particularly between the rectifier-diffuser 26 and a first annular flange 34 integral with the distributor 28. In the example shown, the first flange 34 comprises an outer periphery 34a fixed to the inner periphery of the distributor 28 and in particular to its base 28d, and an inner periphery 34b fixed to the lamination arrangement 32. Preferably, the inner periphery 34b of the flange 34 comprises an annular flange 35 for fixing to the lamination arrangement 32. Preferably, the inner periphery 34b of the flange 34 forms or is connected to a support for seal(s).

[0071] A second annular flange 36 can be fixed to the wheel 22. The flange 36 comprises an outer periphery 36a bearing axially on the outer periphery of the disc 22b, for the purpose of retaining the blades (by axial bearing of their feet on the flange 36) on the disc 22b, and an inner periphery 36b fixed to the shaft 18. In particular, in the example shown, the inner periphery 36b is axially interposed between a portion of shaft 18a, located upstream and integral with the wheel 20 and another portion of shaft 18b, located downstream and integral with the disc 22b.

[0072] At least one annular sealing gasket 38 is preferably mounted between the second flange 36 and the first flange 34. The gasket 38 is preferably labyrinth-type and includes annular rotor wipers 38a carried by or formed on the second flange 36 and adapted to cooperate by friction with at least one abradable ring 38b carried by the first flange 34. Preferably, the gasket 38 is located radially inside the flange 35 and thus surrounded by this flange 35.

[0073] In the context of the present invention, the flange 34 comprises an annular row of air passage orifices 34d f7 in an axial direction. These orifices 34d open axially downstream into an annular space E which is located between the flange 34 and the wheel 22 and which opens at its outer periphery into the vein V.

[0074] The flange 35 of the first flange 34 is located on the inner periphery of an upstream annular wall 34x of the first flange 34. The orifices 34d of the first flange 34d are located on a downstream annular wall 34y of the first flange 34. This downstream wall 34y is here connected by its outer periphery to the upstream wall 34x of the first flange 34.

[0075] The downstream wall 34y may have its internal periphery which is in radial support on a part of the internal periphery of an injector 56.

[0076] The orifices 34d are located axially opposite the second flange 36.

[0077] The arrangement of sheet metal 32 is both axially intercalated between the wheel 20 and the distributor 28, or here the flanges 34, 36, and radially between the shaft 18 and the combustion chamber 14.

[0078] As its name indicates, the arrangement of sheets 32 is formed by sheets or portions of sheets which allow in particular to guide part of the air exiting the rectifier-diffuser 26, and in particular the part of the air which bypasses the chamber 14 radially from the inside.

[0079] Figures 1 and 2 show the air F1 exiting the centrifugal compressor 12 and supplying the rectifier-diffuser 26, as well as the air F2 exiting the rectifier-diffuser. Part of this air F2 bypasses the chamber 14 internally and is designated as f2. The remainder of this air enters the chamber 14 or bypasses the chamber 14 radially externally.

[0080] The arrangement of sheets 32 includes a first annular sheet 32a or portion of annular sheet which is surrounded by the internal wall 14a of the chamber 14 and which defines with this internal wall 14a a first annular conduit 40 for the passage of air f1, this air f1 being intended to flow from upstream to downstream in this first conduit 40.

[0081] The sheet metal 32a extends for example from the inner periphery of the rectifier-diffuser 26 to an annular flange 42 for fixing to the flange 35 of the first flange 34.

[0082] In the example shown, the sheet metal 32a essentially comprises two portions: an upstream portion 32a1, which is cylindrical, and a downstream portion 32a2, which is frustoconical and converges downstream. The upstream end of the upstream portion 32a1 is connected to the inner periphery of the rectifier-diffuser 26, and its downstream end is located inside the inner wall 14a of the chamber 14 and is connected to the upstream end of the second portion 32a2. This second portion 32a2 is substantially parallel to the wall 14a of the chamber, and its inner periphery is connected to the flange 42.

[0083] The flange 42 includes axial ports aligned with ports in the flange 35 for the passage of fasteners 44, such as screw-nuts. Unlike prior art solutions, these flanges 42 and 35 do not have axial air passage ports.

[0084] In the example shown, however, the flange 42 includes lunules 46 or radially oriented lights for the passage of air in a radial direction in particular from the downstream end of the first conduit 40 (arrow f2 in figures 1 and 3).

[0085] The arrangement of the plates 32 includes a second annular plate 32b, or portion of annular plate, which surrounds the shaft 18, and in particular the portion of shaft 18a, and which, together with this shaft 18, defines a second annular air passage 48. This second passage 48 is supplied with air by the first passage 40, in particular through the lunules 46, and the air f3 is intended to flow from downstream to upstream in this second passage 48.

[0086] Sheet metal 32b extends upstream from flange 42 of sheet metal 32a.

[0087] In the example shown, the sheet metal 32b essentially comprises two portions: a first downstream portion 32b1, which is frustoconical and converges upstream, and a second upstream portion 32b2, which is cylindrical. The first portion 32b1 has a downstream end connected to the flange 42 and an upstream end connected to the downstream end of the second portion 32b2. This second portion 32b2 is preferably located at a short radial distance from the shaft 18 so that the conduit 48 has the smallest possible diameter.

[0088] The first portion 32b1 can be located axially opposite the second flange 36, in particular a radial wall 36c of the second flange 36 which extends between the shaft 18 and the first flange 34. The first portion 32b1 can be located radially inside the second portion 32a2 and can therefore be surrounded by this portion 32a2 as in the example shown.

[0089] The second portion 32b2 can be located radially inside the first portion 32a1.

[0090] The arrangement of plates 32 includes a third annular plate 32c or portion of annular plate which is located (preferably just) downstream of the wheel 20 and which extends radially from the inside out from the second plate 32b to the exit of the wheel 20.

[0091] This third sheet metal 32c defines with a downstream radial face 20a of the wheel 20 a third annular air passage 50 f4 which is supplied with air by the second conduit 48. The air f4 is intended to flow radially from the inside to the outside in this third conduit 50 and to be recompressed by vortex effect due to its passage near the face 20a of the wheel 20.

[0092] Sheet metal 32c extends, for example, from the upstream end of sheet metal 32b to the inner periphery of the rectifier-diffuser 26. Sheet metal 32a and 32c can be connected to the rectifier-diffuser 26 in the same area as in the example shown.

[0093] In the example shown, the sheet metal 32c essentially comprises two portions: a first downstream portion 32c1, which is frustoconical and flared upstream, and a second upstream portion 32c2, which is radial and extends outwards. The first portion 32c1 has a downstream end or inner periphery connected to the upstream end of the sheet metal 32b, and in particular to its portion 32b2, and an upstream end or outer periphery connected to the radially inner end of the second portion 32c2. This second portion 32c2 is connected to the rectifier-diffuser 26, specifically to the upstream end of the sheet metal 32a.

[0094] The sheet metal 32c can be located radially inside the sheet metal 32a, and therefore be surrounded by the sheet metal 32a. In particular, the portions 32c1, 32c2 can be surrounded by the first portion 32a1 of the sheet metal 32a.

[0095] The first portion 32c1 can be located axially opposite portion 32b1. The second portion 32c2 can be located axially opposite portion 32a2 and / or flange 42. In the example shown, it can be seen that the arrangement of sheets 32 internally delimits an internal annular cavity 54. This cavity 54 is delimited externally by sheet 32a, internally by sheet 32, upstream by sheet 32c, and downstream by portions 32a2 and 32b1 of sheets 32a, 32b.

[0096] The arrangement of sheets 32 may include annular stiffening ribs 52. In the example shown, this is the case for sheet 32 ​​and in particular its second portion 32b2. The ribs 52 are located radially inside the internal cavity 54 of the arrangement of sheets 32.

[0097] Module 10 may further include at least one air injector 56 which allows the turbine wheel 22 to be ventilated.

[0098] This injector 56 allows ventilation air to be injected at the turbine wheel 22b and in particular at its disc 22b. The injector 56 thus has at least one air outlet 56b directed towards the distributor 28.

[0099] In the drawings, it can be seen that the injector 56 has a radial orientation and comprises an inner periphery forming an air inlet and an outer periphery forming an air outlet f8. The injector 56 is thus capable of supplying an airflow f8 oriented radially with respect to the axis, here inwards through an annular row of orifices 58 in the second flange 36. These orifices are radially aligned with the injector 56 for the passage of ventilation air through these orifices 58 between the second flange 36 and the wheel 22. The injector 56 is preferably axially interposed between the flanges 42 and 35. In the example shown, the outer periphery of the injector 56 is axially interposed between the flanges 42 and 35.

[0100] Figure 1 shows that a first sealing gasket is located upstream of these orifices 58 and is formed by external flanges 38a carried by or formed on the second flange 36 and adapted to cooperate with a first abradable element 38b, and a second sealing gasket is located downstream of these orifices 58 and is formed by external flanges 38a carried by or formed on the second flange 36 and adapted to cooperate with a second abradable element 38b. There are therefore two labyrinth seals located axially on either side of the orifices 58.

[0101] The air outlet f8 passes between these two sealing joints. According to the invention, the arrangement of sheets 32 includes openings 64, 66 for the extraction of air f5 from the third duct 50 and the supply of the orifices 34d with this extracted air f6, f7.

[0102] Preferably, the arrangement of sheets 32 includes at least a first opening 64 upstream for the extraction of air f5 in the third conduit 50, and at least a second opening 66 downstream for supplying the orifices 34d with this extracted air f6, f7.

[0103] As in the example shown, the first opening 64 can be formed by an annular row of orifices which is located at the level of the external periphery of the wheel 20, and the second opening 66 is formed by another annular row of orifices which is preferably formed in the flange 42.

[0104] Advantageously, the first opening 64 or its orifices form(s) an air inlet into the internal cavity 54, and the second opening 66 or its orifices form(s) an air outlet from this cavity 54.

[0105] In the example shown, the first opening 64 (or its orifices) is formed in the portion 32c2 of the sheet 32c, closest to the outer periphery of this sheet 32c.

[0106] Advantageously, the second opening 66 (or its orifices) extends axially through the flange 42 of the sheet metal arrangement 32.

[0107] The second opening 66 extends axially preferably through an external periphery of the injector 56, or even through the flange 35 of the first flange 34 or hollowed parts of the flange 35 of the first flange 35 in particular when this flange 35 is of the scalloped type (figure 3).

[0108] The second opening 66 is preferably formed by an annular row of orifices 66a formed in the flange 42 of the sheet metal arrangement 32 next to mounting orifices 44a for fixing screws 44 of this flange 42.

[0109] The number of orifices 66a can be equal to the number of orifices 44a and each of the orifices 66a can have a diameter D2 representing less than one third of a diameter D1 of the orifices 44a (figure 4).

[0110] It is therefore understood that the air circulates in module 10 as follows. Air F1 exits the centrifugal compressor 12 at a given pressure and flows into the rectifier-diffuser 26, which diffuses air F2. Part of this air F1 bypasses the chamber 14 internally and flows through the conduit 40 and passes through the lunules 46. Air F2, F3 then flows through the conduit 48 to the conduit 50. When air F4 rises along the downstream face 20a of the impeller 20, it is further compressed by vortex effect and has a pressure higher than that at the outlet of the impeller 20. This air F5 passes through the opening 64, enters the cavity 54, and then exits through the opening 66 to supply the orifices 34d with air F6, F7. This air f7 circulates radially from the inside to the outside in space E to join the vein V by passing between the ferrule 28b of the distributor 28 and the platform 22c of the wheel 22 (arrow f9).

[0111] Although the temperature of the air f4 may also increase by viscous friction with the wheel 20, this air will have time to return to a temperature close to or identical to the air F2 or f1 due to the passage of the air f5 through the arrangement of sheets 32 which is globally at the temperature of the air F2, f1.

[0112] Although not shown, fins could be present on the radial face 20a of the wheel in order to accentuate the air recompression phenomenon f4.

[0113] In general, the invention improves the efficiency of the purging process. Furthermore, it allows the distributor to be supplied with air at a higher pressure and at a constant temperature. This enables it to be cooled with greater pressure and therefore a higher flow rate while maintaining the temperature without compression, thus improving the distributor's cooling.

Claims

DEMANDS 1. Module (10) for an aircraft turbomachine, this module (10) comprising: - a rotor comprising a centrifugal compressor impeller (20) (12) and a turbine impeller (22) (16), the impeller (20) and the turbine impeller (22) being connected to each other by a shaft (18) that rotates about an axis (A), - a stator comprising a rectifier-diffuser (26) mounted at the outlet of the impeller (20) and a turbine distributor (28) mounted upstream of the rotating wheel (22), the distributor (28) and the rotating wheel (22) defining a gas flow path (V), - an annular combustion chamber (14) also forming part of the stator and axially interposed between the rectifier-diffuser (26) and the distributor (28), the combustion chamber (14) comprising two coaxial annular walls, respectively internal (14a) and external (14b), which are connected upstream by an annular chamber bottom (14c), - a lamination arrangement (32) connecting the rectifier-diffuser (26) to the distributor (28), this lamination arrangement (32) also forming part of the stator and comprising: + a first annular sheet (32a) or portion of annular sheet which is surrounded by said internal wall (14a) of the chamber (14) and which defines with this internal wall (14a) a first annular duct (40) for the passage of air (f1) exiting the rectifier-diffuser (26), the air (f1) being intended to flow from upstream to downstream in this first duct (40), + a second annular sheet (32b) or portion of annular sheet which surrounds said shaft (18) and which defines with this shaft (18) a second annular air passage duct (48), this second duct (48) being supplied with air by the first duct (40) and the air (f3) being intended to flow from downstream to upstream in this second duct (48), and + a third annular plate (32c) or portion of annular plate which is located downstream of the impeller (20) and which extends radially from the inside to the outside from the second plate (32b) or portion of plate to the outlet of the impeller (20), this third plate (32c) or portion of plate defining with a downstream radial face (20a) of the impeller (20) a third annular air passage duct (50) which is supplied with air by the second duct (48), the air (f4) being intended to flow radially from the inside to the outside in this third duct (50), characterized in that the plate arrangement (32) is connected to the distributor (28) by an annular flange (34), called the first flange, which comprises an annular row of axial air passages (34d) (f7) in an axial direction, these axial passages (34d) opening axially downstream into an annular space (E) located between the first flange (34) and the impeller (22) and opening at its outer periphery into said channel (V), and in that the plate arrangement (32) comprises upstream at least a first opening (64) for drawing ventilation air (f5) from the impeller (22) into the third duct (50) and downstream at least one second opening (66) for supplying ventilation air to the moving wheel (22) through the axial orifices (34d).

2. Module (10) according to claim 1, wherein said at least a first opening (64) is formed by an annular row of orifices which is located radially at the level of the external periphery of the wheel (20).

3. Module (10) according to claim 1 or 2, wherein the arrangement of sheets (32) forms an internal annular cavity (54) which is radially interposed between the shaft (18) and the combustion chamber (14) and which includes an air inlet formed by said at least a first opening (64), and an air outlet formed by said at least a second opening (66).

4. Module (30) according to any one of the preceding claims, wherein the arrangement of sheets (32) comprises a flange (42) and the first flange comprises a flange (35), the flange (42) of the arrangement of sheets (32) being fixed to the flange (35) of the first flange (34).

5. Module (10) according to claim 4, wherein said at least one second opening (66) extends axially between the flange (42) of the sheet metal arrangement and the flange (35) and of the first flange (34).

6. Module (10) according to claim 4 or 5, wherein said at least one second opening (66) passes axially through the flange (42) of the sheet metal arrangement (32).

7. Module (10) according to claim 6, wherein said at least one second opening (66) passes axially through the flange (35) of the first flange (34) or axially traverses hollowed parts of the flange (35) of the first flange (34).

8. Module (10) according to claim 6 or 7, wherein said at least one second opening (66) is formed by an annular row of holes (66a) formed in the flange (42) of the sheet metal arrangement (32) circumferentially next to holes (44a) for mounting screws (44) for fixing this flange (42), the number of holes (66a) of the second opening (66) being equal to the number of holes (44a) for mounting the screws (44) and each of the holes (66a) of the second opening (66) having a diameter (D2) representing less than one third of a diameter (D1) of the holes (44a) for mounting the screws (44).

9. Module (10) according to any one of claims 7 to 8, wherein the flange (42) of the sheet metal arrangement (32) comprises radially oriented lunules (46) or openings for the fluidic communication of said first conduit (40) with said second conduit (48).

10. Module (10) according to any one of claims 4 to 9, wherein the flange (35) of the first flange (34) is located at the radially internal periphery of an upstream annular wall (34x) of the first flange (34), and the orifices (34d) of the first flange (34) are located on a downstream annular wall (34y) of the first flange (34) which is connected by its external periphery to the upstream wall (34x) of the first flange (34).

11. Module (10) according to the preceding claim, wherein the downstream annular wall (34y) of the first flange (34) has a radially internal periphery connected to a seal support(s), the seal support(s) carrying at least one abradable ring (38b) intended to cooperate with rotor blades (38a).

12. Module (10) according to any one of the preceding claims, wherein the orifices (34d) of the first flange (34) are located axially opposite a second annular flange (36) which is mounted on the movable wheel (22), upstream of the movable wheel (22).

13. Module (10) according to the preceding claim, in which the second flange (36) is fixed to said shaft (18) and bears axially on the outer periphery of a disc (22b) of the movable wheel (22).

14. Module (10) according to claim 12 or 13, wherein the second flange (36) carries external annular strips (38a) mounted opposite an abradable ring (38b) mounted on the stator so as to form a sealing gasket (38).

15. Module (10) according to any one of claims 12 to 14, wherein the second flange (36) comprises an annular row of radial air passage orifices (58) to allow ventilation air to pass between the second flange (36) and the movable wheel (22) 16. Turbomachine for an aircraft, comprising at least one module (10) according to one of the preceding claims.

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