MODULE FOR AN AIRCRAFT TURBOMACHINE

Abstract

Module (10) for an aircraft turbomachine, this module (10) comprising: - a rotor including a centrifugal compressor wheel (20) (12) and a turbine wheel (22) (16), the wheel (20) and the wheel (22) being connected to each other by a shaft (18) movable about an axis (A), - a stator including a rectifier-diffuser (26) mounted at the outlet of the wheel (20) and a turbine distributor (28) mounted upstream of the wheel (22), - an annular combustion chamber (14) also forming part of the stator and axially interposed between the rectifier-diffuser (26) and the distributor (28), and - a lamination arrangement (32) connecting the rectifier-diffuser (26) to the distributor (28), this lamination arrangement (32) also forming part of the stator and defining an annular cavity (54) which extends around and at a distance from said tree (18) and is surrounded at a distance by the chamber (14). Figure for the abbreviation: Figure 1

Description

Title of the invention: MODULE FOR AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to a module for an aircraft turbomachine, as well as a turbomachine comprising such a module. Technical background

[0002] 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 and FR-A1-2 904 036.

[0003] An aircraft turbomachine includes a gas generator which conventionally comprises, from upstream to downstream, with reference to the flow of gases in the turbomachine, at least one compressor, an annular combustion chamber and at least one turbine.

[0004] 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.

[0005] The rotor of the high-pressure compressor is connected to the rotor of the high-pressure turbine by a high-pressure shaft. The rotor of the low-pressure compressor is connected to the rotor of the low-pressure turbine by a low-pressure shaft which passes through the high-pressure shaft and drives a shaft of a propulsion propeller generally located upstream of the gas generator.

[0006] When this propeller is enclosed and therefore surrounded by an annular casing, this propeller is called a blower and generates an airflow, called a secondary flow, which flows around the gas generator.

[0007] Axial compressors and centrifugal compressors exist, and the present application relates to a module and a turbomachine comprising a centrifugal compressor. The distinctive feature of the centrifugal compressor is that its rotor is formed by an impeller which includes an axially oriented inlet and an outwardly radially oriented outlet.

[0008] In a module or turbomachine, the impeller is connected to a turbine wheel by a shaft.

[0009] The combustion chamber is axially interposed between the centrifugal compressor and the turbine wheel and is supplied with air by an outlet-mounted rectifier-diffuser of the spinning wheel and which allows the air to be straightened before being diffused with an axial component.

[0010] The combustion chamber comprises two coaxial annular walls, respectively inner and outer, which are connected upstream by an annular chamber floor. This chamber floor carries an annular row of fuel injection systems inside the chamber.

[0011] The applicant has already proposed in the aforementioned documents solutions for guiding the air exiting the compressor or the rectifier-diffuser in the annular space contained between the combustion chamber and the connecting shaft of the impeller to the turbine wheel.

[0012] One problem arises from the fact that this annular space is relatively large and is likely to increase in pressure with engine speed. During a decrease in engine speed, the main turbomachine flow may then have a lower pressure than that in this space. The direct consequence is that this pressurized space empties into the flow and risks causing engine surge.

[0013] The aforementioned solutions thus employ an arrangement of sheets which connects the rectifier-diffuser to the distributor and which allows the annular space to be occupied in order to avoid this pumping phenomenon.

[0014] The invention proposes an improvement to this technology, which is simple, efficient and economical. Summary of the invention

[0015] The invention relates to a module for an aircraft turbomachine, this module comprising:

[0016] - a rotor comprising a centrifugal compressor wheel and a turbine wheel, the The spinning wheel and the wheel are connected to each other by a shaft that rotates around an axis.

[0017] - a stator comprising a rectifier-diffuser mounted at the output of the wheel and a turbine distributor mounted upstream of the wheel,

[0018] - an annular combustion chamber also forming part of the stator and axially interposed between the rectifier-diffuser and the distributor, the combustion chamber comprises two coaxial annular walls, respectively internal and external, which are connected upstream by an annular chamber bottom, and

[0019] - an arrangement of connecting plates from the rectifier-diffuser to the distributor, this arrangement of sheet metal also forming part of the stator and defining an annular cavity which extends around and at a distance from said shaft and is surrounded at a distance by the chamber,

[0020] characterized in that the arrangement of sheets comprises a first annular sheet which defines an internal periphery of said cavity and which comprises an upstream end comprising an external cylindrical shrink-fit surface on a part of the sheet metal arrangement, and a downstream end which includes an internal cylindrical surface capable of sliding axially on another part of the sheet metal arrangement or an element connected to this sheet metal arrangement.

[0021] The sheet metal that defines the internal periphery of the cavity is thus designed and mounted to compensate for differential thermal expansions and global movements of the motor in operation.

[0022] The module according to the invention may comprise one or more of the following features, taken individually or in combination with each other: - the upstream end of the first sheet includes a cylindrical rim oriented towards the wheel and comprising said shrink-fitting surface; - the upstream end of the first sheet includes an annular rib which extends radially outwards from said shrink-fitting surface; - the downstream end of the first sheet includes a cylindrical rim oriented downstream and comprising said internal cylindrical surface; - the downstream end of the first sheet includes an annular rib which extends radially outwards from said cylindrical rim; - the cylindrical rim includes at its upstream end of connection to the rest of the first sheet an annular groove opening radially inwards; - an annular weld bead is deposited in the groove and at the connection with the rest of the first sheet, this weld bead defining an annular surface which is perpendicular to said axis and downstream in order to form an axial support for said element; - said internal cylindrical surface has an axial dimension greater than that of said shrink-fitting surface, or at least twice greater than that of said shrink-fitting surface;

[0023] — said internal cylindrical surface has a diameter which is equal to the diameter of said shrink-fitting surface, to within + / -10%; - the first sheet comprises an upstream frustoconical section converging downstream and having its end of largest diameter connected to said upstream end; - the first sheet comprises a truncated conical downstream section converging upstream and having its end of largest diameter connected to said downstream end; - the first sheet includes an intermediate cylindrical section extending between the smaller diameter ends of the upstream and downstream sections; - the first sheet includes external annular stiffening ribs and / or at least one annular row of air passage holes; - the ribs are located on the intermediate section and / or said at least one row of orifices is located on the downstream section; - the upstream end of the first sheet is shrink-fitted to a radially internal end of a second annular sheet fixed to the rectifier-diffuser, and the downstream end of the first sheet is radially supported on an external cylindrical surface of a ventilation air injector, this ventilation injector being fixed to a downstream end of a third annular sheet which defines an external periphery of the cavity and whose upstream end is fixed to the rectifier-diffuser;

[0024] — the chamber bottom carries an annular row of injection systems fuel inside the chamber.

[0025] The present invention also relates to an aircraft turbomachine, comprising at least one module as described above. Brief description of the figures

[0026] 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 accompanying drawings in which:

[0027] [Fig-1] [Fig.1] is a schematic half-view in axial section of a module according the invention for an aircraft turbomachine,

[0028] [Fig.2] [Fig.2] is a schematic cross-sectional and perspective view of part of the module of [Fig.1];

[0029] [Fig.3] [Fig.3] is a larger scale view of part of [Fig.1], and shows an annular sheet;

[0030] [Fig.4] [Fig.4] is another larger scale view of an upstream end of the annular sheet of [Fig.3];

[0031] [Fig. 5] [Fig. 5] is another larger-scale view of a downstream end of the annular sheet of [Fig. 3]; and

[0032] [Fig.6] [Fig.6] is viewed similarly to that of [Fig.5] and shows a variant embodiment of the downstream end of the annular sheet. Detailed description of the invention

[0033] Fig. 1 shows a module 10 for an aircraft turbomachine, this turbomachine being here a twin-spool turbojet engine although this example is not limiting.

[0034] Axis A designates the longitudinal axis of the turbomachine.

[0035] 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.

[0036] 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).

[0037] 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.

[0038] 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.

[0039] 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.

[0040] In a known manner, the bottom of chamber 14c is equipped with fuel injection systems 24 into the combustion chamber 14.

[0041] The chamber 14 is supplied with compressed air by the injection system 24, this compressed air being mixed with the fuel supplied by injectors 17.

[0042] The rectifier-diffuser 26 is mounted at the outlet of the wheel 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.

[0043] 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 the chamber 14 and the wheel 22.

[0044] 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 axially fitted into recesses on the outer periphery of the disk 22b in a known manner.

[0045] 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. 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, located upstream of the aforementioned first portion.

[0046] The stator further includes an arrangement of laminations 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.

[0047] In the example shown, the first flange 34 includes an external periphery 34a fixed to the internal periphery of the distributor 28, and an internal periphery 34b fixed to the lamination arrangement 32. Preferably, the internal periphery 34b of the flange 34 includes an annular flange 35 for fixing to the lamination arrangement 32.

[0048] 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, 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.

[0049] In the example shown, two annular sealing gaskets 38, respectively upstream and downstream, are mounted between the second flange 36 and the first flange 34. Each gasket 38 is preferably labyrinth-type and includes annular flaps 38a carried by or formed on the second flange 36 and adapted to cooperate by friction with an abradable ring 38b carried by the first flange 34. Preferably, each gasket 38 is located radially inside the flange 35 and therefore surrounded by this flange 35.

[0050] The arrangement of sheets 32 is both axially intercalated between the wheel 20 and the distributor 28, or here the flanges 36, 38, and radially between the shaft 18 and the combustion chamber 14.

[0051] As its name indicates, the arrangement of sheets 32 is formed by sheets or portions of sheets which allow in particular to guide a part of the air exiting the rectifier-diffuser 26, and in particular the part of the air which bypasses the chamber 14 from the inside.

[0052] Figures 1 and 2 show the air Fl 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 by fl. The remainder of this air enters the chamber 14 or bypasses the chamber 14 externally.

[0053] The arrangement of sheets 32 includes an annular sheet 32a 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 fl, this air fl being intended to flow from upstream to downstream in this first conduit 40.

[0054] The sheet metal 32a extends for example from the inner periphery of the rectifier-diffuser 26, or an annular flange 26c of the rectifier-diffuser 26, to an annular flange 42 for fixing to the flange 35 of the first flange 34.

[0055] In the further illustrated example, an air vent injector 56, which supplies air through orifices 36c of the second flange 36, is axially interposed between flanges 42 and 35. The injector 56 has a radial orientation and comprises a radially external inlet and a radially internal outlet. The air f2, which flows radially through the injector 56, then passes between the sealing gaskets 38, arranged respectively upstream and downstream of the outlet of this injector 56, and then through the orifices 36c of the second flange 36.

[0056] The flange 42 includes axial orifices aligned with orifices of the flange 35 for the passage of fastening elements 44 of the screw-nut type for example.

[0057] The arrangement of sheets 32 includes another annular sheet 32b which surrounds the shaft 18, and in particular the portion of shaft 18a, and which defines with this shaft 18 a second annular conduit 48.

[0058] The sheet metal 32b extends, for example, upstream from the injector 56.

[0059] The arrangement of sheets 32 includes another annular sheet 32c which is located just downstream of the wheel 20 and which extends radially from the inside out from the second sheet 32b to the outlet of the wheel 20 and the flange 26c of the rectifier-diffuser 26.

[0060] The sheet metal 32c extends for example from the upstream end of the sheet metal 32b to the inner periphery or flange 26c of the rectifier-diffuser 26.

[0061] 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 the sheet 32a, internally by the sheet 32, upstream by the sheet 32c, and downstream by the injector 56 at least in part.

[0062] The arrangement of sheets 32 may include annular stiffening ribs 52. In the example shown, this is the case for sheet 32b. The ribs 52 are located here inside the internal cavity 54 of the arrangement of sheets 32.

[0063] We will now describe in more detail the sheet metal 32b which defines the internal periphery of the cavity 54.

[0064] The sheet 32b includes an upstream end 32b 1 having an external cylindrical shrink-fit surface 60 on a part of the arrangement of sheets 32, and in particular on the radially internal end 32c 1 of the sheet 32c (figures 2-4).

[0065] The sheet 32b includes a downstream end 32b2 which includes an internal cylindrical surface 62 adapted to slide axially on another part of the arrangement of sheets 32 or an element connected to this arrangement of sheets 32, and in particular on the injector 56 as seen in the drawings (figures 3 and 5).

[0066] The upstream end 32b 1 of the sheet 32b may include a cylindrical rim 64 oriented towards the wheel 20 and having the shrink-fitting surface 60.

[0067] The upstream end 32b 1 of the sheet 32b may include an annular rib 66 which extends radially outwards from the shrink-fitting surface 60. This rib 66 forms an axial stop at the radially internal end 32c 1 of the sheet 32c.

[0068] The downstream end 32b2 of the sheet 32b may include a cylindrical rim 68 oriented downstream and having the internal cylindrical surface 62.

[0069] The downstream end 32b2 of the sheet 32b may include an annular rib 70 which extends radially outwards from the cylindrical rim 68, and in particular the downstream free end of this rim.

[0070] The cylindrical rim 68 may include at its upstream end of connection to the rest of the sheet 32b an annular groove 72 opening radially inwards ([Fig.5]).

[0071] In the embodiment shown in [Fig. 6], an annular weld bead 74 is deposited in the groove 72 and at the connection with the rest of the sheet 32b. This weld bead 74 defines an annular surface 74a which is perpendicular to the X axis and downstream in order to form an axial support for the element and in particular the injector 56.

[0072] Advantageously, the internal cylindrical surface 62 has an axial dimension L2 greater than that L1 of the shrink-fit surface 60, or at least twice greater than that L1 of the shrink-fit surface 60 (figures 4 and 5).

[0073] Advantageously, the internal cylindrical surface 62 has a diameter D2 equal to that DI of the shrink-fit surface 60, to within + / -10% (figures 4 and 5).

[0074] In the example shown, the plate 32b comprises a frustoconical upstream section 76 converging downstream and having its end of largest diameter connected to the upstream end 32b1. The plate 32b comprises a frustoconical downstream section 78 converging upstream and having its end of largest diameter connected to the downstream end 32b2. The plate 32b further comprises an intermediate cylindrical section 80 extending between the ends of smaller diameters of the upstream and downstream sections 76, 78.

[0075] The sheet 32b preferably comprises external annular stiffening ribs 52 and / or at least one annular row of air passages 82. The ribs 52 are preferably located on the intermediate section 80. The row of holes 82 is preferably located on the downstream section 78.

[0076] Shrink-fitting the sheet 32b at its upstream end ensures that this sheet is held in relation to the rest of the sheet arrangement 32. The axially sliding mounting of the sheet 32b at its downstream end compensates for thermal expansion and relative movements between the parts during operation, thus guaranteeing an optimal lifespan for the sheet arrangement 32. The orifices 32 prevent the cavity 54 to be totally closed and sealed and to have an internal pressure close to that outside the cavity 54 and in particular at the level of the conduit 48. The ribs 52 limit the deformations of the sheet 32b, in particular in torsion.

Claims

Demands

1. Module (10) for an aircraft turbomachine, said module (10) comprising: - a rotor comprising a centrifugal compressor impeller (20) (12) and a turbine impeller (22) (16), the impeller (20) and the impeller (22) being connected to each other by a shaft (18) movable around 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 impeller (22), - 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), and - a lamination arrangement (32) for connecting the rectifier-diffuser (26) to the distributor (28), this lamination arrangement (32) also forming part of the stator and defining an annular cavity (54) which extends around and at a distance from said shaft (18) and is surrounded at a distance by the chamber (14), characterized in that the lamination arrangement (32) comprises a first annular lamination (32b) which defines an internal periphery of said cavity (54) and which comprises an upstream end (32b1) having an external cylindrical surface (60) for shrink-fitting on a part of the lamination arrangement (32), and a downstream end (32b2) which comprises an internal cylindrical surface (62) adapted to slide axially on another part of the lamination arrangement (32) or an element connected to this lamination arrangement (32).

2. Module (10) according to claim 1, wherein the upstream end (32b 1) of the first sheet (32b) comprises a cylindrical rim (64) oriented towards the wheel (20) and comprising said shrink-fitting surface (60).

3. Module (10) according to claim 1 or 2, wherein the upstream end (32b 1) of the first sheet (32b) comprises an annular rib (66) which extends radially outwards from said shrink-fitting surface (60).

4. Module (10) according to any one of the preceding claims, wherein the downstream end (32b2) of the first sheet (32b) comprises a cylindrical rim (68) oriented downstream and comprising said internal cylindrical surface (62).

5. Module (10) according to claim 4, wherein the downstream end (32b2) of the first sheet (32b) comprises an annular rib (70) which extends radially outwards from said cylindrical rim (68).

6. Module (10) according to claim 4 or 5, wherein the cylindrical rim (68) comprises at its upstream end of connection to the rest of the first sheet (32b) an annular groove (72) opening radially inwards.

7. Module (10) according to claim 6, wherein an annular weld bead (74) is deposited in the groove (72) and at the connection with the rest of the first sheet (32b), this weld bead (74) defining an annular surface (74a) which is perpendicular to said axis (X) and downstream in order to form an axial support for said element.

8. Module (10) according to any one of the preceding claims, wherein said internal cylindrical surface (62) has an axial dimension (L2) greater than that (L1) of said shrink-fitting surface (60), or at least twice greater than that (L1) of said shrink-fitting surface (60).

9. Module (10) according to any one of the preceding claims, wherein the first sheet (32b) comprises an upstream frustoconical section (76) converging downstream and having its end of largest diameter connected to said upstream end (32b 1).

10. Module (10) according to any one of the preceding claims, wherein the first sheet (32b) comprises a downstream frustoconical section (78) converging upstream and having its end of largest diameter connected to said downstream end (32b2).

11. Module according to all claims 9 and 10, wherein the first sheet (32) comprises an intermediate cylindrical section (80) extending between smaller diameter ends of the upstream and downstream sections (76, 78).

12. Module (10) according to any one of the preceding claims, wherein the first sheet (32b) comprises external annular ribs (52) stiffening and / or at least one annular row of air passage orifices (82).

13. Module according to claim 12 depending on claim 11, wherein the ribs (52) are located on the intermediate section (80) and / or said at least one row of holes (82) is located on the downstream section (78).

14. Module (10) according to any one of the preceding claims, wherein the upstream end (32bl) of the first sheet (32b) is shrunk to a radially internal end of a second annular sheet (32c) fixed to the rectifier-diffuser (26), and the downstream end (32b2) of the first sheet (32b) is radially supported on an external cylindrical surface of a ventilation air injector (56), this ventilation injector (56) being fixed to a downstream end of a third annular sheet (32a) which defines an external periphery of the cavity (54) and of which an upstream end is fixed to the rectifier-diffuser (26).

15. Turbomachine for an aircraft, comprising at least one module (10) according to any one of the preceding claims.

Images