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), - a stator-diffuser (26) mounted at the outlet of the stator (20), - a turbine distributor (28) mounted upstream of the wheel (22), - an annular combustion chamber (14) axially interposed between the stator-diffuser (26) and the distributor (28), and carrying fuel injection systems (24), and - a lamination (32) connecting the stator-diffuser (26) to the distributor (28), this lamination (32) including an air injector (56) at the injection systems (24). 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, internal and external respectively, which are connected upstream by an annular chamber floor. This chamber floor carries an annular row of fuel injection systems within the chamber. 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 impeller shaft connecting to the turbine wheel. These solutions employ a lamination arrangement that connects the rectifier-diffuser to the distributor.

[0011] In document FR-A1-2 904 036, for example, [Fig. 4] shows an arrangement of metal sheets 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.

[0012] The invention proposes an improvement to this technology which makes it possible to improve the supply of compressed air to the chamber. Summary of the invention

[0013] The invention relates to a module for an aircraft turbomachine, this module comprising:

[0014] - a rotor comprising a centrifugal compressor impeller and a movable impeller turbine, the impeller and the rotating wheel being connected to each other by a rotating shaft that pivots around an axis,

[0015] - a stator comprising a rectifier-diffuser mounted at the output of the wheel and a turbine distributor mounted upstream of the impeller,

[0016] - 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 floor, the chamber floor carrying an annular row of fuel injection systems inside the chamber, and

[0017] - an arrangement of sheet metal (or portions of sheet metal) for connecting the rectifier-diffuser to distributor, this arrangement of sheet metal also forms part of the stator and comprises:

[0018] + a first annular sheet or portion of annular sheet 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,

[0019] + a second annular sheet or portion of annular sheet surrounding said shaft and which, with this tree, 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

[0020] + a third annular sheet or portion of annular sheet which is located, from a just preference, downstream of the wheel and extending radially from the inside to the outside from the second sheet or portion of sheet to the outlet of the wheel, this third sheet or portion of sheet defining with a radial face downstream of the wheel 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,

[0021] characterized in that the sheet metal arrangement further comprises at least one air injector which is supplied with air taken from the third conduit and which leads to the fuel injection systems for the purpose of supplying them with this air taken from them.

[0022] 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 injection systems. To this end, the lamination arrangement includes at least one air injector which is supplied with air drawn from the third duct and which supplies the injection systems with this drawn air.The combustion chamber is thus supplied with compressed air at a higher pressure than the air exiting the rectifier-diffuser, which is particularly advantageous as it significantly improves chamber performance. Although the temperature of the compressed air exiting the rectifier-diffuser may 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 its circulation within the injector is generally at the temperature of the air exiting the rectifier-diffuser.

[0023] The sheet metal arrangement can be an arrangement of one or more sheet(s) or of one or more portion(s) of sheet metal.

[0024] The module according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0025] — said at least one air injector is opposite the injection systems of fuel ; - each of the injection systems includes a support and centering element for an injector head, this element having spirals and a mixing bowl located downstream of the spirals and having air passage orifices, said at least one injector being oriented to open towards the mixing bowls of the injection systems; - the mixing bowl is connected on one side to the augers and on the other side to an external annular collar which is mounted to slide in a sleeve, the collar defining around the augers an annular space for the passage of air supplied by said at least one injector; - said at least one injector comprises an annular row of nozzles which extend along a main longitudinal extension direction; - each of the nozzles has a generally rectilinear shape or orientation; - each of the nozzles extends from upstream to downstream and radially towards the outside; - the number of nozzles is equal to the number of injection systems;

[0026] — the nozzles are oriented respectively towards the mixing bowls of the systems injection, and preferably towards the aforementioned annular spaces; - the nozzles are formed by tubes attached and fixed to an annular overthickness of the sheet metal arrangement; - said at least one injector includes an inlet located at the outlet of the impeller, and an outlet which leads to the fuel injection systems; - the arrangement of sheet metal forms an internal annular cavity which is radially interposed between the shaft and the combustion chamber;

[0027] — the cavity is completely sealed;

[0028] — the arrangement of the sheets forms an internal annular cavity which is intercalated radially between the shaft and the combustion chamber;

[0029] the sheet metal arrangement includes at its outer periphery at least one opening radiating outwards towards the outside on the side of the chamber, and at its inner periphery at least a second opening radially outwards towards the inside on the side of the shaft; - the sheet metal arrangement includes an annular flange for fixing to an annular flange, called the first flange, which is integral with said distributor, the first flange being mounted radially under the distributor; - the flange includes radially oriented lunules or lights for the fluidic communication of said first conduit with said second conduit;

[0030] — the flange is devoid of axial air passage orifices;

[0031] — the third annular sheet or portion of annular sheet is located opposite the spinning wheel.

[0032] The present invention also relates to an aircraft turbomachine, comprising at least one module as described above. Brief description of the figures

[0033] 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:

[0034] [Fig-1] [Fig.1] is a schematic half-view in axial section of a module according the invention for an aircraft turbomachine,

[0035] [Fig.2] [Fig.2] is a schematic cross-sectional and perspective view of a system fuel injection for a combustion chamber;

[0036] [Fig.3] [Fig.3] is another larger-scale view of part of [Fig.1],

[0037] [Fig.4] [Fig.4] is another larger-scale view of part of [Fig.1]; and

[0038] [Fig. 5] [Fig. 5] is a view similar to that of [Fig. 1] and illustrates a variant of the realization of the invention. Detailed description of the invention

[0039] 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.

[0040] Axis A designates the longitudinal axis of the turbomachine.

[0041] 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.

[0042] 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).

[0043] 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 in rotation around the axis A.

[0044] 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.

[0045] 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.

[0046] In a known manner, the bottom of chamber 14c is equipped with fuel injection systems 24 into the combustion chamber 14.

[0047] With reference to [Fig. 2], an injection system 24 comprises, from upstream to downstream, means 19a for supporting and centering the head of an injector 17 (for example, in the form of a support and centering member 19a), means 19b for injecting air (for example, annular nozzles 19b), and means 19c for diffusing an air-fuel mixture into the chamber. The injection system 24 further comprises an annular sleeve 31 and a ring 4L

[0048] The chamber 14 is thus supplied with compressed air by the injection system 24, this compressed air being mixed with the fuel supplied by the injectors 17.

[0049] The support and centering member 19a of each injection system 19 comprises a frustoconical surface 23a which is flared upstream and which is connected by its downstream end, which is therefore the one with the smaller diameter, to the upstream end of a cylindrical surface 23b. The injector head 17 cooperates by sliding with the frustoconical surface 23a to center the injector 17, and then with the cylindrical surface 23b. The injector head 17 is then inserted into the support and centering member 19a.

[0050] The support and centering member 19a has annular spirals 19b extending around an axis C and configured to form an airflow intended to mix with the fuel injected by the injector head 17. In the example shown, the axis C forms an axis of revolution for the injection system 19. A frustoconical mixing bowl 25 is mounted downstream of the spirals 19b for atomizing the air / fuel mixture entering the combustion chamber 14.

[0051] The support and centering member 19a further comprises an annular collar 27 extending radially outwards from the axis C and including at least one radially external tab 27a. The support and centering member 19a is slidably mounted between the annular sleeve 31 and the ring 4L

[0052] The annular augers 19b comprise a first stage of blades 19b 1, and a second stage of blades 19b2 which have the function of driving the air in rotation around the longitudinal axis C of the injection system 19. The blades of the stages 19b 1, 19b2 can be in the same direction or in opposite directions.

[0053] The annular sleeve 31 is fixed to the bottom of the chamber 14c, and is, for example, brazed to the bottom of the chamber 14c. The annular sleeve 31 extends around the axis C and has a radial annular surface 31a forming a sliding surface. Each tab 27a is able to slide on the sliding surface 31a of the sleeve 31.

[0054] The ring 41 is attached and fixed to the sleeve 31. The ring 41 extends around the axis C and has a radial annular surface 41a located opposite the radial annular surface 31a of the sleeve 31. The radial annular surfaces 31a, 41a of the sleeve 31 and of the ring 41 are substantially parallel and define between them an annular space for housing and sliding of the collar 27, more precisely of the tabs 27a of the collar 27.

[0055] It can be seen in [Fig.2] that the mixing bowl 25 has air passage orifices 25a and is connected on one side to the augers 19b and on the other side to the external annular collar 27. The collar 27 defines around the augers 19b an annular space E for air passage up to the mixing bowl 25.

[0056] Module 10 further includes several other stator elements including in particular a rectifier-diffuser 26 and a distributor 28 of the turbine 16.

[0057] 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.

[0058] 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 moving wheel 22.

[0059] The moving 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.

[0060] The rotating 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. The ferrules 28b, 28c can be formed by platforms placed circumferentially end to end.

[0061] The stator further comprises 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. The first flange 34 is mounted radially under the distributor 28.

[0062] 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.

[0063] A second annular flange 36 can be fixed to the movable 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.

[0064] 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-shaped and includes annular flaps 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 therefore surrounded by this flange 35.

[0065] 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.

[0066] 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 radially from the inside.

[0067] 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 as f2. The remainder of this air enters the chamber 14 or bypasses the chamber 14 radially externally.

[0068] 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 fl, this air fl being intended to flow from upstream to downstream in this first conduit 40.

[0069] 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.

[0070] In the example shown, the sheet metal 32a essentially comprises two portions, namely a first upstream portion 32al which is cylindrical, and a second downstream portion 32a2 which is frustoconical and converges downstream. The first portion 32a 1 has an upstream end connected to the inner periphery of the rectifier-diffuser 26 and a downstream end which is located inside the inner wall 14a of the chamber 14, and which 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 14 and its inner periphery is connected to the flange 42.

[0071] 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.

[0072] 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).

[0073] The arrangement of sheets 32 includes a second annular sheet 32b or portion of annular sheet that 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.

[0074] The sheet metal 32b extends for example upstream from the flange 42 of the sheet metal 32a.

[0075] 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.

[0076] The first portion 32b 1 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.

[0077] The first portion 32b 1 can be located radially inside the second portion 32a2 and can therefore be surrounded by this portion 32a2 as in the example shown.

[0078] The second portion 32b2 can be located radially inside the first portion 32a 1.

[0079] The arrangement of sheets 32 includes a third annular sheet 32c or portion of annular sheet which is located, preferably just downstream (or opposite) the wheel 20 and which extends radially from the inside out from the second sheet 32b to the exit of the wheel 20.

[0080] 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.

[0081] The sheet metal 32c extends for example from the upstream end of the sheet metal 32b to the inner periphery of the rectifier-diffuser 26. The sheets metals 32a and 32c can be connected to the rectifier-diffuser 26 in the same area as in the example shown.

[0082] In the example shown, the sheet metal 32c essentially comprises two portions: a first downstream portion 32c1, which is frustoconical and flares upstream, and a second upstream portion 32c2, which is radial and extends radially 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, in particular to the upstream end of the sheet metal 32a.

[0083] The sheet 32c can be located radially inside the sheet 32a, and therefore be surrounded by the sheet 32a. In particular, the portions 32c 1, 32c2 can be surrounded by the first portion 32a 1 of the sheet 32a.

[0084] The first portion 32c 1 can be located axially opposite portion 32b 1. The second portion 32c2 can be located axially opposite portion 32a2 and / or flange 42.

[0085] 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.

[0086] The arrangement of sheets 32 may include annular stiffening ribs 52. In the example shown, this is the case, for example, of sheet 32 ​​and in particular of its second portion 32b2. The ribs 52 are located radially inside the internal cavity 54 of the arrangement of sheets 32.

[0087] In the embodiment of [Fig. 1], the cavity 54 is totally closed and preferably sealed.

[0088] In the embodiment variant of [Fig.5], the cavity 54 is on the contrary open and includes at its external periphery at least one opening 64 opening radially outwards on the side of the chamber 14, and in particular of its internal wall 14a, and at its internal periphery at least a second opening 66 opening radially inwards on the side of the shaft 18, and in particular of the portion of shaft 18a.

[0089] The particularity of module 10 is that it also includes at least one air injector 56 which allows air to be injected at the level of the injection systems 24 of chamber 14.

[0090] The arrangement of sheet metal 32 can be formed in one piece with at least a part of the injector 56 as can be seen in the drawings.

[0091] It can be seen in particular in the drawings that the arrangement of sheets 32 can be formed in one piece, including with the flange 42 and the straightener-diffuser 26.

[0092] Advantageously, the injector 56 includes an inlet 56a located at the outlet of the wheel 20, and an outlet 56b directed towards the fuel injection systems 24 and ideally arranged to open up in relation to these systems ([Fig.3]).

[0093] Advantageously, and as illustrated in the drawings, the injector 56 comprises an annular row of nozzles 58. These nozzles 58 advantageously extend along a main longitudinal extension direction.

[0094] Each of the nozzles 58 preferably has a generally straight shape to better guide the air drawn in.

[0095] In the example shown, each of the nozzles 58 extends from upstream to downstream radially outwards.

[0096] The number of nozzles 58 is preferably equal to the number of injection systems 24, so as to allow a nozzle 58 to be associated with each of these systems 24.

[0097] As can be seen in Figures 1 and 3 for example, the nozzles 58 can be oriented respectively to open towards the mixing bowls 25 of the injection systems 24, and preferably to open towards the aforementioned annular spaces E.

[0098] The nozzles 58 can be formed by tubes attached to and fixed onto an annular overhang 60 of the sheet metal arrangement 32. The tubes have internal passages 62 which open at one end towards the injection systems 24, and which are in fluidic communication at the opposite end with bores 63 formed in the overhang 60. These bores 63 are aligned with the internal passages 62 of the tubes and open at their upstream ends to the outer periphery of the sheet metal 32c, and in particular to its portion 32c2. It is therefore understood that the air circulates in the module 10 in the following manner. Air Fl exits the centrifugal compressor 12 at a given pressure and circulates in the rectifier-diffuser 26 which diffuses air F2. Part of this air fl bypasses chamber 14 from the inside and circulates in duct 40 and passes through the lunes 46. The air f2, f3 then circulates in duct 48 as far as duct 50.When the air f4 rises along the downstream face 20a of the wheel 20, it is further compressed by vortex effect and has a pressure greater than that at the outlet of the wheel 20. This air f5 enters the injector 56, and in particular the nozzles 58, through the inlets 56a, and is conveyed to the outlet 56b where the air f6 is injected at the mixing bowls 25 through the spaces E of the injection systems 24.

[0099] Although the temperature of the air f4 may also increase due to viscous friction with the wheel 20, this air will have time to return to a temperature close to or identical to air F2 or fl due to the passage of air f5 through injector 56 which is globally at the temperature of air F2, fl.

[0100] The air circulation in the embodiment of [Fig.5] is slightly different. Air Fl exits the centrifugal compressor 12 at a given pressure and flows through the rectifier-diffuser 26 which diffuses air F2. Air fl bypasses chamber 14 internally and flows through conduit 40. Part of this air fl' passes through opening 64 and enters cavity 54. The remaining air f2 continues to flow through conduit 40 and passes through the lunules 46 to enter cavity 54 directly. The air f3 contained in cavity 54 exits through opening 66 and enters conduit 48 to flow from downstream to upstream into 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 enters the injector 56, and in particular enters the nozzles 58, through the inlets 56a, and is routed to the outlet 56b where the air f6 is injected at the mixing bowls 25 through the spaces E of the injection systems 24.

[0101] In this embodiment, even if the conduits 40, 48 do not communicate directly with each other through the lunules 46, the conduit 48 remains supplied with air by the conduit 40 insofar as part of the air which flows in the conduit 40 passes through the cavity 54 to supply the conduit 50.

[0102] Although the temperature of the air f4 can also increase by viscous friction with the wheel 20, this air will have time to recover a temperature close to or identical to the air F2 or fl due to the passage of the air f5 through the injector 56 which is globally at the temperature of the air F2, fl.

[0103] Although not shown, fins could be present on the radial face 20a of the wheel in order to accentuate the air recompression phenomenon f4.

[0104] In general, the invention makes it possible to supply injection systems with air at a higher pressure and with an unchanged temperature. This improves the performance of the combustion chamber by improving the injection of the air-fuel mixture into the chamber.

Claims

1. Demands 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 output of the wheel (20) and a turbine distributor (28) mounted upstream of the rotating 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), the combustion chamber (14) having two coaxial annular walls, respectively internal (14a) and external (14b), which are connected upstream by an annular chamber bottom (14c), the chamber bottom (14c) carrying an annular row of fuel injection systems (24) inside the chamber (14), 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 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 (fl) exiting the rectifier-diffuser (26), the air (fl) being intended to flow from upstream to downstream in this first duct (40), + a second annular plate (32b) or portion of annular plate surrounding said shaft (18) and defining 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 located downstream of the impeller (20) and extending 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 arrangement of sheets (32) further comprises at least one air injector (56) which is supplied with air taken from the third duct (50) and which opens into the fuel injection systems (24) for the purpose of supplying them with this taken air.

2. Module (10) according to claim 1, wherein each of the injection systems (24) comprises a support and centering member (19a) for an injector head (17), said member (19a) having augers (19b) and a mixing bowl (25) located downstream of the augers (19b) and having air passage orifices (25a), said at least one injector (56) being oriented to open towards the mixing bowls (25) of the injection systems (24).

3. Module (10) according to claim 2, wherein the mixing bowl (25) is connected on one side to the augers (19b) and on the other side to an external annular collar (27) which is slidably mounted in a sleeve (31), the collar (27) defining around the augers (19b) an annular space (E) for the passage of air supplied by said at least one injector (56).

4. Module (10) according to any one of the preceding claims, wherein said at least one injector (56) comprises an inlet (56a) located at the outlet of the impeller (20), and an outlet (56b) which leads to the fuel injection systems (24).

5. Module (10) according to any one of the preceding claims, wherein said at least one injector (56) comprises an annular row of nozzles (58) extending along a main longitudinal extension direction.

6. Module (10) according to claim 5, wherein each of the nozzles (58) has a generally rectilinear shape.

7. Module (10) according to claim 5 or 6, wherein each of the nozzles (58) extends from upstream to downstream and radially outwards.

8. Module (10) according to any one of claims 5 to 7, depending on claim 2 or 3, wherein the number of nozzles (58) is equal to the number of injection systems (24).

9. Module (10) according to any one of claims 5 to 8, wherein the nozzles (58) are formed by tubes attached and fixed to an annular overthickness (60) of the sheet metal arrangement (32).

10. Module (10) according to any one of claims 1 to 9, wherein the arrangement of sheets (32) forms an internal annular cavity (54) which is radially intercalated between the shaft (18) and the combustion chamber (14).

11. Module (10) according to any one of claims 1 to 10, wherein the arrangement of sheets (32) comprises at its outer periphery at least one opening (64) opening radially outwards on the side of the chamber (14), and at its inner periphery at least one second opening (66) opening radially inwards on the side of the shaft (18).

12. Module (10) according to any one of the preceding claims, wherein the arrangement of sheets (32) includes an annular flange (42) for attachment to an annular flange (34), called the first flange, integral with said distributor (28), the first flange (34) being mounted radially under the distributor (28).

13. Module (10) according to the preceding claim, wherein the flange (42) comprises radially oriented lunules (46) or lights for the fluidic communication of said first conduit (40) with said second conduit (48).

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

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