RECOVERED CYCLE AIRCRAFT TURBOMACHINE

Abstract

Aircraft turbomachine (10), comprising: - a centrifugal compressor (14), - a combustion chamber (24), - a turbine (30) comprising a bladed annular distributor (31) mounted at the outlet of the chamber (24), and a bladed wheel (33) located downstream of this distributor (31), the bladed wheel (33) being surrounded by a sealing ring (35) which is carried by an annular support (37) connected to said casing (29), - a system (32) for diffusing and straightening an airflow exiting the centrifugal compressor (14) to supply the combustion chamber (24), - a heat exchanger (38) connected by volutes (40) to the diffusion and straightening system (32), and - a circuit (50) for drawing in air and circulating the drawn air up to the distributor (31) and / or the sealing ring (35) for the purpose of cooling it / them. Figure for the summary: Figure 4

Description

Title of the invention: RECOVERED CYCLE AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to a recovered cycle aircraft turbomachine. Technical background

[0002] An aircraft turbomachine comprises a gas generator having, from upstream to downstream in the direction of gas flow, at least one compressor, one combustion chamber, and at least one turbine. The compressor is supplied with air and compresses it. The compressed air is mixed with fuel and burned in the combustion chamber, which supplies combustion gases to the turbine. These combustion gases expand in the turbine and rotate its rotor, which in turn drives, via a common shaft, the compressor rotor.

[0003] A turbomachine can be equipped with one or more bodies, each comprising a compressor rotor connected by a shaft to a turbine rotor.

[0004] There are also turbomachines where a free turbine is mounted downstream of the turbomachine body(ies). A turbine is free insofar as its rotor is not connected by a shaft to a compressor rotor.

[0005] It is thus understood that a turbomachine can comprise several successive compressors (for example a low pressure compressor followed by a high pressure compressor), as well as several successive turbines (for example a high pressure turbine followed by a free turbine or a low pressure turbine).

[0006] In the present application, a conventional cycle turbomachine means a turbomachine in which the compressed air exiting the compressor(s) directly feeds the combustion chamber.

[0007] Conversely, a recovered cycle turbomachine is defined as a turbomachine in which the combustion gases flowing from the turbine(s) are used to preheat the compressed air exiting the compressor(s) and intended to supply the combustion chamber. This technology improves the turbomachine's performance because the amount of fuel required to achieve the same power output is less than that required in a conventional cycle turbomachine.

[0008] Fig. 1 represents in a very schematic way a recovered cycle turbomachine.

[0009] The turbomachine 1 comprises, from upstream to downstream, a compressor 2, a combustion chamber 3, a turbine 4 and a free turbine 5. The rotors of the compressor 3 and the turbine 4 are connected together by a shaft 6 and form a single body.

[0010] The turbomachine 1 includes a heat exchanger 7, the first circuit of which is supplied with combustion gases taken from the outlet of the free turbine 5. The exchanger 7 includes a second circuit which is supplied with compressed air exiting the compressor 2 and which provides heated compressed air to the combustion chamber 3.

[0011] The integration of this technology can be made complex when the compressor 2 is of the centrifugal type. A centrifugal compressor is a compressor which has an inlet oriented parallel to the longitudinal axis of the turbomachine, and an outlet which is oriented radially with respect to this axis.

[0012] This type of compressor is associated with a compressed air flow diffusion and rectification system. This system comprises a diffuser-rectifier assembly and therefore includes an annular diffuser which is oriented substantially radially and aligned with the outlet of the centrifugal compressor, and an annular rectifier which is oriented substantially axially to direct the compressed air flow towards the combustion chamber.

[0013] An integration solution for this technology has already been proposed in the past and consists of using a set of two volutes. A volute is a conduit wound spirally around an axis, the cross-section of which varies. Document FR-A1-3 111 666 describes a recovered-cycle aircraft turbomachine incorporating this solution.

[0014] Increasing the temperature of the compressed air entering the chamber directly leads to an increase in the temperature of the turbine's secondary flow. The temperature of the primary flow exiting the chamber is not increased because less fuel is injected into the chamber to control this temperature. However, the temperature of the secondary flow exiting the chamber, which is used in particular for thermal control of the turbine components, does increase. The turbine comprises a bladed annular distributor followed by a bladed impeller surrounded by a sealing ring. The increase in the temperature of the secondary flow air results in an increase in the temperature of the distributor metal and the sealing ring that controls the aforementioned clearance.

[0015] The consequence of this temperature increase leads to a degradation of the service life of the distributor and the ring as well as a significant loss of turbine performance.

[0016] It is known to cool the distributor and the sealing ring during operation. A conventional solution is to draw compressed air from the compressor outlet and route the extracted air to the distributor. For example, this air drawn from the compressor can then pass through internal channels of the distributor to reach the sealing ring for ventilation purposes (see document FR-A1-3 128 971).

[0017] However, this solution of drawing air from the compressor outlet is not always feasible and impacts the efficiency of the heat exchanger and the turbomachine. Furthermore, this solution may not be sufficient to cool a distributor and a sealing ring in a recirculating turbomachine.

[0018] The present invention proposes a solution to at least some of the problems mentioned above. Summary of the invention

[0019] The invention relates to an aircraft turbomachine, comprising:

[0020] - a centrifugal compressor extending around an axis,

[0021] - a combustion chamber extending around the axis, this chamber of combustion comprising two walls, respectively internal and external, the external wall of the chamber being surrounded by an annular casing,

[0022] - a turbine extending around the axis and comprising an annular distributor bladed rotor mounted at the outlet of the chamber, and a bladed wheel located downstream of this distributor, the distributor and the wheel being located radially inside the inner wall of the chamber, and the bladed wheel being surrounded by a sealing ring which is carried by an annular support connected to said casing,

[0023] - a system for diffusing and straightening an airflow exiting the compressor centrifugal force is used to supply the combustion chamber; this system is mounted at the outlet of the centrifugal compressor.

[0024] - a heat exchanger comprising a first circuit supplied with gas exhaust from the turbomachine, and a second circuit connected by volutes to the diffusion and rectification system, and

[0025] - an air intake and circulation circuit for intake air up to the distributor and / or to the sealing ring for the purpose of sounding the cooling system,

[0026] characterized in that said circuit comprises: - at least one air intake opening leading into the volutes, preferably upstream of the heat exchanger,

[0027] - at least one sampled air passage, which is defined at least in part by said annular support extending to the distributor and / or the sealing ring for the purpose of cooling it / them with the extracted air, this air passage being located at least partially radially inside the internal wall of the chamber, and

[0028] - at least one intake air circulation duct comprising a first one end connected to said at least one opening and a second opposite end connected to said passage for the purpose of supplying it with extracted air.

[0029] According to the invention, air is drawn from the volutes and not directly from The air is drawn from the compressor or rectifier outlet. For this purpose, at least one air intake opening leads into the volutes, for example, into one of the volutes. Air is thus drawn from the volutes, preferably upstream of the passage through the heat exchanger and therefore before the air is heated in the exchanger. Air circulating in the volutes is thus drawn through this opening. This drawn air is intended to flow through a duct, from the opening to an air passage that is at least partially defined by the annular support of the turbine sealing ring. The invention thus proposes to bypass the chamber and prevent the compressed air drawn from the volutes from being heated by the chamber and also from mixing with the warmer air exiting the heat exchanger. The invention therefore makes it possible to ventilate the distributor and / or the sealing ring with air at an optimal temperature in a recirculating cycle turbine.

[0030] In the present application, the term "volute" encompasses any conduit peripheral to the compressor and / or the combustion chamber.

[0031] The turbomachine according to the invention may comprise one or more of the following stages or features, considered independently of each other or in combination with each other: - the annular support comprises a first axial end from which the said sealing ring is suspended, and a second axial end which comprises an annular flange for fixing to the housing by screws or bolts; - the second end of said at least one conduit is connected to said passage by orifices which are formed at the level of the flange of the annular support, and which have for example an orientation parallel to said axis; - the holes are formed in the flange and in the housing, or in the screws or bolts fixing this flange; - said passage extends over the entire axial extent of the annular support which defines an internal annular surface of this passage, an annular veil being interposed radially between the annular support and the internal wall of the chamber and extending axially from the distributor to the casing to define an external annular surface of the passage; - the veil comprises a first axial end fixed to the distributor and / or to said internal wall, and a second axial end fixed to the housing; - the veil is at least partly formed by a metal sheet; - the passage is entirely formed within the annular support; - the annular support is of the double-skinned type and comprises two annular skins, respectively internal and external, defining between them said passage; - the passage includes a first axial part located radially at

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[0040] the outside of the annular support, and a second axial part located radially inside the annular support, these two axial parts being connected together by through holes formed in the annular support; - the first axial part is radially delimited between the annular support, and in particular its first axial end, and a wall, preferably annular, extending from the internal wall of the chamber, and the second axial part is formed by one or more pipes or channels extending from the through orifices to said at least one conduit; - the extension wall is connected to the distributor and includes one end in contact with the internal wall of the chamber, and an opposite end in contact with the annular support; — the combustion chamber is annular and its internal and external walls are annular, these walls defining between them an annular combustion zone; — the combustion chamber is sectorized and includes several combustion zones distributed around the axis; — the second circuit of the heat exchanger has an inlet connected by a first volute to an outlet of the diffuser, and an outlet connected by a second volute to an inlet of the rectifier; — said at least one opening is formed in the first volute; the air is thus taken upstream of the exchanger, which makes it possible to take air at a relatively low temperature unlike the air coming out of the exchanger and is intended to supply the chamber; — the first and second volutes are joined and each includes an annular conduit wound around the axis and connected to a first port located at the external periphery of the conduit and oriented in a tangential direction, and a second port located at the internal periphery of the conduit and oriented in a radial direction; — the conduit of each of the volutes has an evolving passage section which is maximum at the level of the first port and minimum at a circumferential end of the conduit opposite the first port. Brief description of the figures 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: [Fig.1] [Fig.1] is a very schematic view of a recovered cycle aircraft turbomachine; [Fig.2] [Fig.2] is a partial schematic axial cross-sectional view of a tur- recovered cycle aircraft engine;

[0041] [Fig.3] [Fig.3] is a schematic perspective view of a set of volutes;

[0042] [Fig.4] [Fig.4] is a partial schematic axial cross-sectional view of a tur- recovered cycle aircraft engine, and represents a first embodiment of the invention;

[0043] [Fig. 5] [Fig. 5] is a larger-scale view of part of [Fig. 4] and shows a passage of extracted air circulation;

[0044] [Fig.6] [Fig.6] is a view similar to that of [Fig.5] and represents a second method of embodiment of the invention.

[0045] [Fig.7] [Fig.7] is a view similar to that of [Fig.5] and represents a third method of embodiment of the invention. Detailed description of the invention

[0046] The [Fig. 1] has already been described in the preceding.

[0047] Figures 2 and 3 illustrate a recovered cycle aircraft turbomachine 10

[0048] The turbomachine 10 is partially shown in [Fig.2] and conventionally comprises at least one compressor, one combustion chamber and at least one turbine. The combustion chamber is, for example, annular.

[0049] In the example shown, the turbomachine 10 comprises two successive compressors 12, 14 which are therefore mounted one after the other and which are both of the centrifugal type.

[0050] The compressors 12, 14 have an annular shape and are coaxial and centered on an axis A which is the longitudinal axis of the turbomachine 10. Each compressor 12, 14 comprises a stator 16 and a bladed rotor 18, called a wheel, which rotates inside the stator 16 and around the axis A.

[0051] Each compressor 12, 14 comprises an inlet 20 oriented axially upstream and an outlet 22 oriented radially outwards with respect to axis A. The terms upstream and downstream here refer to the general flow of air and gas in the turbomachine 10.

[0052] Compressor 14 is thus located downstream of compressor 12.

[0053] The turbomachine 10 of [Fig.2] further comprises a combustion chamber 24 which is located downstream of the compressor 14.

[0054] In the example shown, the combustion chamber 24 comprises two annular walls, respectively internal 24a, and external 24b, which define between them an annular cavity into which compressed air from the compressor 14 and fuel from injectors 26 are injected and mixed. The walls 24a, 24b thus define between them a combustion zone.

[0055] The walls 24a, 24b are connected to each other by a chamber floor 28 which has a annular shape, the walls 24a, 24b and the bottom of chamber 28 including orifices (not visible) for the passage of compressed air from the compressor 14 to supply chamber 24.

[0056] The combustion chamber 24 is surrounded by an external annular casing 29 which notably carries the injectors 26.

[0057] In the example shown, chamber 24 is of the inverted type because its chamber bottom 28 is located on the rear side of this chamber. The outlet of chamber 24 is located on the front side of the chamber and is connected to one or more turbines 30 arranged downstream of the chamber.

[0058] The combustion gases injected into the turbine 30 expand and drive its rotor which is connected by a shaft to the rotor 18 of at least one of the compressors 12, 14 in order to drive them in rotation around the axis A.

[0059] The turbine 30 comprises a bladed annular distributor 31 located at the outlet of the chamber 28, and a bladed impeller 33 downstream of the distributor 31. Conventionally, this impeller 33 is connected to the shaft 18 and comprises a disc carrying blades around its periphery. The impeller 33 is surrounded by a sealing ring 35 which defines a radial clearance around the impeller 33. This radial clearance must be as small as possible and is regulated during operation by venting the ring 35. The distributor 31 must also be ventilated during operation.

[0060] The sealing ring 35 is carried by an annular support 37 which is connected to the housing 29.

[0061] The combustion gases exiting the turbine 30 are then evacuated into a combustion gas exhaust nozzle which is not shown.

[0062] In a conventional cycle turbomachine 10, the connection of the compressor outlet 14 to the combustion chamber 24 is made by an air diffusion and rectification system 32, also called a diffuser-rectifier.

[0063] This system 32 comprises:

[0064] - an annular diffuser 34 which is oriented substantially radially and which comprises at its inner periphery an inlet 34a supplied by the compressor 14 and radially aligned with the latter's outlet 22, and an outlet 34b at its outer periphery which opens radially to the outside; and

[0065] - an annular rectifier 36 which is substantially axially oriented in the example represented and which includes at its upstream end an inlet 36a, and at its downstream end an outlet 36b to supply the combustion chamber 24.

[0066] The diffuser 34 is located upstream of the chamber 24 and its walls 24a, 24b, and the rectifier 36 extends around the chamber 24 and its walls 24a, 24b and inside the housing 29. The diffuser 34 can be fixed by clamping to the stator 16 of the compressor 12 and / or the compressor 14. The rectifier 36 can be fixed by clamping to the housing 29.

[0067] The diffuser 34 and the rectifier 36 can be bladed.

[0068] In a conventional cycle turbomachine 10, the outlet 34b of the diffuser 34 is di directly connected, for example by an L-shaped angled conduit to the inlet 36a of the rectifier 36. Otherwise, the compressed air exiting the compressor 14 directly feeds the combustion chamber 24.

[0069] In a turbomachine 10 with recovered cycle, the compressed air exiting the compressor 14 is heated before being injected into the combustion chamber 24. The invention relates to this type of turbomachine.

[0070] The heating of the compressed air is achieved by means of a heat exchanger 38 on the one hand and a set of two volutes 40 on the other hand.

[0071] The heat exchanger 38 is schematically represented and essentially comprises two circuits 38a, 38b, namely:

[0072] - a first circuit 38a, one input of which 38aa is connected to means of pre exhaust gas lift at the outlet of the turbines 30 or in the aforementioned exhaust nozzle, and an outlet 38ab which can also be connected to the exhaust nozzle for the purpose of releasing these gases into the atmosphere, and

[0073] - a second circuit 38b comprising an input 38ba and an output 38bc connected to the set of 40 volutes.

[0074] The set of volutes 40 is shown in perspective in [Fig.3].

[0075] The assembly 40 comprises two volutes 40a, 40b which are here joined and coaxial.

[0076] Each volute 40a, 40b comprises a conduit spirally wound around an axis which Here is axis A, preferably over at least 360° so that the conduit makes at least one turn on itself.

[0077] Each volute 40a, 40b comprises a first port 42 located at the outer periphery of the conduit and oriented in a tangential direction, and a second port 44 located at the inner periphery of the conduit and oriented in a substantially radial direction.

[0078] The cross-sectional area of ​​the conduit varies along its circumference, preferably progressively. The cross-sectional area is maximum SI at the first port 42 of each volute 40a, 40b and minimum S2 at the circumferential end of the conduit opposite the first port 42.

[0079] The volute assembly 40 is connected to the diffuser 34, the rectifier 36, and the heat exchanger 38 as follows. Volute 40a has its second port 44 connected to the outlet 34b of the diffuser 34 and its first port 42 supplying the inlet 38ba of the second circuit 38b of the heat exchanger 38. The outlet 38bb of this second circuit 38b is connected to the first port 42 of the second volute 40b, whose second port 44 is connected to the inlet 36a of the rectifier 36.

[0080] In the example shown, the volute 40a is located upstream of the volute 40b. The volutes 40a and 40b each have a circular or oval-shaped passage section, of preference over their entire circumferential extent. By oval shape, we mean any elliptical, ovoid, or oblong shape. Other shapes are, however, possible.

[0081] The volutes 40a, 40b can extend around and away from the housing 29 and be fixed to the latter by clamping.

[0082] The invention relates to the sampling of air and the conveyance of this sampled air to the distributor 31 and / or to the sealing ring 35 for the purpose of its / their cooling.

[0083] The invention relates more particularly to a recovered cycle turbomachine as described above.

[0084] Figures 4 and following illustrate embodiments of the turbomachine 10 according to the invention.

[0085] The preceding description can be used to describe all or part of the turbomachine 10 according to the invention, which comprises at least:

[0086] - a centrifugal compressor 14 extending around an axis A,

[0087] - an annular combustion chamber 24 extending around axis A, this combustion chamber 24 comprising two annular walls, respectively internal 24a and external 24b, which define between them an annular combustion chamber, the external wall 24b of the chamber 24 being surrounded by an annular casing 29,

[0088] - a turbine 30 extending around axis A and comprising an annular distributor bladed 31 mounted at the outlet of chamber 28, and a bladed wheel 33 located downstream of this distributor 31, the distributor 31 and the wheel 33 being located radially inside the inner wall 24a of chamber 24, and the bladed wheel 33 being surrounded by a sealing ring 35 which is carried by an annular support 37 connected to said housing 29,

[0089] - a system 32 for diffusing and straightening an airflow exiting the com centrifugal press 14 to supply the combustion chamber 24, this system 32 being mounted at the outlet of the centrifugal compressor 14, and

[0090] - a heat exchanger 38 comprising a first circuit 38a supplied with gas exhaust of the turbomachine, and a second circuit 38b connected by volutes 40 to the diffusion and rectification system 32.

[0091] The turbomachine 10 further includes an air intake circuit 50 and an air intake circulation circuit up to the distributor 31 and / or the sealing ring 35 for the purpose of cooling it / them.

[0092] According to the invention, this circuit 50 comprises, firstly, at least one air intake opening 52 leading into the volutes 40. Figure 4 shows, for example, an opening 52 formed in volute 40a. There may be a single opening 52 in a single volute 40a, 40b, or a single opening 52 in each of the volutes 40a, 40b, or several openings 52 in one or both of the volutes 40a, 40b. volutes 40a, 40b.

[0093] The opening 52 thus allows a portion of the air circulating in the volutes 40 to be taken.

[0094] In the case shown where the air is drawn from the volute 40a, this means that compressed air coming out of the diffuser 34 is drawn before it feeds the exchanger 38 and is therefore heated in the exchanger 38.

[0095] The circuit 50 further comprises at least one intake air circulation duct 54, which is schematically represented by dashed lines. Each duct 54 has a first end 54a connected to the opening 52 or to one of the openings 52, and a second opposite end 54b which is connected to at least one intake air passage 56.

[0096] The air passage 56 is defined at least in part by the annular support 37 and extends to the distributor 31 and / or the sealing ring 35 for the purpose of cooling it / them with the air. As can be seen in the drawings, this air passage 56 is located at least in part radially inside the inner wall 24a of the chamber 24 in order to bypass it from the inside.

[0097] In the examples shown, the annular support 37 has a frustoconical or flared shape downstream and includes an upstream or front end of smaller diameter located on the side of the distributor 31, and a downstream or rear end of larger diameter located on the side of the housing 29.

[0098] In the first embodiment of figures 4 and 5, the annular support 37 includes a first axial end 37a, here upstream or front, from which the sealing ring 35 is suspended, and a second axial end 37b, here downstream or rear, which includes an annular flange 58 for fixing to the housing 29 by screws or bolts 60.

[0099] The second end 54b of the conduit 54 is connected to the passage 56 by orifices 62 which are formed at the level of the flange 58 of the annular support 37, and which have for example an orientation parallel to said axis X.

[0100] The orifices 62 can be formed in the flange 58 and in the housing 29, or in the screws or bolts 60 for fixing this flange 58.

[0101] In the example shown, the passage 56 extends over the entire axial extent of the annular support 37 which defines an internal annular surface 56a of this passage.

[0102] An annular veil 64 is intercalated radially between the annular support 37 and the internal wall 24a of the chamber 24 and extends axially from the distributor 31 to the housing 29 to define an external annular surface 56b of the passage 56.

[0103] The veil 64 comprises a first axial end 64a fixed to the distributor 31 and / or to the inner wall 24a, and a second axial end 64b fixed to the housing 29.

[0104] The veil 64 can be at least partly formed by a metal sheet.

[0105] An annular sealing element 66 can be mounted between the first end 37a of the support 37 and the outer periphery of the distributor 31.

[0106] The arrows in figures 4 and 5 show the path of the air taken from inside the passage 56. The air taken flows from the orifices 62 along the annular support 37, between the support 37 and the web 64, to the distributor 31 and the sealing ring 35. The first end 37a of the support may include orifices 68 for the passage of air from the passage 56 to the sealing ring 35.

[0107] In the second embodiment of [Fig.6], the annular support 37 also includes a first axial end 37a from which the sealing ring 35 is suspended, and a second axial end 37b which includes an annular flange 58 for fixing to the housing 29 by screws or bolts 60.

[0108] The second end 54b of the conduit 54 is connected to the passage 56 by orifices 62 which are formed at the level of the flange 58 of the annular support 37, and which have for example an orientation parallel to said axis X.

[0109] The orifices 62 can be formed in the flange 58 and in the housing 29, or in the screws or bolts 60 for fixing this flange 58.

[0110] In the example shown, the passage 56 is entirely formed in the annular support 37.

[0111] The annular support 37 is for example of the double-skin type and comprises two annular skins, respectively internal 37c and external 37d, defining between them said passage 56.

[0112] An annular sealing element 66 can be mounted between the first end 37a of the support 37 and the outer periphery of the distributor 31.

[0113] The arrows in [Fig.6] show the path of the air taken from inside the passage 56. The air taken flows from the orifices 62 along and inside the annular support 37 to the sealing ring 35. The first end 37a of the support 37 may include orifices 68 for the passage of air from the passage 56 to the sealing ring 35.

[0114] In the third embodiment of [Fig.7], the annular support 37 also includes a first axial end 37a from which the sealing ring 35 is suspended, and a second axial end 37b which includes an annular flange 58 for fixing to the housing 29 by screws or bolts 60.

[0115] In the example shown, the passage 56 comprises a first axial part 56x located radially outside the annular support 37, and a second axial part 56y located radially inside the annular support 37.

[0116] In the example shown, the first part 56x is located upstream of the second part 56y.

[0117] The two axial parts 56x, 56y are connected together by orifices tra- slopes 70 formed in the annular support 37.

[0118] The first axial part 56x is radially delimited between the annular support 37, and in particular its first axial end 37a, and an annular wall 72 of extension of the internal wall 24a of the chamber 24.

[0119] The second axial part 56y is formed by one or more pipes 74 or channels extending from the through orifices 70 to the conduit 54 or to the conduits.

[0120] In the example shown, the extension wall 72 supports the distributor 31 and includes an end 72a connected to the inner wall 24a of the chamber 24, and an opposite end 72b connected to the annular support 37. This opposite end 72b is located downstream of the ports 70 as in the example shown.

[0121] Annular sealing elements 66 can be mounted between the first end 37a of the support 37 and the outer periphery of the distributor 31, and / or between the opposite end 72 of the extension wall 72 and the support 37.

[0122] The arrows in [Fig. 7] show the path of the air drawn from inside the passage 56. The drawn air flows from the pipes 74 along and inside the annular support 37 to the orifices 70 which form a wall penetration. The drawn air then flows from these orifices 70 along and outside the annular support 37 to the distributor 31 and the sealing ring 35. The first end 37a of the support 37 may include orifices 68 for the passage of air from the passage 56 to the sealing ring 35.

Claims

Demands

1. Aircraft turbomachine (10), comprising: - a centrifugal compressor (14) extending around an axis (A), - a combustion chamber (24) extending around the axis (A), this combustion chamber (24) comprising two walls, respectively internal (24a) and external (24b), the external wall (24b) of the chamber (24) being surrounded by an annular casing (29), - a turbine (30) extending around the axis (A) and comprising a bladed annular distributor (31) mounted at the outlet of the chamber (24), and a bladed wheel (33) located downstream of this distributor (31), the distributor (31) and the wheel (33) being located radially inside the inner wall (24a) of the chamber (24), and the bladed wheel (33) being surrounded by a sealing ring (35) which is carried by an annular support (37) connected to said casing (29), - a system (32) for diffusing and straightening an airflow exiting the centrifugal compressor (14) to supply the combustion chamber (24), this system (32) being mounted at the outlet of the centrifugal compressor (14), - a heat exchanger (38) comprising a first circuit (38a) supplied with exhaust gas from the turbomachine (10), and a second circuit (38b) connected by volutes (40) to the diffusion and rectification system (32), and - an air intake circuit (50) and circulation of the intake air to the distributor (31) and / or the sealing ring (35) for the purpose of a cooling probe, characterized in that said circuit (50) comprises: - at least one air intake opening (52) leading into the volutes (40), preferably upstream of the heat exchanger (38), - at least one intake air passage (56), which is defined at least in part by said annular support (37) and which extends to the distributor (31) and / or the sealing ring (35) for the purpose of cooling it / them with the intake air, this intake air passage (56) being located at least in part radially inside the inner wall (24a) of the chamber (24), and - at least one intake air circulation duct (54) having a first end (54a) connected to said at least one opening (52) and a second opposite end (54b) connected to said passage (56) for the purpose of supplying it with intake air.

2. Turbomachine (10) according to claim 1, wherein the annular support (37) comprises a first axial end (37a) from which said sealing ring (35) is suspended, and a second axial end (37b) which comprises an annular flange (58) for fixing to the housing (29) by screws or bolts (60).

3. Turbomachine (10) according to claim 2, wherein the second end (54b) of said at least one conduit (54) is connected to said passage (56) by means of orifices (62) which are formed at the level of the flange (58) of the annular support (37), and which have for example an orientation parallel to said axis (X).

4. Turbomachine (10) according to claim 3, wherein the orifices (62) are formed in the flange (58) and in the housing (29), or in the screws or bolts (60) for fixing this flange (58).

5. Turbomachine (10) according to any one of the preceding claims, wherein said passage (56) extends over the entire axial extent of the annular support (37) which defines an internal annular surface (56a) of this passage (56), an annular web (64) being interposed radially between the annular support (37) and the internal wall (24a) of the chamber (24) and extending axially from the distributor (31) to the casing (29) to define an external annular surface (56b) of the passage (56).

6. Turbomachine (10) according to claim 5, wherein the sail (64) comprises a first axial end (64a) fixed to the distributor (31) and / or to said inner wall (24a), and a second axial end (64b) fixed to the housing (29).

7. Turbomachine (10) according to claim 5 or 6, wherein the sail (64) is at least partly formed by a metal sheet.

8. Turbomachine (10) according to any one of claims 1 to 5, wherein the passage (56) is integrally formed in the annular support (37).

9. Turbomachine (10) according to claim 8, wherein the annular support (37) is of the double-skinned type and comprises two annular skins, respectively inner (37c) and outer (37d), defining between them said passage (56).

10. Turbomachine (10) according to claim 1 or 2, wherein the passage (56) comprises a first axial portion (56x) located ra- diamentally outside the annular support (37), and a second axial part (56y) located radially inside the annular support (37), these two axial parts (56x, 56y) being connected together by through holes (70) formed in the annular support (37).

11. Turbomachine (10) according to claim 10, wherein the first axial part (56x) is radially delimited between the annular support (37), and in particular its first axial end (37a), and a wall (72) extending from the inner wall (24a) of the chamber (24), and the second axial part (56y) is formed by one or more pipes (74) or channels extending from the through ports (70) to said at least one conduit (54).

12. Turbomachine (10) according to claim 11, wherein the extension wall (72) is connected to the distributor (31) and comprises one end (72a) in contact with the inner wall (24a) of the chamber (24), and one opposite end (72b) in contact with the annular support (37).

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