AIRCRAFT TURBOMACHINE AND ASSOCIATED PROCESS

Abstract

AIRCRAFT TURBOMACHINE AND ASSOCIATED METHOD One aspect of the invention relates to an aircraft turbomachine comprising: a compression stage (3, 4) configured to produce fresh air; a gas generation circuit (20) configured to heat the fresh air and produce gas from the heated air; a distributor (7), comprising a gas exhaust circuit and a cooling circuit; the turbomachine (1) being remarkable in that it also comprises a fresh air distribution circuit (21), separate from the gas generation circuit (20), supplied with fresh air by the compression stage (4) and supplying fresh air to the cooling circuit. Figure to be published with the abstract: Figure 3

Description

Title of the invention: AIRCRAFT TURBOMACHINE AND ASSOCIATED METHOD TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of aircraft turbomachines and more particularly of recovered cycle turbomachines, that is to say comprising an air heating system used as an oxidant during the production of gas.

[0002] The present invention also relates to a method of assembling an aircraft turbomachine and more particularly a recovered cycle one. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] An aircraft turbomachine provides mechanical and / or kinetic energy to an aircraft. A subcategory of turbomachines includes turboshaft engines whose produced mechanical energy drives an output shaft. A turboshaft engine is advantageously implemented in a helicopter, the output shaft of the turboshaft engine being, for example, coupled to the helicopter's blade drive system, thus enabling them to rotate.

[0004] [Fig.l] shows a diagram of an aircraft turbomachine 1' according to the prior art and more particularly of a turboshaft engine. The turbomachine 1' comprises a compression stage 2, 3 configured to supply compressed air to a combustion chamber 6'. The combustion chamber 6' produces, from the compressed air, a large quantity of gas. The gas is then expanded in an expansion stage 7, 8, 10, 11 and ejected from the turbomachine by a nozzle 11. The mechanical energy of the turbomachine 1' is partly recovered during the expansion of the gas. When it expands, it drives a free turbine 10, itself linked to a drive system 12, 13 of an output shaft 14 or of a gear train of an accessory relay box 15. The output shaft 14 is intended to provide a substantial part of the mechanical energy of the turbomachine 1', for example to drive the blades of a helicopter.The accessory relay box 15 is intended to drive equipment such as, for example, a hydraulic system or an electric generator.

[0005] The compression stage of the turbomachine 1' as illustrated by [Fig.l] comprises a first compressor 2 called "low pressure compressor", supplied with ambient air and configured to compress the air a first time. The compression stage may also comprise a second compressor 3, called "high pressure compressor", supplied with air by the low pressure compressor 2 and configured to compress the air further. Despite the inherent increase in the temperature of the air during its successive compressions at each stage of a compressor, this temperature is still considered low given the temperatures involved during gas generation. The compressed air produced by the high-pressure compressor is then called "fresh air".

[0006] The fresh air produced by the compression stage is injected directly into the combustion chamber 6', in order to be used as an oxidant during the production of gas. In this case, we are talking about conventional cycle turbomachines.

[0007] Conventional cycle turbomachines do not have the best energy efficiency, in particular because of the temperature difference between the fresh air and the gas produced by the combustion chamber. Energy efficiency is improved by reducing the temperature difference, for example by heating the fresh air before injecting it into the combustion chamber. A technical solution implemented in so-called "recovery cycle" turbomachines consists of recovering part of the heat from the ejected gas to heat the fresh air by means of a heat exchanger. The air injected into the combustion chamber is thus hotter, which improves the efficiency of the turbomachine.

[0008] However, regenerative cycle turbomachines pose new problems. Indeed, part of the air injected into the combustion chamber is not used for gas generation but is used for cooling the parts located downstream of the gas generation. This is for example a fixed-bladed distributor, intended to accelerate and direct the gas before it reaches a turbine wheel. Or a turbine ring, the expansion of which creates a gas leak and reduces the conversion of mechanical energy obtained from the expansion of the gas.

[0009] In a conventional cycle turbomachine, fresh air constitutes a relevant cold source for cooling said parts. On the other hand, in a recuperated cycle turbomachine, the injected air is too hot and can lead to a deterioration in the service life of the distributor and / or the turbine ring as well as a significant loss of performance of the turbomachine.

[0010] There is therefore a need to improve the cooling of the components of a recuperative cycle turbomachine located downstream of the gas generation. Summary of the invention

[0011] The invention offers a solution to the problems mentioned above, by making it possible to segregate the air serving as a cold source and the air serving as an oxidant before the latter is heated.

[0012] For this, the invention relates to an aircraft turbomachine comprising: • a compressor, configured to produce compressed air known as “fresh air”; • a diffuser, supplied with fresh air by the compressor; • a gas generation circuit, comprising: • a heat exchanger, configured to produce hot air from fresh air and supplied with fresh air by the diffuser; • a combustion chamber, configured to produce gas from hot air and supplied with hot air by the heat exchanger; and

[0013] a distributor, comprising: • an exhaust circuit, supplied with gas by the gas generation circuit; and • a cooling circuit called the “first cooling circuit”;

[0014] The turbomachine is remarkable in that it also comprises a fresh air distribution circuit, separate from the gas generation circuit and supplied with fresh air by the diffuser and in that the fresh air distribution circuit supplies fresh air to the first cooling circuit.

[0015] The turbomachine, comprising a heat exchanger, makes it possible to heat the air to be injected into the combustion chamber and thus improve the energy efficiency of the turbomachine.

[0016] Thanks to the distribution circuit, fresh air is conveyed to the distributor so as to cool it. The distribution circuit being separated from the gas generation circuit, no gas or hot air enters the first cooling circuit, making it possible to obtain cooling of the distributor at least equivalent to that of a conventional cycle turbomachine.

[0017] According to a variant of the invention, the fresh air distribution circuit comprises: • a first part called the "first distribution sub-circuit", supplied with fresh air by the diffuser and supplying fresh air to the first cooling circuit; and • a second part called the “second distribution sub-circuit”, arranged in continuity with the first distribution sub-circuit and supplied with fresh air by the first cooling circuit.

[0018] The first distribution sub-circuit is advantageously separated from the gas generation circuit by a first wall. The second distribution sub-circuit is also advantageously separated from the gas generation circuit by a second wall.

[0019] The turbomachine according to the invention may further comprise a turbine, said turbine comprising: • a turbine wheel; and • a turbine ring, surrounding the periphery of the turbine wheel and comprising a cooling circuit called the “second cooling circuit”.

[0020] The second cooling circuit is then advantageously supplied by the fresh air distribution circuit and preferably by the second distribution sub-circuit.

[0021] The turbomachine according to the invention also comprises a main axis of rotation. The fresh air distribution circuit then advantageously has an annular shape extending around the main axis of rotation.

[0022] According to another variant of the invention, the combustion chamber is inverted.

[0023] Another aspect of the invention also relates to a method of manufacturing a Aircraft turbomachine, comprising the installation of a first separating wall separating the first distribution sub-circuit from the gas generation circuit, and a second separating wall separating the second distribution sub-circuit from the gas generation circuit.

[0024] The method thus makes it possible to manufacture a recuperated cycle turbomachine showing cooling performance at least equivalent to that of a conventional cycle turbomachine.

[0025] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0026] The figures are presented for information purposes only and in no way limit the invention. Unless otherwise specified, the same element appearing in different figures has a single reference.

[0027] [Fig.l], already described, represents a conventional cycle turbomachine according to the prior art.

[0028] [Fig.2] schematically represents a turbomachine according to the invention.

[0029] [Fig.3] represents, according to a first section, flows of fresh air, hot air and gas in one embodiment of the turbomachine.

[0030] [Fig.4] structurally represents, according to the first section, the turbomachine of the [Fig.3].

[0031] [Fig.5] represents, in perspective, a distributor of the turbomachine of the [Fig.4],

[0032] [Fig.6] represents a detail of the turbomachine of [Fig.4]. DETAILED DESCRIPTION

[0033] An example of an aircraft turbomachine according to the invention will now be described.

[0034] [Fig.l] has already been described. The reference signs used to describe [Fig.l] are used to describe other figures provided that the elements to which they refer are equivalent or perform the same functions.

[0035] The terms "upstream" and "downstream" are defined relative to the direction of gas flow. produced by the turbomachine. The gas flows from upstream to downstream.

[0036] The turbomachine comprises a main axis of rotation. This is the axis around which major mechanical components such as a compressor or a turbine rotate. An example of a main axis of rotation A is shown on the turbomachine 1' according to the prior art in [Fig. 1].

[0037] By axially oriented is meant oriented parallel to the main axis of rotation to within ±10°, or even ±5°. By radially oriented is meant oriented perpendicular to the main axis of rotation to within ±10°, or even ±5°.

[0038] A first element is said to be "radially internal" or "internal" and a second element is said to be "radially external" or "external" when the first element is radially closer to the main axis of rotation than the second element.

[0039] A surface is said to be "radially internal" or "internal" when its normal is oriented towards the main axis of rotation. A surface is said to be "radially external" or "external" when, on the contrary, its normal is not oriented towards the main axis of rotation.

[0040] [Fig. 2] functionally represents an aircraft turbomachine 1 according to the invention. In this figure, the turbomachine 1 comprises a compressor 3. The compressor 3 is configured to produce fresh air. This is compressed air whose temperature is lower than the temperature of the gas produced by the turbomachine 1. The air is said to be "fresh" when its temperature is preferably lower than 750 K. For this purpose, the compressor 3 can be supplied by ambient air or from another compressor, as shown in [Fig. 1]. In the latter case, the compressor 3 is then called a "high-pressure compressor".

[0041] The turbomachine 1 also comprises a diffuser 4, also called a radial diffuser, supplied with fresh air by the compressor 3.

[0042] The turbomachine 1 further comprises a gas generation circuit 20. The gas generation circuit 20 is configured to produce gas from fresh air. For this, the gas generation circuit 20 comprises a heat exchanger 16 and a combustion chamber 6.

[0043] The heat exchanger 16 is configured to produce hot air from fresh air. It is in particular supplied with fresh air by the diffuser 4. The air is said to be hot when its temperature is preferably greater than or equal to 750 K, or even greater than or equal to 1000 K. The heat exchanger 16 comprises a primary circuit and a secondary circuit, not shown, in thermal contact with the primary circuit. The primary circuit is configured to circulate the fresh air to be heated. The secondary circuit is configured to circulate at least a portion of the gas from the generation circuit 20 and heat the fresh air. The temperature of the gas from the gas generation circuit 20 is for example greater than or equal to 1500 K.

[0044] The combustion chamber 6 is configured to produce gas from hot air from the heat exchanger 16. The combustion chamber 6 advantageously comprises a fuel injection system. The hot air thus constitutes an oxidant which, mixed with the fuel, makes it possible to feed a combustion reaction producing the gas.

[0045] The turbomachine 1 also comprises a distributor 7, also called a fixed-blade distributor. The distributor 7 is one of the first parts located downstream of the gas generation circuit 20. The distributor 7 is advantageously located between the gas generation circuit 20 and a means for converting the kinetic energy of the gas into mechanical energy, such as a turbine. The distributor 7 makes it possible to accelerate the gas from the gas generation circuit 20 before it reaches said energy conversion means. When the energy conversion means is a turbine, the distributor 7 also makes it possible to orient the gas so that it comes into contact with the turbine at an angle allowing the best energy conversion.

[0046] The distributor 7 comprises an exhaust circuit 72. Said exhaust circuit 72 is supplied with gas by the gas generation circuit 20. The distributor 7 also comprises a cooling circuit 73, called the "first cooling circuit". The first cooling circuit 73 is preferably configured to control the temperature of the distributor 7. The first cooling circuit 73 also makes it possible to exchange heat with the exhaust circuit 72 and consequently to cool the gas produced

[0047] The turbomachine 1 according to the invention is distinguished from a turbomachine 1' according to the prior art in that it comprises a fresh air distribution circuit 21. The fresh air distribution circuit 21 is configured to supply fresh air to the first cooling circuit 73. In this way, the distributor 7 cooled from fresh air is cooled with a performance at least equivalent to a conventional cycle turbomachine (i.e. without heated air) according to the prior art.

[0048] The fresh air distribution circuit 21 is separated from the gas generation circuit 20. By "separated from the gas generation circuit" is meant that there is no transfer of mass or matter between the two circuits. In other words, the fluids circulating in the gas generation circuit 20, comprising hot air and gas, or even fuel, do not circulate in the distribution circuit 21. The hot air therefore does not enter the first cooling circuit 73, avoiding heating of the distributor 7, or even its deterioration.

[0049] The separation of the fresh air distribution circuit 21 from the gas generation circuit 20 makes it possible to obtain cooling of the distributor 7 having a performance which can be superior to the cooling observed in a conventional cycle turbomachine (not involving air heating). Indeed, in a cycle turbomachine conventional, the fluid used in cooling the distributor 7 comes from the combustion chamber. A substantial portion of said fluid comprises fresh air having bypassed a flame tube and is therefore partially heated. In addition, a residual portion of said fluid may comprise gas having a high temperature. This mixture of partially heated air and hot gas constitutes a poor cold source and reduces the cooling efficiency of the distributor 7.

[0050] The fresh air distribution circuit 21 is supplied with fresh air by the diffuser 4. The circulating air is therefore obtained before it is heated by the heat exchanger 16. Therefore, the elements supplied by the distribution circuit 21 are supplied only with fresh air.

[0051] The fresh air distribution circuit 21 advantageously comprises a first part 18 called the "first distribution sub-circuit" and a second part 19 called the "second distribution sub-circuit". The first distribution sub-circuit 18 is supplied with fresh air by the diffuser 4. It supplies fresh air to the first cooling circuit 73. The second distribution sub-circuit 19 is supplied with fresh air by the first cooling circuit 73. The fresh air having circulated in the first cooling circuit 73 is then reused by the second distribution sub-circuit 19. In addition, the first cooling circuit 73 then makes the connection between the first and second distribution sub-circuits 18, 19. The second distribution sub-circuit 19 is thus in the continuity of the first distribution sub-circuit 18.

[0052] Each of the first and second distribution sub-circuits 18, 19 is separated from the gas generation circuit 20, advantageously by means of sealed walls.

[0053] The turbomachine 1 according to the invention advantageously comprises a means for converting the kinetic energy of the gas into mechanical energy. This is for example a turbine, comprising a turbine wheel 8. The turbine wheel 8 is a moving part comprising a blade. The gas passing through the turbine wheel 8 expands through the blade and causes the wheel 8 to rotate. The turbine wheel 8 is advantageously connected to a rotor so as to transmit the mechanical energy obtained from the expansion of the gas. The energy conversion efficiency requires that a substantial portion of the gas produced by the gas generation circuit 20 passes through the turbine wheel 8.

[0054] For this, the turbine then advantageously comprises a turbine ring 17. The turbine ring 17 surrounds the periphery of the turbine wheel so as to force the passage of the gas generated through the turbine wheel 8. A clearance 178 between the turbine wheel 8 and the turbine ring 17 allows the friction-free rotation of the turbine wheel 8. On the other hand, the clearance 178 implies a leak of gas not passing through the turbine wheel 8. The clearance 178 between the turbine wheel 8 and the turbine ring 17 depends on the thermal expansion of said ring 17 and therefore on its temperature. In order to ensure a controlled expansion of the turbine ring 17, the latter advantageously comprises a cooling circuit called "second cooling circuit".

[0055] According to a variant of the invention, the second cooling circuit 171 is supplied by the fresh air distribution circuit 21. Thus, the cooling of the turbine ring 17, also using fresh air, is efficient. The expansion of the turbine ring 17 is thus controlled and the efficiency of conversion of the kinetic energy of the gas is thus optimal.

[0056] The second cooling circuit 171 is preferably supplied by the second fresh air distribution sub-circuit 19. The fresh air having circulated in the first cooling circuit 73 is recovered and then also circulates in the second cooling circuit 171. A substantial part of the heat capacity of the fresh air is thus implemented.

[0057] [Fig.3], [Fig.4], [Fig.5] and [Fig.6] represent a common embodiment of the turbomachine 1 according to the invention. The characteristics described previously, with reference to [Fig.2] are applicable to the turbomachine 1 according to [Fig.3] to [Fig.6]. [Fig.6] represents in particular a detail of a portion C circled in [Fig.4].

[0058] [Fig. 3] shows, by means of arrows, the flow of fluids in the different circuits. The black arrows represent the flow of fresh air, in particular in the distribution circuit 21, the distributor 7 and the turbine ring 17. The hatched arrows represent the flow of air heated by means of the heat exchanger 16 and participating in the production of the gas. The dotted arrows represent the flow of the gas produced by the combustion of the heated air and ejected by the nozzle 11 after passing through the distributor 7 and the turbine wheel 8.

[0059] The embodiment of the turbomachine 1 is now described with reference to [Fig. 3] and [Fig. 4]. According to this embodiment, the compressor 3 is a centrifugal compressor. It is aligned along a main axis of rotation of the turbomachine 1. An example of a main axis of rotation A is shown on the turbomachine 1' according to the prior art in [Fig. 1]. The compressor 3 comprises an inlet oriented axially relative to the main axis of rotation and an outlet oriented radially relative to the main axis of rotation.

[0060] The diffuser 4 is advantageously a radial diffuser. It advantageously extends around the main axis of rotation. The diffuser 4 then comprises an inner edge, opposite the main axis of rotation, and an outer edge, radially opposite the inner edge. The diffuser 4 comprises, on its inner edge, an inlet, connected to the outlet of the compressor 3, so as to be supplied with fresh air by the compressor 3 (black arrows). Thus, the diffuser 4 converts the speed of the air from the centrifugal compressor 3 into pressure.

[0061] The diffuser 4 comprises, on its external edge, a first outlet connected to the heat exchanger 16, so as to supply fresh air to the gas generation circuit 20. According to this embodiment, the heat exchanger 16 comprises an inlet circuit 161 supplied with fresh air by the diffuser 4. It also comprises an outlet circuit 162 supplying the heated air (hatched arrows) to the combustion chamber 6. The primary and secondary circuits of the heat exchanger 16, allowing the air to be heated, are not shown in the figures.

[0062] The gas generation circuit 20 according to this embodiment also comprises an axial diffuser 5, also called a rectifier. The axial diffuser 5 is supplied with heated air by the heat exchanger 16 and supplies the combustion chamber 6 with heated air. It is preferably configured to straighten the flow of heated air from the heat exchanger 16 so that it enters the combustion chamber 6 while being oriented axially with the main axis of rotation. The axial diffuser 5 is advantageously supplied with heated air by the outlet circuit 162 of the heat exchanger 16 to which it is connected.

[0063] The combustion chamber 6 according to [Fig.3] and [Fig.4] forms an annular chamber extending around the main axis of rotation. It delimits an annular volume in which the combustion reaction between fuel and hot air takes place. Said annular volume comprises, on one of its radially external surfaces, a wall 62 called the "external casing". The combustion chamber 6 is supplied with heated air by the heat exchanger 16, and in particular by means of the axial diffuser 5. The combustion chamber 6 may comprise a flame tube 61 for containing the reaction front. The flame tube 61 is formed from a perforated sheet metal allowing the heated air to circulate. In this example, it also comprises an opening through which the fuel is injected. The gas resulting from the combustion of the heated air and the fuel is shown by the dotted arrows.The generated gas travels through the flame tube 61 before passing through the distributor 7, the energy conversion means and then being evacuated through a nozzle 11. The flame tube 61 advantageously has a spacing with each wall of the combustion chamber 6, including the external casing 62. In this way, the hot air injected into the combustion chamber 6 can envelop a part of the flame tube 61 and penetrate into the flame tube 61 uniformly, in order to improve the combustion reaction and therefore the generation of gas.

[0064] The combustion chamber 6, as shown, has a so-called "inverted" geometry, i.e. folded back on itself. An inverted combustion chamber 6 makes it possible to limit the total length of the turbomachine 1. It also makes it possible to constitute an additional protective barrier in the event of a disc rupture with ejection of fragments from the turbine wheel 8.

[0065] [Fig. 5] represents the distributor 7 of the turbomachine 1 according to the embodiment of [Fig. 3] and [Fig. 4]. The distributor 7 has an annular shape extending around an axis B. The axis B advantageously extends, when the distributor 7 is assembled in the turbomachine 1, along the main axis of rotation. The exhaust circuit 72 of the distributor 7 is oriented parallel to the axis B. The exhaust circuit 72 comprises a plurality of fixed blades, distributed radially around the axis B, and forming the walls of a plurality of conduits within which the exhaust gas can flow. The flow of the gas, in contact with the fixed blades, is thus oriented and cooled.

[0066] The first cooling circuit 73 of the distributor 7 is, for example, oriented radially relative to the axis B. The cooling circuit 73 also comprises a plurality of inserts allowing the passage of fresh air. Each insert is advantageously arranged in a hollow blade allowing the passage of fresh air within it. Each blade thus performs the function of a heat exchanger, allowing the gas flowing over its outer walls to be cooled by the fresh air flowing within it.

[0067] Each insert of the first cooling circuit 73 may also comprise at least one opening, passing through an outer wall of each blade, connecting said insert with the exhaust circuit 72. Thus, a stream of fresh air circulating in the first cooling circuit 73 mixes with the gas from the generation circuit 20 and further reduces its temperature. The stream of fresh air from the first cooling circuit 73 also makes it possible to control the external temperature of each blade and thus reduces the risk of thermal degradation of the distributor 7.

[0068] The combustion chamber 6, represented by [Fig.3] and [Fig.4], comprises an outlet connected to the exhaust circuit 72 of the distributor 7, allowing the gas to be cooled before it reaches the turbine wheel 8.

[0069] The flow of fresh air in the turbomachine 1 according to the invention, represented by the black arrows, can be seen in [Fig. 3]. A portion of the fresh air enters the inlet circuit 161 of the heat exchanger 16. Another portion enters the fresh air distribution circuit 21 in order to circulate in the distributor 7 and at the turbine ring 17.

[0070] The first distribution sub-circuit 18 according to the embodiment of [Fig.3] and [Fig.4] is formed by a first separating wall 181 and a second wall 182 delimiting an annular volume extending around the main axis of rotation. The first separating wall 181 extends over a radially external edge of the annular volume and the second wall 182, called the "internal casing", extends over a radially internal edge of the annular volume. The internal casing 182 advantageously belongs to the surfaces delimiting the combustion chamber 6' of a turbomachine according to the prior art, i.e. without a distribution circuit 21. The first separating wall 181 separates the first distribution sub-circuit 18 from the generation circuit of gas 20 and more particularly of the combustion chamber 6 according to the invention. A first surface of the first separating wall 181 faces the annular volume of the first distribution sub-circuit 18. A second surface of the first separating wall 181 faces at least part of the gas generation circuit 20, for example of the combustion chamber 6.

[0071] The first separating wall 181 extends from the diffuser 4 to the distributor 7. It more particularly connects the distributor 7 so as to separate the inlet of the exhaust circuit 72 and the inlet of the first cooling circuit 73. Thus, only the gas circulates in the exhaust circuit 72 and only the fresh air circulates in the first cooling circuit 73.

[0072] The first separating wall 181 preferentially connects the diffuser 4 at an outlet so as to collect a portion of the fresh air supplying the heat exchanger 16. The diffuser 4 comprises for example a first outlet 41, configured to supply the heat exchanger 16, and a second outlet 42, configured to supply fresh air to the first distribution sub-circuit 18. The first separating wall 181 then preferentially connects the diffuser 4 so as to separate the first outlet 41 and the second outlet 42. The first outlet 41 is for example oriented radially relative to the main axis of rotation and the second outlet 42 is for example oriented axially relative to the main axis of rotation. The first separating wall 181 then advantageously connects the outer edge of the diffuser 4.

[0073] The structural simplicity of the first distribution sub-circuit 18, and in particular its first separating wall 181, makes it possible to simply modify a turbomachine 1' according to the prior art so as to form a first distribution sub-circuit 18 according to the invention and thus improve the cooling of the distributor 7. Indeed, in a turbomachine according to the prior art, the combustion chamber 6' is delimited by a wall assembly comprising in particular an outer casing and the inner casing 182, the outer and inner casings 182 being radially opposed. The first distribution sub-circuit 18 according to the invention and the combustion chamber 6' according to the prior art share the inner casing 182.Thus, a method of manufacturing a turbomachine according to the invention provides for the separation of the volume of the combustion chamber 6' according to the prior art into two sub-volumes making it possible to form the combustion chamber 6 according to the invention and the first distribution sub-circuit 18 according to the invention. Said separation is advantageously achieved by the addition of the first separation wall 181 according to the characteristics described previously in the combustion chamber 6' according to the prior art.

[0074] According to the embodiment of [Fig.3] to [Fig.6], the energy conversion means of the turbomachine 1 is formed by the turbine wheel 8 and the turbine ring 17 such as described previously.

[0075] [Fig. 6] represents a detail centered on a portion C of the turbomachine 1, materialized by a dotted line circle in [Fig. 4]. [Fig. 6] shows in particular the distributor 7, the turbine wheel 8 and the turbine ring 17. [Fig. 6] also shows, by means of arrows, the flow of fresh air in the fresh air distribution circuit 18, 19, the distributor 7 and the turbine wheel 8. The turbine wheel 8 is located downstream of the distributor 7 to convert part of the kinetic energy of the gas from the generation circuit 20 into mechanical energy. The turbine wheel 8 is crossed in particular by the gas from the exhaust circuit 72 of the distributor 7. The gas is cooled and oriented by the blades of the distributor 7 so that the angle of attack of the gas on the turbine wheel 8 allows efficient energy conversion. The gas having passed through the turbine wheel 8 is then directed into a nozzle 11.

[0076] The turbine wheel 8 has an axis which advantageously merges with the main rotation axis of the turbomachine 1. The turbine ring 17 in this embodiment also has an annular shape, advantageously extending around the main rotation axis. The ring 17 is adapted to cooperate with the turbine wheel 8 while allowing mechanical clearance. It advantageously comprises an abradable material 172 on a radially internal part. The abradable material 172 allows contact of the turbine wheel 8 on the ring 17 when the mechanical clearance between said turbine wheel 8 and the ring 17 is too small, for example when the ring 17 is cold and contracted. The second cooling circuit 171 of the turbine ring 17 is for example configured to allow forced convection of a fluid within it. It has for example a cavity allowing a heat transfer fluid to circulate.The ring cavity 17 may also include radially oriented openings through which the heat transfer fluid may flow. Forced convection in the ring cavity 17 may also implement jet impingement cooling. For example, openings 1710 in the cooling system may be provided to create and direct jets of fluid toward the abradable material 172.

[0077] The second distribution sub-circuit 19 according to the embodiment of [Fig.3], [Fig.4] and [Fig.6] is separated from the gas generation circuit 20, and in particular from the combustion chamber 6, by a second separating wall 191. The second separating wall 191 delimits, with the turbine ring 17, an annular volume extending around the main axis of rotation and belonging to the second distribution sub-circuit 19. The second separating wall 191 extends over a radially external edge of said annular volume while the turbine ring 17 extends over a radially internal edge of said annular volume.

[0078] A first surface of the second partition wall 191 faces the annular volume of the second distribution sub-circuit 19. A second surface of the second partition wall 191 is opposite at least part of the gas generation circuit 20, for example, the combustion chamber 6.

[0079] The second separating wall 191 advantageously connects the distributor 7 so as to separate the exhaust circuit 72 and the first cooling circuit 73. Thus, only the fresh air leaving the first cooling circuit 73 circulates in the second distribution sub-circuit 19. The second separating wall 191 also connects the turbine ring 17 so that the second cooling circuit 171 is only supplied with fresh air by the second distribution sub-circuit 19.

[0080] The second separating wall 191 can also connect the walls of the combustion chamber 6 so as to create a closed cavity connecting the first cooling circuit 73 with the second cooling circuit 171.

[0081] The invention makes it possible to modify a turbomachine 1' according to the prior art so as to form a second distribution sub-circuit 19 and thus improve the cooling of the turbine ring 17. Indeed, in a turbomachine 1' according to the prior art, the first and second cooling circuits 73, 171 are supplied from heated air, coming from the combustion chamber 6' according to the prior art. The method for manufacturing a turbomachine 1' according to the invention then also provides for the separation of the combustion chamber 6' according to the prior art into two complementary sub-volumes so as to form the second fresh air distribution sub-circuit 19 and the combustion chamber 6 according to the invention.The method then advantageously comprises The step of adding the first separation wall 181 then also comprises the addition of the second separation wall 191 according to the characteristics described previously in the combustion chamber 6' according to the prior art.

[0082] The second sub-circuit, the fresh air distribution circuit 19, is preferably supplied with fresh air by the first cooling circuit 73. The air from the first cooling circuit 73 of the distributor 7 may be hotter than the fresh air circulating in the first distribution sub-circuit 18. On the other hand, it advantageously has a low temperature, for example less than 750 K, thus constituting a sufficient cold source to regulate the temperature of the turbine ring 17.

[0083] A cooling circuit for the turbine wheel 8, called an "auxiliary cooling circuit", makes it possible to circulate fresh air at the turbine wheel 8 and in each blade of said wheel 8, allowing effective cooling of the latter. The first distribution sub-circuit 18 may then also comprise, at the internal casing 182, a plurality of first openings 183, as illustrated in [Fig. 6], configured to allow a portion of the fresh air circulating within said first sub-circuit 18 to escape and supply the auxiliary cooling circuit.

[0084] The first distribution sub-circuit 18 may also comprise at the level of the first partition wall 181, a plurality of second openings 184, as illustrated in [Fig.6]. Each second opening 184 is preferably opposite the first cooling circuit 73 and makes it possible to supply fresh air to the latter. The dimensions and the number of second openings 184 are advantageously chosen to adjust the quantity of fresh air escaping towards the auxiliary cooling circuit of the turbine wheel 8 and the quantity of fresh air entering the first cooling circuit 73.

Claims

Claims

1. Aircraft turbomachine (1) comprising: - a compressor (3), configured to produce compressed air called "fresh air"; - a diffuser (4), supplied with fresh air by the compressor (3); - a gas generation circuit (20), comprising: - a heat exchanger (16), configured to produce hot air from fresh air and supplied with fresh air by the diffuser (4); - a combustion chamber (6), configured to produce gas from hot air and supplied with hot air by the heat exchanger (16); - a distributor (7), comprising: - an exhaust circuit (72), supplied with gas by the gas generation circuit (20); and - a cooling circuit (73) called "first cooling circuit";the turbomachine (1) being characterized in that it also comprises a fresh air distribution circuit (21), separate from the gas generation circuit (20) and supplied with fresh air by the diffuser (4) and in that the fresh air distribution circuit (21) supplies fresh air to the first cooling circuit (73).;

2. Turbomachine (1) according to the preceding claim, characterized in that the fresh air distribution circuit (21) comprises: - a first part (18) called "first distribution sub-circuit", supplied with fresh air by the diffuser (4) and supplying fresh air to the first cooling circuit (73); and - a second part (19) called "second distribution sub-circuit", arranged in the continuity of the first distribution sub-circuit (18) and supplied with fresh air by the first cooling circuit (73).

3. Turbomachine (1) according to the preceding claim, characterized in that the first distribution sub-circuit (18) is separated from the distribution circuit gas generation (20) by a first separating wall (181) and in that the second distribution sub-circuit (19) is separated from the gas generation circuit (20) by a second separating wall (191).

4. Turbomachine (1) according to one of the preceding claims, characterized in that it comprises a turbine (8, 17) comprising: - a turbine wheel (8); and - a turbine ring (17), surrounding the periphery of the turbine wheel (8) and comprising a cooling circuit (171) called "second cooling circuit"; the second cooling circuit (171) being supplied by the fresh air distribution circuit (21).

5. Turbomachine (1) according to the preceding claim and one of claims 2 or 3, characterized in that the second cooling circuit (171) is supplied by the second fresh air distribution sub-circuit (19).

6. Turbomachine (1) according to one of the preceding claims, characterized in that it comprises a main axis of rotation (A), the fresh air distribution circuit (21) having an annular shape extending around the main axis of rotation (A).

7. Turbomachine (1) according to one of the preceding claims, characterized in that the combustion chamber (6) is inverted.

8. Method for manufacturing an aircraft turbomachine (1), comprising a gas generation circuit (20), said method comprising the installation of a first separating wall (181) separating a first distribution sub-circuit (18) from the gas generation circuit (20), and a second separating wall (191) separating a second distribution sub-circuit (19) from the gas generation circuit (20).

Images