Three-flow axial turbine engine with sealed heat exchanger in third flow

Abstract

The invention relates to a turbomachine comprising: a first separation lip capable of separating an incoming air flow into a radially inner air flow and a secondary air flow; a second separation lip capable of separating the radially inner air flow into a main flow and a tertiary flow, the tertiary flow flowing through a tertiary flow passage, the tertiary flow passage being radially outer of a main flow passage through which the main flow passes; a heat exchanger (18) arranged in the third-stage flow channel; and an inner housing (28); notably, the exchanger comprises an upstream portion (50) comprising a collar (52) extending upstream from the body (32) of the exchanger in a protruding manner, said collar being housed in a floating manner in a groove (54) extending circumferentially in the inner housing.

Description

Technical Field

[0001] The present invention relates to the field of turbines, more particularly to three-flow turbines. The present invention relates to the arrangement of a heat exchanger for cooling the oil of a turbine. Background Art

[0002] Climate change is a major concern for many legislative and regulatory bodies around the world. In fact, states have, are or will adopt various limits on carbon emissions. In particular, stringent standards apply not only to new aircraft, but also to those already in circulation that require the implementation of technical solutions to make them compliant with current regulations. Civil aviation has been mobilizing for many years to contribute to the fight against climate change.

[0003] The results of technological research have made it possible to significantly improve the environmental performance of aircraft. The applicant has taken into account influencing factors at all stages of design and development in order to obtain aviation components and products with lower energy consumption and more environmentally friendly, whose integration and use in civil aviation have a moderate environmental impact, with the aim of improving the energy efficiency of aircraft.

[0004] Therefore, Applicant is continuously working to reduce the negative climate impact of greenhouse gases by using a variety of methods, operating benign development and manufacturing processes, and reducing greenhouse gas emissions to the lowest possible level to reduce the environmental footprint of greenhouse gas emitting activities.

[0005] This ongoing research and development work covers new generation aircraft engines, reduction of aircraft weight (particularly through the materials used and lighter onboard equipment), developments in the use of electrical technology to provide propulsion, and aviation biofuels as a necessary complement to technological advances.

[0006] In this context, the invention relates more specifically to aspects related to the arrangement of heat exchangers in turbomachines. In fact, in turbomachines, it is often necessary to cool the oil of the lubrication circuit. It is known to arrange one or more heat exchangers in the tertiary flow of a three-flow turbomachine, that is to say in the radial intermediate flow between the main flow leading to the combustion chamber and the secondary outer flow.

[0007] Integration of the exchanger in the tertiary flow (constrained between the primary and secondary flows) creates difficulties in assembly and accessibility in the event of maintenance, but also creates limitations related to sealing in operation due to the thermal expansion of the exchanger. The "brick" type exchangers inspired by document FR 3 089 248 A1 do not meet these limitations and are therefore not suitable for the tertiary flow.

[0008] Therefore, integrating an exchanger into the third flow of a three-flow turbine raises challenges related to the size of the exchanger, the assembly of the exchanger, the accessibility of the exchanger, the operation of the exchanger and the overall mass of the means for fixing the exchanger to the casing. Summary of the invention

[0009] Technical issues

[0010] The present invention aims to overcome at least one of the above-mentioned disadvantages of the prior art. More specifically, the present invention aims to propose a simple, effective and economical solution to the disadvantages of the design / manufacture of the turbines of the prior art. In particular, the present invention aims to propose a solution that enables effective cooling in a confined space while ensuring accessibility of the heat exchanger during maintenance operations and ensuring proper sealing and safety of the turbine in case of fire, but also without adding weight and without interfering with the performance of the turbine.

[0011] Technical Solution

[0012] To this end, the present invention relates to a turbine comprising:

[0013] a first separation lip capable of separating the incoming air flow into a radially inner air flow and a radially outer air flow, the latter being called the secondary flow;

[0014] - a second separation lip capable of separating the radially inner air flow into a main flow and a tertiary flow, the tertiary flow flowing through a tertiary flow channel, the tertiary flow channel being radially outside the main flow channel passed through by the main flow;

[0015] - a heat exchanger arranged in the tertiary flow channel; and

[0016] - inner housing;

[0017] The turbine is characterized by:

[0018] The heat exchanger includes a body and a flange, which extends radially inward and protrudes from the body, and the flange is fixed to the inner shell. The heat exchanger also includes an upstream part upstream of the flange, which upstream part includes a shaft ring protruding and extending upstream from the body of the heat exchanger, and the shaft ring is accommodated in a groove in a floating manner, which extends circumferentially in the inner shell.

[0019] Advantageously, the collar is mounted in the groove without any fixing and avoids mechanical stress areas when the heat exchanger undergoes thermal expansion. To this end, the floating mounting of the collar in the groove allows expansion deformation in the axial, radial and circumferential directions.

[0020] Preferably, the downstream portion of the heat exchanger comprises a circumferentially extending groove, and the turbine further comprises an inner ring of the tertiary flow channel, the inner ring comprising an upstream portion received in the groove.

[0021] Preferably, the inner ferrule and the inner casing correspond to the inter-blade fairings of the turbine, which are arranged between the primary flow channel and the tertiary flow channel. Advantageously, the casing and the inner ferrule are aerodynamically continuous with the tertiary flow channel, and preferably, the casing and the inner ferrule constitute the radial inner guide wall of the tertiary flow.

[0022] Advantageously, the mounting of the upstream part of the ferrule in the groove is floating and without any fixing. This avoids the generation of mechanical stress areas when the heat exchanger undergoes thermal expansion. For this reason, expansion deformation is possible in the axial direction, the radial direction and the circumferential direction.

[0023] According to an advantageous embodiment of the invention, the fixing flange extends circumferentially over at most 50% of the circumferential extent of the heat exchanger.

[0024] According to an advantageous embodiment of the invention, the fixing flange is arranged in the central position of the heat exchanger in the circumferential direction.

[0025] Advantageously, the flange is circumferentially centered on the heat exchanger, the flange enabling free expansion of the heat exchanger by allowing the heat exchanger to extend tangentially in the third flow channel.

[0026] According to an advantageous embodiment of the invention, the flange is fixed to the housing by means of fixing elements enabling blind fixing.

[0027] In this configuration, the heat exchanger is advantageously mounted directly in the recess of the inner casing, this mounting being carried out from downstream to upstream and by simple insertion, thus facilitating the accessibility and maintainability of the heat exchanger.

[0028] According to an advantageous embodiment of the invention, the turbomachine comprises a first thermal insulation seal which is arranged in the groove and is inserted between the housing and the heat exchanger.

[0029] The seal ensures sealing between the heat exchanger and the inner casing to avoid air leakage in the blade compartments while avoiding the addition of fixing elements for the upstream portion of the heat exchanger to the casing, the purpose of which is to rigidify the heat exchanger and prevent it from deforming.

[0030] Preferably, the turbine comprises a second heat insulation seal which is arranged in the groove and inserted between the heat exchanger housing and the collar.

[0031] The second seal limits the deformation of the ferrule due to the heat conduction of the ferrule with the heat exchanger. Thus, the second seal eliminates the need for a fixing element of the ferrule to the housing, which is intended to rigidify the ferrule and prevent deformation of the ferrule.

[0032] According to an advantageous embodiment of the invention, the turbine comprises structural arms extending radially through the tertiary flow channel and defining inter-arm spaces between the structural arms, the turbine comprising a heat exchanger in each inter-arm space, each of the heat exchangers comprising a body and a flange extending radially inwardly and protruding from the corresponding body, each flange being fixed to the inner casing, each of the heat exchangers further comprising a transverse insulation seal interposed between the heat exchanger and an adjacent structural arm.

[0033] In this configuration, the transverse seals are able to ensure the sealing of the heat exchanger in the flow channel in the circumferential direction, in particular during the contraction of the exchanger after expansion in the inter-blade space. The transverse seals make it possible to absorb the circumferential play between the exchanger and the structural arm, so that the seals always remain in contact and sealed with the structural arm.

[0034] According to an advantageous embodiment of the invention, each of the exchangers comprises a first seal and two transverse insulating seals formed integrally with the first seal.To this end, the first seal together with the structural arms ensures sealing and insulation for 360° around the longitudinal axis.

[0035] Preferably, the second insulating seal is common to all the exchangers and is interposed between the exchanger and the ferrule. Advantageously, the second seal ensures sealing and thermal insulation over 360° around the longitudinal axis.

[0036] According to an advantageous embodiment of the invention, the flange is arranged in the downstream half of the exchanger, downstream of said flange the exchanger also comprising a downstream portion to which a fire wall forming a heat shield is attached.

[0037] Preferably, the axial length of the downstream portion is between 20% and 50% of the axial length of the exchanger. This facilitates assembly / disassembly from the downstream side, as the flange is easily accessible without mechanically unbalancing the cantilever mounting of the downstream portion of the exchanger.

[0038] Advantageously, the fire wall corresponds to a fire-resistant wall that delays the propagation of a latent fire from the main flow path (for example, from the combustion chamber) to the rest of the aircraft (to the aircraft cabin). Attaching the fire wall to the exchanger enables the overall volume to be reduced, but also facilitates the maintenance of these elements, since no additional fixing of the fire wall is required.

[0039] The invention also relates to a method for removing a heat exchanger in a turbomachine according to one of the advantageous embodiments of the invention described above, the method comprising the following steps:

[0040] - dismantling the fixing elements of the flange to the housing;

[0041] - Removal of the exchanger by axial displacement towards the downstream side.

[0042] Advantageously, removal of the exchanger is facilitated in part by a collar that floats in a groove and requires only a simple manual withdrawal towards the downstream side.

[0043] The invention also relates to a method for installing a heat exchanger in a turbomachine according to one of the advantageous embodiments of the invention described above, the method comprising the following steps:

[0044] - Mounting of the exchanger by axial displacement towards the upstream side;

[0045] - Fixing elements of the flange to the housing.

[0046] Advantages of the present invention

[0047] The heat exchanger, in addition to being able to cool the oil effectively by exchanging heat with the air, also ensures additional functions, such as the arrangement of the firewall, while ensuring the formation of the support of the seal and the collar. In this configuration, the number of intermediate parts introduced to meet the different required functions is significantly reduced, thereby reducing the mass and manufacturing costs of the turbine of the invention. For this reason, the assembly and disassembly of the heat exchanger are facilitated, thereby improving the maintainability of the turbine.

[0048] Furthermore, the invention is particularly advantageous because the positioning of the heat exchanger at the tertiary flow passage avoids interfering with the performance of the engine. This results in optimized energy efficiency and thrust, which advantageously enables a reduction in fuel consumption and greenhouse gas emissions, thereby reducing the environmental impact of the aircraft.

[0049] It should be understood that every detail of the following embodiments can be combined with every other detail of the other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] [ Figure 1 ] shows a longitudinal cross-sectional view of a turbine according to the invention, the turbine comprising a heat exchanger in a tertiary flow channel;

[0051] [ Figure 2 ] shows Figure 1 A front view of a three-stage flow passage including a plurality of heat exchangers;

[0052] [ Figure 3] shows a cross-sectional view of the mounting of the exchanger on the inner housing and the mounting of the inner shell on said exchanger;

[0053] [ Figure 4 ] shows a perspective view of an exchanger including an insulating gasket. DETAILED DESCRIPTION

[0054] In the following description, the terms "inboard" and "outboard" refer to the positioning relative to the longitudinal axis of rotation of the turbine. The axial direction corresponds to the direction along the longitudinal axis of rotation of the turbine. The radial direction is perpendicular to the longitudinal axis. Upstream and downstream refer to the flow direction of the flow in the turbine.

[0055] The accompanying drawings schematically illustrate components and are not drawn to scale. In particular, some dimensions are exaggerated to facilitate reading of the drawings.

[0056] Figure 1 A turbomachine 2 is shown, comprising a propeller 4 fixed to a hub 6 , which rotates about a longitudinal axis 8 .

[0057] The turbine 2 moves in an air flow F, the movement of which relative to the turbine 2 is caused by the rotation of the propeller 4 and by the advancement of the aircraft on which the turbine 2 is mounted.

[0058] The air flow F is separated by the first separation lip 10 into a radially inner air flow F′ and a radially outer air flow F2 (referred to as a secondary flow F2 ). The propeller 4 may be arranged upstream or downstream of the first separation lip 10 .

[0059] The radially inner air flow F′ passes through a moving wheel 12 which directs it towards a second separating lip 14 capable of separating it into a primary flow F1 and a tertiary flow F3 different from the secondary flow F2 .

[0060] The first separating lip 10 comprises an inner wall forming a first outer guide wall 11 for the radially inner air flow F′, said first outer guide wall 11 forming a convex profile visible from said radially inner air flow F′.

[0061] The second separation lip 14 comprises an outer wall which forms a second outer guide wall 13 of the radially inner air flow F' which has passed the moving wheel 12, said second outer guide wall 13 forming a convex profile visible from the tertiary flow F3. To this end, the second outer guide wall 13 corresponds to the radially inner guide wall 13 of the tertiary flow F3.

[0062] The tertiary flow F3 enters a tertiary flow passage 16 which is radially outside the main flow F1 and passes through a heat exchanger 18 arranged in the tertiary flow passage 16 .

[0063] The heat exchanger 18 extends radially and axially in the tertiary flow channel 16 , preferably in an upstream section 20 of the tertiary flow channel 16 , which upstream section has a longitudinal section that branches off in the flow direction of the tertiary flow F3 .

[0064] A heat exchanger 18 is arranged substantially axially between the high-pressure compressor 15 and a low-pressure compressor 17 , referred to as a “boost” 17 , at right angles to the inter-compressor housing.

[0065] The high-pressure compressor 15 and the low-pressure compressor 17 comprise rotating blades and straightener blades arranged in a main flow channel 21 traversed by the main flow F1 which advances towards a combustion chamber 23 .

[0066] A "Variable Bleed Valve (VBV)" passage 19 opens into the tertiary flow passage 16 axially downstream of the heat exchanger 18. The "Variable Bleed Valve" passage 19 provides a bleed function by returning a portion of the main flow F1 to the tertiary flow F3 to prevent the high pressure compressor 15 from becoming blocked when the flow of the main flow F1 becomes too low.

[0067] The heat exchanger 18 may extend continuously over 360° around the longitudinal axis 8 of the turbine 2 in the upstream section 20 of the flow channel 16. Preferably, the turbine 2 comprises a plurality of heat exchangers 18 extending in the tertiary flow channel 16 and angularly subdividing the flow channel over 360° around the longitudinal axis 8 in a discontinuous manner. Each of the exchangers may independently provide a heat exchange function between air and fluid.

[0068] A single heat exchanger 18 can combine the cooling of several functions or oil circuits of the turbine, depending on the different parameters associated with the need to cool the oil (i.e. inlet temperature, flow rate, required outlet temperature or air conditions), either with the various circuits in thermal contact or well insulated. The exchanger 18, and in particular the oil channels of the exchanger 18, can withstand low oil temperatures of up to -54°C.

[0069] The upstream section 20 of the tertiary flow channel 16 comprises an outer flow guide 24 and an inter-channel fairing 26, at least one of which is rigidly connected to the exchanger 18. Preferably, the inter-channel fairing 26 is fixed to the exchanger 18. Such fixing will be described in detail later in this specification.

[0070] The inter-flow fairing 26 comprises an inner casing 28 arranged axially between the high-pressure compressor 15 and the low-pressure compressor 17, and also comprises an inner shell 30 arranged downstream of the exchanger 18. In this configuration, the inner casing 28 and the inner shell 30 together with the exchanger 18 constitute the radially inner guide wall of the tertiary flow F3.

[0071] Figure 2 yes Figure 1 1 is a front view (ie, in the direction opposite to the air flow) of a tertiary flow channel 16 including a plurality of heat exchangers 18. It can be seen that the exchangers 18 are distributed in the tertiary flow channel 16 at an angle.

[0072] The turbine 2 comprises structural arms 34 extending radially through the tertiary flow channel 16 and defining between them inter-arm spaces 36. Preferably, the turbine 2 comprises between 2 and 20 structural arms 34.

[0073] At the same time, the inner ferrule may be a single piece and circumferentially continuous over 360°, or the ferrule may be subdivided into multiple inner ferrules of up to 5 ferrules.

[0074] Preferably, the exchanger 18 is obtained by additive manufacturing, said exchanger 18 extending circumferentially between two structural arms 34 in each inter-arm space 36 .

[0075] The exchanger 18 comprises heat exchange surfaces 38 corresponding to the oil channels and / or heat exchange surfaces for air extending radially and axially in the inter-arm spaces 36. Examples of possible designs are described in detail in patent applications BE2021 / 5978, BE2021 / 5979, BE2021 / 5980, BE2021 / 5982 and BE2021 / 5983, the design of the heat exchange surfaces 38 or of the inner oil channels not being central to the present invention.

[0076] The exchanger 18 comprises a body 32 having a flange 32.1 extending radially inwards and protruding from said body 32, such that the flange 32.1 is fixed to an annular flange 28.1 belonging to the inner casing 28. Preferably, said annular flange 28.1 is continuous over 360° around the longitudinal axis of the turbine, whereas preferably the flange 32.1 of the exchanger 18 has a limited extent: the flange 32.1 is centered in the circumferential direction relative to the body 32. This advantageously enables the exchanger 18 to expand freely thermally by enabling it to extend tangentially in the inter-arm space 36.

[0077] Preferably, the assembly direction of the exchanger 18 in the turbine is from downstream to upstream. In this configuration, the fixing of the exchanger 18 to the inner casing 28 can be ensured by a threaded connection. Thus, the flange 32.1 can be fixed to the annular flange 28.1 by two to six screws and / or bolts 33, more preferably by three screws 33.

[0078] Preferably, three screws 33 are grouped circumferentially to embed the flange 32 . 1 in the center of the exchanger 18 , thereby tangentially releasing at least 50% of the circumferential extent of said exchanger 18 .

[0079] The exchanger 18 also comprises a downstream portion 40, which is arranged downstream of the flange 32.1 and is therefore mounted in a cantilevered manner. This downstream portion 40 has an inner surface with an inner contour 40.1, for example cylindrical or conical, around the longitudinal axis of the turbine, and a downstream surface with a downstream contour 40.2 substantially perpendicular to the longitudinal axis. Alternatively, the shape of the downstream portion 40 can be more free, as suggested by document EP 3 674 531 A1.

[0080] Preferably, the downstream surface 40 . 2 of the exchanger 18 comprises an oil inlet 42 at an angular end of the body 32 and an oil outlet 44 at a circumferentially opposite end.

[0081] The oil inlet 42 and the oil outlet 44 are fluidly connected to an oil collector and oil distributor, which are arranged in an inner portion (not shown) of the body 32 of the exchanger 18. Preferably, the inner portion of the body 32 may be hollow and free of material (except for the oil collector and distributor and the fluid connections) to make the exchanger 18 light.

[0082] The downstream portion 40 also comprises a groove 48 on its downstream surface 40.2, which extends circumferentially over the entire circumferential extent of the downstream portion 40. This allows Figure 1 The inner shell 30 of the inter-flow fairing 26 is supported by the exchanger 18 .

[0083] Figure 3 A cross-sectional view of the mounting of the exchanger 18 on the inner casing 28 and of the mounting of the inner shell 30 on said exchanger 18 is shown.

[0084] As can be seen, the exchanger comprises an upstream portion 50 having a collar 52 extending upstream from the body 32 of the exchanger 18, the collar 52 being housed in a floating manner and without any fixings in a groove 54 extending circumferentially in the inner casing 28. The collar 52 can be described as part of a ring with a constant radius relative to the axis 8 of the turbine. Alternatively, the radius of the collar 52 can vary and the groove 54 can have a corresponding profile in order to index the exchanger angularly during its assembly.

[0085] Advantageously, the collar 52 is arranged substantially flush with the radially inner guide wall 13, so as to follow Figure 1 Aerodynamic lines 16 . 1 of the air flow in the tertiary flow channel 16 are shown.

[0086] In this configuration, the exchanger 18 can be blindly fixed to the inner casing 28 of the turbine. Published patent document EP 3441 579 A1 discloses an example of a blind mounting on a turbine that can be used here.

[0087] Blind fixing can be ingenious, since the exchanger 18 is mounted in such a way that it is displaced axially upstream until the collar 52 is inserted into the groove 54 and until the upstream flange 28.1 comes into contact with the flange 32.1. Thus, there is no access from upstream to hold the nut immobile with a tool, and blind mounting makes it possible to overcome design limitations on the upstream side.

[0088] The turbomachine comprises a first thermal insulation seal 56 arranged in the groove 54 and interposed between the casing 28 and the exchanger 18 .

[0089] exist Figure 3 We can also see in FIG. 3 that the upstream portion 30 . 1 of the shell 30 is inserted into the groove 48 . In this configuration, a second insulating seal 58 is arranged in the groove 48 and is inserted between the shell 30 and the exchanger 18 .

[0090] Preferably, the first seal 56 and the second seal 58 are made of polyimide. DuPont TM Advantageously, the polyimide It is crack-resistant at very high temperatures, has excellent friction and wear characteristics, and does not produce significant gas evolution even at high temperatures.

[0091] Advantageously, the first seal 56 and the second seal 58 have elastic mechanical properties, enabling them to absorb part of the thermal expansion of the exchanger 18 in the axial and radial directions so as to avoid the propagation of mechanical stresses towards the casing 28 and the shell 30 and prevent any risk of deformation and / or rupture.

[0092] exist Figure 2 In the configuration shown, a first seal 56 and a second seal 58 are inserted between the exchanger 18 and the housing 28 and between the inner shell 30 and said exchanger 18 , respectively.

[0093] The mounting of the ferrule 30 in the groove 48 is a floating mounting without any fixing, so that in the event of thermal expansion of the exchanger 18 the ferrule 30 is protected from any deformation by expansion of the groove 48 in the axial, radial and circumferential directions.

[0094] Furthermore, the sealing of the assembly of the shell 30 and the exchanger 18 is ensured. This makes it possible to avoid Figure 1 There is no risk of air leakage from the flow channel compartment 27.

[0095] In this configuration and with reference to Figure 1 and Figure 3The exchanger 18 can be easily removed by opening the outer fairings 24 and opening the inter-channel fairings 26, by disassembling the shell 30, preferably by axially shifting it downstream, so that the pipes connected to the exchanger 18 can be removed. At this stage, the fixing screws of the flange 32.1 on the shell 28 can be removed and the exchanger 18 can be moved axially downstream by manual removal.

[0096] Advantageously, the disengagement of the collar 52 from the groove 56 is simple, since the mounting of the collar 52 to the groove 56 is carried out in a floating manner and without additional fixing.

[0097] Preferably, the exchanger 18 also comprises, at the downstream portion 40 , a fire wall 46 forming a heat shield, making it possible to delay the propagation of a possible fire from the main flow channel to the rest of the turbine.

[0098] Fire wall 46 can match the inner profile 40.1 and the downstream profile 40.2 of downstream portion 40 and can also extend radially to flange 32.1 and up to groove 48. Advantageously, in addition to protecting the turbine from the spread of fire, fire wall 46 can also protect shell 30 from the high temperatures of exchanger 18.

[0099] Preferably, the fire wall 46 corresponds to a layer of heat-insulating material such as high-performance plastic. More preferably, the fire wall 46 is made of polyimide. Similar to the joints 56 , 58 .

[0100] Figure 4 A perspective view of an exchanger 18 is shown including a transverse insulating seal 60 that can be inserted between each lateral side of the exchanger 18 and an adjacent structural arm (at Figure 2 's configuration).

[0101] Preferably, the transverse seal 60 is made of the same material as the first seal 56. Advantageously, the transverse seal 60 is able to ensure the sealing of the exchanger 18 in the flow channel along the circumferential direction by absorbing the circumferential gap between the exchanger 18 and the adjacent structural arm. Therefore, the transverse seal 60 always remains in contact with the structural arm to ensure the sealing and thermal insulation of the corresponding structural arm.

[0102] Advantageously, each exchanger 18 comprises a first seal 56, a second seal 58 and two transverse seals 60. In this respect, said seals 56, 58, 60 may correspond to one and the same seal.

[0103] In this configuration, the common seal remains integral with the body of the exchanger and can advantageously be disassembled simultaneously with the exchanger 18. Said common seal can then be visually inspected each time the exchanger 18 is disassembled, thus facilitating its replacement.

Claims

1. A turbine (2), comprising: - a first separation lip (10) capable of separating the incoming air flow (F) into a radially inner air flow (F') and a radially outer air flow (F2), the latter being called secondary flow (F2); - a second separation lip (14) capable of separating the radially inner air flow (F') into a main flow (F1) and a tertiary flow (F3), the tertiary flow flowing through a tertiary flow channel (16) being radially outside the main flow channel (16) passed through by the main flow (F1); - a heat exchanger (18) arranged in the tertiary flow channel (16); and - an inner casing (28); The turbine (2) is characterized in that: The heat exchanger (18) comprises a body (32) and a flange (32.1), the flange extending radially inwardly and protruding from the body (32), the flange being fixed to the inner shell (28), the heat exchanger (18) further comprising an upstream portion (50) upstream of the flange (32.1), the upstream portion comprising a collar (52) protruding and extending upstream from the body (32) of the heat exchanger (18), the collar (52) being received in a floating manner in a groove (54), the groove extending circumferentially in the inner shell (28).

2. The turbine (2) according to claim 1, characterized in that The fixing flange (32.1) extends circumferentially over at most 50% of the circumferential extent of the heat exchanger (18).

3. The turbine (2) according to claim 1 or 2, characterized in that The fixing flange (32.1) is arranged at a central position of the heat exchanger (18) along the circumferential direction.

4. The turbine (2) according to any one of claims 1 to 3, characterized in that The flange (32.1) is fixed to the housing (28) by means of fixing elements (33) which enable blind fixing.

5. The turbine (2) according to any one of claims 1 to 4, characterized in that The turbine includes a first thermal insulation seal (56) disposed in the groove (54) and interposed between the housing (28) and the heat exchanger (18).

6. The turbine (2) according to any one of claims 1 to 5, characterized in that The turbine comprises structural arms (34) extending radially through the tertiary flow channel (16) and defining an inter-arm space (36) between the structural arms, the turbine (2) comprising a heat exchanger (18) in each inter-arm space (36), each of the heat exchangers (18) comprising a body (32) and a flange (32.1) extending radially inwardly and protruding from the corresponding body (32), each flange (32.1) being fixed to the inner shell (32), each of the heat exchangers (18) further comprising a transverse insulation seal (60) inserted between the heat exchanger (18) and an adjacent structural arm (34).

7. The turbine (2) according to claim 5 and 6, characterized in that Each of the exchangers (18) comprises the first seal (56) and two transverse insulating seals (60), the transverse seals (60) being integrally formed with the first seal (56).

8. The turbine (2) according to any one of claims 1 to 7, characterized in that The flange (32.1) is arranged in the downstream half of the heat exchanger (18), and downstream of the flange (32.1), the heat exchanger (18) also includes a downstream portion (40) to which a fire wall (46) forming a heat shield is attached.

9. A method for removing a heat exchanger (18) in a turbine (2) according to any one of claims 1 to 8, the method comprising the following steps: - dismantling the fixing element (33) of the flange (32.1) to the inner casing (28); - Removal of the heat exchanger (18) by axial displacement towards the downstream side.

10. A method for installing a heat exchanger (18) in a turbine (2) according to any one of claims 1 to 8, the method comprising the following steps: - installing the heat exchanger (18) by axial displacement towards the upstream side; - Fixing of the flange (32.1) to the fixing element (33) of the inner housing (28).

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