AXIAL TRIPLE-FLOW TURBOMACHINE WITH HEAT EXCHANGER

Abstract

TRIPLE-FLOW AXIAL TURBOMACHINE WITH HEAT EXCHANGER The invention relates to a turbomachine, comprising: a first separation nozzle adapted to separate an incoming airflow into a radially internal airflow and a secondary airflow; a second separation nozzle adapted to separate the radially internal airflow into a primary flow and a tertiary flow running through a tertiary flow vein radially external to a primary flow vein running through the primary flow; a heat exchanger (18) disposed in the tertiary flow vein; and an internal casing (28); remarkable in that the exchanger comprises a body (32) and a flange (32.1) extending radially inwardly and projecting from the body, the flange being fixed to the internal casing, the exchanger further comprising, downstream of the flange, a downstream part (40) to which is attached a fire wall (46) forming a thermal shield. (Figure to be published with the abbreviation: Figure 3)

Description

Title of the invention: TRIPLE-FLOW AXIAL TURBOMACHINE WITH HEAT EXCHANGER technical field

[0001] The invention relates to the field of turbomachinery and more particularly to three-flow turbomachinery. The invention concerns the arrangement of a heat exchanger for cooling the oil of the turbomachine. Previous technique

[0002] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0003] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0006] In this context, the invention relates more particularly to aspects related to the arrangement of heat exchangers in turbomachinery. Indeed, in a turbomachine, it is generally necessary to cool the oil in the lubrication circuit. Fication. It is known to have one or more heat exchanger(s) in the tertiary flow of a three-flow turbomachine, that is to say in the radially intermediate flow between the primary flow directed towards the combustion chamber and the external secondary flow.

[0007] Integrating a heat exchanger into the third flow, confined between the primary and secondary flows, presents assembly and accessibility challenges for maintenance, as well as operational constraints due to the heat exchanger's thermal expansion. A "brick" type heat exchanger, inspired by document FR 3 089 248 A1, does not meet these constraints and is therefore unsuitable for the third flow.

[0008] The integration of an exchanger into a third flow of a three-flow turbomachine therefore presents challenges related to its size, assembly, accessibility, operation and also the overall mass of the means used to fix it to the casing. Description of the invention

[0009] The present invention aims to overcome at least one of the drawbacks of the aforementioned prior art. More specifically, the invention aims to provide a simple, efficient, and economical solution to address the drawbacks of prior art turbomachinery design / manufacturing. In particular, the invention aims to provide a solution that enables efficient cooling within a compact footprint without adding mass or compromising turbomachine efficiency, while also ensuring the safety of the turbomachine in case of fire and the accessibility of the heat exchanger during maintenance.

[0010] To this end, the present invention relates to a turbomachine, comprising: - a first separation nozzle capable of separating an incoming airflow into a radially internal airflow and a radially external airflow, called secondary flow; - a second separation nozzle capable of separating the radially internal airflow into a primary flow and a tertiary flow, the latter running through a tertiary flow vein radially external to a primary flow vein through which the primary flow runs; - a heat exchanger located in the tertiary flow stream; and - an internal casing; the turbomachine being remarkable in that the exchanger comprises a body and a flange extending radially internally and projecting from the body, the flange being fixed to the internal casing, the exchanger further comprising, downstream of the flange, a downstream part to which is attached a fire wall forming a thermal shield.

[0011] Advantageously, the fire wall corresponds to a fire-resistant wall that delays the propagation of a potential fire from the primary flow path (from the (e.g., combustion chamber), towards the rest of the aircraft (towards the aircraft nacelle). Bringing the fire wall to the heat exchanger reduces overall space and also simplifies maintenance of these components, as an additional fixing for the fire wall is no longer required.

[0012] According to an advantageous embodiment of the invention, the downstream part of the exchanger comprises a circumferentially extending groove, the turbomachine further comprising an internal shell of the tertiary flow vein which is received in the groove.

[0013] The heat exchanger thus has a structural function for the assembly of other parts and is no longer simply a block placed in an air stream. Therefore, the shell does not require specific fasteners to assemble it to the housing or to ensure the continuity of the airflow guidance surface.

[0014] Preferably, the inner shell and the inner casing correspond to an inter-blade cowling of the turbomachine, which is disposed between the primary flow stream and the tertiary flow stream. Advantageously, the casing and the inner shell are in aerodynamic continuity with the tertiary flow stream and preferably constitute a radially internal guiding wall for the tertiary flow.

[0015] According to an advantageous embodiment of the invention, the turbomachine includes a thermal insulating seal disposed in the groove and interposed between the shell and the heat exchanger. This seal limits the deformation of the shell that would occur due to thermal conduction with a hot heat exchanger. Thus, the need for shell fastening elements to the housing, which would otherwise be required to stiffen the shell and prevent its deformation, is eliminated.

[0016] According to an advantageous embodiment of the invention, the downstream part of the exchanger comprises a circumferentially extending groove, the turbomachine further comprising an internal shell of the tertiary flow vein to which is attached an insulating tab which is received in the groove.

[0017] Preferably, the insulating tongue acts as an additional fire barrier, similarly to the fire barrier of the downstream part of the exchanger, so as to delay the spread of fire towards the tertiary flow vein.

[0018] Advantageously, the insulating tab further secures the connection between the shell and the heat exchanger, so as to form, together with the fire-resistant wall, a protective barrier (thermal shield) extending axially from the mounting flange to the shell. In this configuration, the inner shell is protected from heat that may be released from the heat exchanger; said inner shell can advantageously be made from a composite material.

[0019] According to an advantageous embodiment of the invention, the turbomachine includes a thermal insulating seal disposed in the groove and interposed between the tongue and the exchanger.

[0020] According to an advantageous embodiment of the invention, the tongue is fixed to the ferrule and is floating rise in the throat.

[0021] Advantageously, the mounting of the tab in the groove is free of any fasteners and avoids creating areas of mechanical stress when the heat exchanger undergoes thermal expansion. To this end, the floating mounting of the ferrule in the groove allows for expansion deformations along the axial, radial, and circumferential directions.

[0022] According to an advantageous embodiment of the invention, the fire screen is fixed to the flange. Thus, a single fixing element (in particular a screw) can be used to fix both the heat exchanger and the fire screen to the housing.

[0023] According to an advantageous embodiment of the invention, the fire wall at least partially conforms to the internal profile and the downstream profile of the downstream part of the heat exchanger. The overall size of the "heat exchanger + fire wall" assembly is therefore minimized.

[0024] Preferably, the internal profile of the downstream part is substantially parallel to the axis of the turbomachine, and the downstream profile is substantially radial.

[0025] According to an advantageous embodiment of the invention, the downstream part has an axial length between 20% and 50% of the axial length of the exchanger.

[0026] In this configuration, the flange extends radially inwardly from the body, preferably in a downstream half of the heat exchanger. This facilitates assembly / disassembly from the downstream side, as the flange is easily accessible without mechanically unbalancing the cantilevered assembly of the downstream part of the heat exchanger.

[0027] According to an advantageous embodiment of the invention, the turbomachine comprises structural arms extending radially through the tertiary flow path and defining inter-arm spaces between them. The turbomachine includes a heat exchanger in each inter-arm space. Each heat exchanger comprises a body and a flange extending radially inward and projecting from the respective body. Each flange is fixed to the inner casing. The fire barrier is fixed to each heat exchanger. To this end, the fire barrier extends circumferentially over 360° around the longitudinal axis of the turbomachine, ensuring continuous thermal insulation and a thermal bridge break capable of protecting an entire upstream and radially external portion of said turbomachine from potential fire propagation.

[0028] Advantageously, fixing the exchanger in the tertiary flow vein makes it possible to limit the aerodynamic disturbances of the flow required for the thrust of the aircraft.

[0029] The heat exchanger, in addition to being capable of efficiently cooling the oil by exchanging heat with the air, performs additional functions, such as: providing a fire barrier and a support for the shell. In this configuration, the number of intermediate parts that would have been required to separately perform the various functions is significantly reduced, thus reducing the mass and manufacturing cost of the turbomachine of the invention. As a result, the assembly and disassembly of the exchanger are facilitated, thus improving the maintainability of the turbomachine.

[0030] Furthermore, the invention is particularly advantageous because positioning the heat exchanger at the level of the tertiary flow path avoids obstructing the passage of air in the secondary flow and thus the engine's efficiency. This results in optimized energy efficiency and thrust, which advantageously reduce fuel consumption and greenhouse gas emissions, thereby reducing the environmental impact of aircraft.

[0031] It is understood that each detail of an embodiment below can be combined with each other detail of the other embodiments. Brief description of the drawings

[0032] [Fig-1] represents a longitudinal cross-sectional view of a turbomachine according to the invention, said turbomachine comprising a heat exchanger in a tertiary flow channel;

[0033] [Fig.2] represents a front view of the tertiary flow vein of the [Fig.1] comprising several heat exchangers;

[0034] [Fig.3] represents a cross-sectional view of an assembly of an internal ferrule on the exchanger, according to a first embodiment of the invention;

[0035] [Fig.4] is a cross-sectional and enlarged perspective view of the assembly of the inner shell on the exchanger of the [Fig.3];

[0036] [Fig.5] represents a cross-sectional view of the mounting of the inner shell on the exchanger, according to a second embodiment of the invention. Detailed description

[0037] In the following description, the terms "internal" and "external" refer to positioning relative to the longitudinal axis of rotation of a turbomachine. The axial direction corresponds to the direction along the longitudinal axis of rotation of the turbomachine. The radial direction is perpendicular to the longitudinal axis. Upstream and downstream refer to the direction of flow within the turbomachine.

[0038] The figures show the elements schematically and are not drawn to scale. In particular, some dimensions are enlarged to facilitate reading the figures.

[0039] Fig. 1 illustrates a turbomachine 2 comprising a propeller 4 attached to a hub 6 rotating around a longitudinal axis 8.

[0040] The turbomachine 2 evolves in an airflow F whose movement relative to the turbomachine 2 is generated by the rotation of the propeller 4 and the forward movement of the aircraft on which the turbomachine 2 is mounted.

[0041] The airflow F is separated by a first separating nozzle 10 into a ra- airflow internal radial flow F' and an external radial airflow F2, called secondary flow F2. The propeller 4 can be arranged upstream of the first separation nozzle 10 or downstream.

[0042] The radially internal airflow F' passes through a movable wheel 12 which directs it towards a second separation nozzle 14 suitable for separating the radially internal airflow F' into a primary flow Fl and a tertiary flow F3, the latter being distinct from the secondary flow F2.

[0043] The first separation nozzle 10 includes an internal wall forming a first external guide wall 11 of the radially internal airflow F', said first external guide wall 11 forming a convex profile seen from said radially internal airflow F'.

[0044] The second separation nozzle 14 comprises an external wall forming a second external guide wall 13 for the radially internal airflow F' having passed through the moving wheel 12, said second external guide wall 13 forming a convex profile seen from the tertiary flow F3. For this purpose, the second external guide wall 13 corresponds to a radially internal guide wall 13 of the tertiary flow F3.

[0045] The tertiary flow F3 enters a tertiary flow vein 16 radially external to said primary flow FL. The tertiary flow F3 passes through a heat exchanger 18 disposed in the tertiary flow vein 16.

[0046] The heat exchanger 18 extends radially and axially in the tertiary flow vein 16, and preferably in an upstream section 20 of the tertiary flow vein 16, having a longitudinal section diverging in the direction of the flow of the tertiary flow F3.

[0047] The heat exchanger 18 is arranged axially approximately between the high-pressure compressor 15 and the low-pressure compressor 17, called "booster" 17, at the right of an inter-compressor casing.

[0048] The high pressure compressors 15 and low pressure compressors 17 comprise rotating vanes and straightener vanes arranged in a primary flow channel 21 through which the primary flow Fl passes, the latter heading towards a combustion chamber 23.

[0049] A "VBV" channel 19 (Variabe Bleed Valve) opens axially downstream of the heat exchanger 18 into the tertiary vein 16. It provides a discharge function by redirecting part of the primary flow Fl to the tertiary flow F3 to prevent the high-pressure compressor 15 from clogging when the flow rate of the primary flow Fl becomes too low.

[0050] The heat exchanger 18 can extend continuously over 360° in the upstream section 20 of the flow 16 around the longitudinal axis 8 of the turbomachine 2. Preferably, the turbomachine 2 comprises several heat exchangers 18 extending in the tertiary flow vein 16 and subdividing the vein angularly in a discontinuous manner over 360° around the longitudinal axis 8. Each of said exchangers can independently perform a heat exchange function between air and a fluid.

[0051] A single heat exchanger 18 can combine the cooling of several functions or oil circuits of the turbomachine, depending on various parameters related to the oil cooling requirements, i.e., inlet temperatures, flow rates, required outlet temperature, or air conditions. The different circuits can be in thermal contact or isolated. The heat exchanger 18, and in particular its oil passages, can withstand a low oil temperature of -54°C.

[0052] The upstream section 20 of the tertiary flow vein 16 comprises an external fairing 24 and an inter-vein cover 26, at least one of the external fairing 24 and inter-vein cover 26 being rigidly connected to the exchanger 18. Preferably, the inter-vein cover 26 is fixed to the exchanger 18. Such a fixing will be detailed later in this description.

[0053] The inter-vein cover 26 comprises an internal housing 28, arranged axially between the high-pressure compressor 15 and the low-pressure compressor 17, and further includes an internal shell 30 arranged downstream of the exchanger 18. In this configuration, the internal casing 28 and the internal shell 30 together with the exchanger 18 form the internal radially guiding wall of the tertiary flow F3.

[0054] Fig. 2 is a front view, i.e. in the direction opposite to the airflow, of the tertiary flow vein 16 of Fig. 1 comprising several heat exchangers 18. It can be seen that the exchangers 18 are distributed angularly in the tertiary flow vein 16.

[0055] The turbomachine 2 comprises structural arms 34 extending radially through the tertiary flow vein 16 and delimiting between them inter-arm spaces 36. Preferably, the turbomachine 2 comprises between 2 and 20 structural arms 34.

[0056] In parallel, the inner ferrule can be monobloc and circumferentially continuous over 360°, or said ferrule can be subdivided into several inner ferrules up to 5 ferrules.

[0057] The exchanger 18 is preferably obtained by additive manufacturing, said exchanger 18 extending circumferentially between two structural arms 34 in each inter-arm space 36.

[0058] The heat exchanger 18 comprises heat exchange surfaces 38 corresponding to oil passages and / or heat exchange surfaces with air extending radially and axially in the inter-arm space 36. An example of possible designs is detailed in patent applications BE2021 / 5978, BE2021 / 5979, BE2021 / 5980, BE2021 / 5982 and BE2021 / 5983, the design of the heat exchange surfaces 38 or the internal oil passages not being the core of the present invention.

[0059] The heat exchanger 18 comprises a body 32 with a flange 32.1 extending radially inwardly and projecting from said body 32, such that the flange 32.1 is attached to an annular flange 28.1 belonging to the inner casing 28. Said annular flange 28.1 is preferably continuous over 360° around the longitudinal axis of the turbine, whereas the flange 32.1 of the heat exchanger 18 preferably has a limited extent: the flange 32.1 is in a central position relative to the body 32, along the circumferential direction. This advantageously allows for the thermal expansion of the heat exchanger 18 by permitting it to expand tangentially within the inter-arm space 36.

[0060] The heat exchanger 18 is preferably mounted from downstream to upstream in the turbomachine. In this configuration, the heat exchanger 18 can be attached to the inner casing 28 by screwing. Thus, the flange 32.1 can be attached to the annular flange 28.1 by means of two to six screws, and more preferably by means of three screws.

[0061] The heat exchanger 18 also includes a downstream portion 40 located downstream of the flange 32.1 and thus cantilevered. This downstream portion 40 has an internal surface with an internal profile 40.1, for example cylindrical or conical around the longitudinal axis of the turbomachine, and a downstream surface having a downstream profile 40.2 substantially perpendicular to the longitudinal axis. Alternatively, the shape of the downstream portion 40 may be more freely determined, as inspired by document EP3 674531 AL

[0062] 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.

[0063] The oil inlet 42 and the oil outlet 44 are fluidically connected to an oil collector and an oil distributor located in an internal portion of the body 32 of the heat exchanger 18 (not shown). Preferably, the internal portion of the body 32 can be hollow and free of material (apart from the oil collector and distributor and the fluid connections), so as to reduce the weight of the heat exchanger 18.

[0064] The downstream part 40 also includes on its downstream surface 40.2 a groove 48 which is intended to receive, directly or indirectly, the ferrule 30 (see figures 3-5).

[0065] Fig. 3 represents a cross-sectional view of the mounting of the inner ferrule 30 on the exchanger 18, according to a first embodiment of the invention.

[0066] The downstream part 40 includes a fire wall 46 suitable for delaying the propagation of a downstream fire upstream of the turbomachine 2.

[0067] The fire wall 46 may correspond to a layer of insulating material such as a High-performance plastic. Preferably, the 46 fire barrier is a Vespel® polyimide available from DuPont™. Advantageously, Vespel® polyimide is a crack-resistant plastic at very high temperatures with excellent friction and wear characteristics. Unlike most plastics, Vespel® does not produce significant gas release, even at high temperatures.

[0068] Preferably, the fire wall 46 is fixed to the flange 32.1 and extends from said flange 32.1 to a groove 48 located at the downstream surface 40.2, radially external to the oil inlet 42 and the oil outlet 44. The fixing of the fire wall 46 to the body 32 of the heat exchanger can be ensured by gluing or by screwing.

[0069] Alternatively, the fire wall 46 is preferably formed entirely with the body 32. In this respect, both the body 32 and the fire wall 46 are made of aluminum. In this configuration, the fire wall 46 corresponds to an aluminum wall that can be thicker than the rest of the body 32. Indeed, the fire wall 46 is sufficiently thick to ensure resistance to a potential fire.

[0070] The flange 32.1 of each heat exchanger 18 is fixed to the inner casing 28, and the fire wall 46 is fixed to each flange 32.1. For this purpose, the fire walls 46 of all the heat exchangers 18 extending in the channel advantageously allow, with the structural arms 34, a common circumferential thermal bridge, thus protecting the entire upstream part of the turbomachine over 360°.

[0071] Preferably, the groove 48 extends circumferentially over the entire circumferential extent of the downstream part 40. This allows the inner ferrule 30 of the intervein cover 26 of the [Fig.1] to be supported by the exchanger 18.

[0072] For this purpose, the mounting of the inner shell 30 on the exchanger 18 is carried out according to two embodiments (figures 3 and 4 on the one hand, and [Fig.5] on the other hand).

[0073] Still in relation to [Fig.3], we can see that the inner ferrule 30 is received in the groove 48 with a thermal insulating seal 50 disposed in the groove 48 and interposed between the ferrule 30 and the exchanger 18.

[0074] Preferably, the mounting of the ferrule 30 in the groove 48 is a floating mounting and without any fixing.

[0075] In this respect, the thermal insulating gasket 50 is an elastomer suitable for breaking the thermal bridge between the shell 30 and the heat exchanger 18. Preferably, the gasket 50 is a Vespel® polyimide available from DuPont™. This gasket 50 can therefore be similar to the material of the fire wall 46. However, the gasket 50 can be made from a different material than that of the fire wall 46.

[0076] Advantageously, the seal 50 may have elastic mechanical properties enabling it to absorb part of the thermal expansions of the heat exchanger 18 in the axial and radial directions, so as to prevent the propagation of mechanical stresses towards the ferrule 30 and to protect against any risk of deformation and / or crackling.

[0077] The downstream portion 40 has an axial length between 10% and 50% of the axial length of the heat exchanger 18, and preferably between 20% and 50%, and more preferably between 20% and 40%. Such an axial length allows the axial coverage of the fire wall 46 to be extended, and thus the protection to be extended further axially, without compromising the mechanical balance of the heat exchanger: an excessively large downstream portion would require additional fixing methods downstream of the heat exchanger, which would affect the overall size and ease of assembly.

[0078] Preferably, the fire wall 46 follows the internal profile 40.1 and the downstream profile 40.2 of the downstream part 40 of the heat exchanger 18, and extends radially over the flange 32.1 and up to the groove 48. Advantageously, and in addition to protecting the turbomachine from fire propagation, the fire wall 46 protects the shell 30 from the high temperatures of the heat exchanger 18.

[0079] The ferrule 30 can advantageously be made from a composite material. For example, the inner ferrule 30 can be made from carbon fiber.

[0080] Indeed, the maximum temperature that the fire wall 46 and the seal 50 can reach during the operation of the exchanger 18 is lower than the maximum temperature that the composite material forming the inner shell 30 can withstand.

[0081] The direct mounting of the ferrule 30 on the exchanger by means of the groove 48 is advantageously carried out from downstream to upstream, and by simple insertion, thus facilitating the accessibility of the exchanger 18 and its maintainability.

[0082] The seal 50 fits, on one side, the hollow shape of the groove 48, and on the other side the shape of an upstream portion 30.1 of the ferrule.

[0083] Fig. 4 is an enlarged cross-sectional and perspective view of the assembly of the inner ferrule 30 on the exchanger 18. It is specifically an enlarged view of the upstream portion 30.1 of the ferrule 30 inserted into the groove 48.

[0084] With reference to [Fig.4], the upstream portion 30.1 preferably includes an upstream spout 30.2, the seal 50 conforms to the shape of said upstream spout 30.2 so as to ensure fluidic sealing between the ferrule 30 and the exchanger 18.

[0085] The upstream portion 30.1 further comprises a platform 30.3 arranged radially externally to the upstream nozzle 30.2 and flush with the radially internal guide wall 13, so as to follow the aerodynamic line 16.1 of the airflow in the tertiary flow vein 16 illustrated in [Fig.1].

[0086] In this configuration, the downstream surface 40.2 can include a housing 49 suitable for receiving the platform 30.3 and preventing air leaks towards an inter-vein compartment 27 of the inter-vein cover 26 of the [Fig.1].

[0087] Fig. 5 represents a cross-sectional view of the mounting of the inner shell 30 on the exchanger 18 according to a second embodiment of the invention.

[0088] It can be seen in [Fig.5] that in this second embodiment, the inner ferrule 30 is indirectly supported by the exchanger 18. Indeed, the upstream portion 30.1 includes an insulating tab 52 which is received in the groove 48.

[0089] Preferably, the tongue 52 includes a downstream portion 52.2 which is fixed by riveting to the upstream portion 30.1 of the ferrule 30.

[0090] The insulating tab 52 includes a beak 52.1 preferably having a shape similar to the upstream beak 30.2 of [Fig.4], and the mounting of the tab 52 in the groove 48 is floating.

[0091] In this configuration, the seal 50 fits the shape of the tab 52 and allows the thermal bridge between the ferrule 30 and the exchanger 18 to be cut.

[0092] Preferably, the tongue 52 is formed from an insulating material, said material being able to correspond to that of the fire wall, i.e. Vespel® polyimide.

[0093] Advantageously, the fire wall 46, according to the second embodiment, extends in the downstream part 40 of the exchanger 18, from the flange 32.1 and towards the fixed downstream portion 52.2 of the tongue 52.

[0094] To this end, the upstream portion 30.1 is not in direct contact with the seal 50, thus minimizing the transfer of heat dissipated by the heat exchanger 18 to the shell 30. This also allows for greater design flexibility in the heat exchanger 18 and the shell 30, as the tab 52 can serve as an adjustment variable to fill the gap between these two elements. This design versatility is illustrated by the heat exchanger 18 shown in [Fig. 5], which is axially shorter than the one in [Fig. 2].

[0095] Advantageously, the fire wall 46 makes it possible to ensure the interruption of the thermal bridge capable of protecting an entire upstream and radially external part of the turbomachine from a propagation of fire.

[0096] The tab 52 comprises a small mass, thus enabling the turbomachine of the invention to have a considerably reduced mass compared to state-of-the-art turbomachines.

[0097] Being fixed only to the ferrule 30 and being floating in the exchanger 18, the tab 52 also facilitates the assembly and disassembly of the exchanger, which makes it possible to save time during assembly and to improve the maintainability of the turbomachine.

Claims

Demands

1. Turbomachine (2), comprising: - a first separation nozzle (10) adapted to separate an incoming airflow (F) into a radially internal airflow (F') and a radially external airflow (F2), called secondary flow (F2); - a second separation nozzle (14) adapted to separate the radially internal airflow (F') into a primary flow (F1) and a tertiary flow (F3), the latter flowing through a tertiary flow channel (16) radially external to a primary flow channel (21) through which the primary flow (F1) flows; - a heat exchanger (18) disposed in the tertiary flow channel (16); and - an internal casing (28); the turbomachine (2) being characterized in that the exchanger (18) comprises a body (32) and a flange (32.1) extending radially internally and projecting from the body (32), the flange (32.1) being fixed to the internal casing (28), the exchanger (18) further comprising, downstream of the flange (32.1), a downstream part (40) to which is attached a fire wall (46) forming a thermal shield.

2. Turbomachine (2) according to claim 1, characterized in that the downstream part (40) of the exchanger (18) comprises a groove (48) extending circumferentially, the turbomachine (2) further comprising an internal shell (30) of the tertiary flow vein (16) which is received in the groove (48).

3. Turbomachine (2) according to claim 2, characterized in that it comprises a thermal insulating seal (50) disposed in the groove (48) and interposed between the shell (30) and the exchanger (2).

4. Turbomachine (2) according to claim 1, characterized in that the downstream part (40) of the exchanger (18) comprises a groove (18) extending circumferentially, the turbomachine (2) further comprising an internal shell (30) of the tertiary flow vein (16) to which is attached an insulating tab (52) which is received in the groove (48).

5. Turbomachine (2) according to claim 4, characterized in that it comprises a thermal insulating seal (50) disposed in the groove (48) and interposed between the tongue (52) and the exchanger (18).

6. Turbomachine (2) according to claim 4 or 5, characterized in that the tongue (52) is fixed to the ferrule (30) and is mounted floating in the groove (48).

7. Turbomachine (2) according to any one of claims 1 to 6, characterized in that the fire wall (46) is fixed to the flange (32.1).

8. Turbomachine (2) according to any one of claims 1 to 7, characterized in that the fire wall (46) at least partially follows the internal profile (40.1) and the downstream profile (40.2) of the downstream part (40) of the exchanger (18).

9. Turbomachine (2) according to any one of claims 1 to 8, characterized in that the downstream part (40) has an axial length between 20% and 50% of the axial length of the exchanger (18).

10. Turbomachine (2) according to any one of claims 1 to 9, characterized in that it comprises structural arms (34) extending radially through the tertiary flow vein (16) and delimiting between them inter-arm spaces (36), the turbomachine (2) comprising a heat exchanger (18) in each inter-arm space (36), each of the exchangers (18) comprising a body (32) and a flange (32.1) extending radially inwardly and projecting from the respective body (32), each flange (32.1) being fixed to the inner casing (28), the fire wall (46) being fixed to each of the exchangers (18).

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