Three-flow axial turbine with heat exchanger

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 flowing through a tertiary flow passage radially outside of the main flow passage through which the main flow passes; -a heat exchanger (18), which is arranged in the third-stage flow channel; and-an inner housing (28); it is notable that the heat exchanger comprises a body (32) and a flange (32.1) extending radially inward and projecting from the body, the flange being fixed to the inner housing, the exchanger comprising a downstream portion (40) downstream of the flange to which a firewall (46) forming a heat shield is attached.

Description

Technical Field

[0001] The present invention relates to the field of turbines, more particularly to three-flow turbines. The present invention relates to an 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 operational limitations due to thermal expansion of the exchanger. The "brick" type exchangers inspired by document FR 3 089248 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] 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 prior art turbines. In particular, the present invention aims to propose a solution that enables efficient cooling in a limited space without increasing the mass and without interfering with the performance of the turbine, while also ensuring the safety of the turbine in the event of a fire and the accessibility of the heat exchanger during maintenance operations.

[0010] To this end, the present invention relates to a turbine comprising:

[0011] 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;

[0012] - 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;

[0013] - a heat exchanger arranged in the tertiary flow channel; and

[0014] - inner housing;

[0015] The heat exchanger comprises a body and a flange extending radially inward and protruding from the body, the flange being fixed to the inner shell, and the heat exchanger further comprises a downstream portion downstream of the flange, a firewall forming a heat shield being attached to the downstream portion.

[0016] Advantageously, the fire wall corresponds to a fire-resistant wall that delays the propagation of a potential fire from the main flow path (e.g. from the combustion chamber) to the rest of the aircraft (towards the aircraft cabin). Attaching the fire wall to the heat exchanger provides an increase in the overall space and also facilitates the maintenance of these elements, since additional fixing of the fire wall is no longer necessary.

[0017] According to an advantageous embodiment of the invention, the downstream portion of the heat exchanger comprises a circumferentially extending groove, and the turbine further comprises an inner shroud of the tertiary flow channel received in the groove.

[0018] Thus, the heat exchanger has a structural function for assembling other components and is no longer just a block arranged in the air flow channel.Thus, the virol does not require specific fastening elements to assemble the virol to the housing or to ensure the continuity of the air flow guiding surface.

[0019] Preferably, the inner shroud 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 shroud are aerodynamically continuous with the tertiary flow channel, and preferably, the casing and the inner shroud constitute the radial inner guide wall of the tertiary flow.

[0020] According to an advantageous embodiment of the invention, the turbine comprises a heat-insulating seal which is arranged in the groove and is inserted between the shroud and the heat exchanger. The seal limits deformations of the shroud which occur due to heat conduction from the shroud to the heat exchanger. Thus, there is no need for fastening elements for the shroud to the housing, the purpose of which is to stiffen the shroud and prevent deformations of the shroud.

[0021] According to an advantageous embodiment of the invention, the downstream portion of the heat exchanger comprises a circumferentially extending groove, and the turbine further comprises an inner shroud of the tertiary flow channel, to which inner shroud the insulation belt is attached and accommodated in the groove.

[0022] Preferably, the insulation strip acts as an additional fire wall, similar to the fire wall in the downstream section of the heat exchanger, to delay the propagation of fire towards the tertiary flow path.

[0023] Advantageously, the heat insulating strip also secures the connection between the shroud and the heat exchanger, so that the heat insulating strip forms together with the fire wall a heat shield extending axially from the flange to the shroud. In this configuration, the inner shroud is protected from the heat that may be emitted from the exchanger, and advantageously, the inner shroud can be made of a composite material.

[0024] According to an advantageous embodiment of the invention, the turbomachine comprises a heat insulating seal which is arranged in the groove and is inserted between the belt and the exchanger.

[0025] According to an advantageous embodiment of the invention, the belt is fixed to the shield and is floatingly mounted in the groove.

[0026] Advantageously, the mounting of the band in the groove is without any fastening and avoids the creation of mechanical stress zones when the exchanger undergoes thermal expansion.To this end, the floating mounting of the shroud in the groove enables expansion deformation in the axial, radial and circumferential directions.

[0027] According to an advantageous embodiment of the invention, the fire wall is fixed to the flange. Thus, fastening elements, in particular screws, can be common to fix the exchanger and the fire wall to the housing.

[0028] According to an advantageous embodiment of the invention, the fire wall at least partially follows the inner contour and the downstream contour of the downstream part of the exchanger.Therefore, the overall size of the "exchanger and fire wall" assembly is minimized.

[0029] Preferably, the inner contour of the downstream portion is substantially parallel to the axis of the turbine, the downstream contour being substantially radial.

[0030] According to an advantageous embodiment of the invention, the axial length of the downstream portion is between 20% and 50% of the axial length of the heat exchanger.

[0031] In this configuration, the flange extends radially inwardly and protrudes from the body, preferably in the downstream half of the heat exchanger. This facilitates assembly / disassembly from the downstream side because the flange is easily accessible without mechanically unbalancing the cantilever mounting of the downstream portion of the heat exchanger.

[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, the turbine comprising a heat exchanger in each inter-arm space, each heat exchanger comprising a body and a flange extending radially inwards and protruding from the respective body, each flange being fixed to the inner casing, a fire wall being fixed to each of the heat exchangers. To this end, the fire wall extends circumferentially 360° around the longitudinal axis of the turbine, thereby ensuring thermal insulation continuity and thermal separation, so as to be able to protect the entire upstream radially outer portion of the turbine from potential fire propagation.

[0033] Advantageously, the fixing of the heat exchanger in the tertiary flow channel limits the aerodynamic disturbances of the flow necessary for the thrust of the aircraft.

[0034] According to an advantageous embodiment of the invention, the turbomachine further comprises a fixing flange of the shroud, said flange having an upstream end fixed to a flange of the heat exchanger, the fire wall being comprised in the flange.

[0035] According to an advantageous embodiment of the invention, the flange comprises a radial portion radially overlapping the downstream portion of the heat exchanger, the radial portion of the flange comprising at least one opening traversed by at least one hydraulic connection connected to the heat exchanger. The hydraulic connection makes it possible to supply oil to the heat exchanger and / or to recover cooled oil from said heat exchanger.

[0036] According to an advantageous embodiment of the invention, the turbomachine comprises a collar which extends protrudingly downstream from the body of the heat exchanger, said collar being flush with the shroud.

[0037] Advantageously, the collar maintains the aerodynamic continuity of the tertiary flow channel to prevent any radially inward air leakage towards the fixing flange.

[0038] Furthermore, the collar enables thermal insulation and also secures the connection between the shroud and the heat exchanger, thereby creating a thermal break extending axially from the body of the heat exchanger to the shroud. In this configuration, the inner shroud is protected from the heat that may be radiated from the heat exchanger, and advantageously the inner shroud can be made of composite material.

[0039] According to an advantageous embodiment of the invention, the fire wall is attached to the underside of the collar.

[0040] Advantageously, the fire wall corresponds to a fire-resistant wall that delays the propagation of a potential fire, for example from a main flow path (e.g. from a combustion chamber) to the aircraft cabin. Attaching the fire wall to the heat exchanger provides an increase in the total space and also facilitates the maintenance of these elements, since additional fixing of the fire wall is no longer necessary.

[0041] Preferably, the fire wall extends from the flange to the collar, thereby forming a heat shield over the entire downstream portion of the heat exchanger.

[0042] According to an advantageous embodiment of the invention, the collar extends axially over at most 10% of the total axial length of the heat exchanger. Advantageously, such an axial length of the collar ensures an axial separation and distance between the downstream portion of the heat exchanger and the upstream portion of the inner shroud, thereby promoting thermal insulation of said inner shroud.

[0043] According to an advantageous embodiment of the invention, the turbine comprises an insulation belt inserted between the heat exchanger and the shroud, said belt having an upper surface resting on the lower surface of the groove of the heat exchanger and a lower surface fixed to the shroud.

[0044] Preferably, the insulation strip acts as an additional fire wall, similar to the fire wall in the downstream section of the heat exchanger, to delay the propagation of fire towards the tertiary flow path.

[0045] Advantageously, the heat insulating strip also secures the connection between the shroud and the heat exchanger, so that the heat insulating strip together with the fire wall forms a heat shield extending axially from the fixing flange to the shroud. In this configuration, the inner shroud is protected from the heat that may be emitted from the heat exchanger, and advantageously, the inner shroud can be made of a composite material.

[0046] According to an advantageous embodiment of the invention, the turbomachine comprises a thermal insulation seal which is interposed between the belt and the heat exchanger.

[0047] The insulating seal is able, on the one hand, to limit the heat transfer from the heat exchanger to the inner shroud and, on the other hand, to allow expansion deformations in the axial, radial and circumferential directions by elastic deformation of said seal. In fact, the band is mounted in the groove without any tightening and avoids the creation of mechanical stress areas when the exchanger undergoes thermal expansion.

[0048] The seal limits the deformation of the shield that occurs due to the heat transfer of the shield to the heat exchanger.The seal thus eliminates the need for reinforcing elements of the shield intended to prevent its deformation (which may be heavy and bulky).

[0049] According to an advantageous embodiment of the invention, the flange is a fire wall.

[0050] According to an advantageous embodiment of the invention, the fire wall is integrated into the exchanger or fixed to a flange of the exchanger.

[0051] Preferably, the fire wall fixed to the flange corresponds to a flange serving as or comprising a fire wall and fixed to said flange.

[0052] 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, the turbine comprising a heat exchanger in each inter-arm space, each heat exchanger comprising a body and a flange extending radially inwards and protruding from the respective body, each flange being fixed to the inner casing, the flange being common to all exchangers, the upstream end of the flange being fixed to each of the flanges of the exchanger. To this end, the flange extends circumferentially 360° around the longitudinal axis of the turbine, thereby ensuring effective support of the inner shroud.

[0053] At the same time, the fire wall extends circumferentially 360° around the longitudinal axis, thereby ensuring thermal insulation continuity, making it possible to protect the entire upstream radially outer portion of the turbine from potential fire propagation.

[0054] The present invention also relates to a turbine, comprising:

[0055] 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 referred to as said secondary flow;

[0056] - 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;

[0057] - a heat exchanger arranged in the tertiary flow channel;

[0058] - an inner casing; and

[0059] An inner shroud of the tertiary flow channel, arranged downstream of the exchanger.

[0060] 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 includes a downstream portion in a cantilever state downstream of the flange. The turbine also includes a fixed flange of the shroud, and the upstream end of the flange is fixed to the flange of the heat exchanger.

[0061] The downstream portion is cantilevered downstream of the fixing flange, since it does not have any other fixing than fixing the heat exchanger to the shroud at said fixing flange.

[0062] The invention comprises at least one of the advantageous embodiments of the invention described above.

[0063] 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 and the formation of the support of the shroud. In this configuration, the number of intermediate components 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.

[0064] Furthermore, the invention is particularly advantageous because the positioning of the heat exchanger at the tertiary flow passage avoids obstructing the passage of air in the secondary flow, thereby avoiding obstructing the efficiency of the engine. This results in optimized energy efficiency and thrust, which advantageously reduces fuel consumption and greenhouse gas emissions, thereby reducing the environmental impact of the aircraft.

[0065] 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

[0066] [ 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;

[0067] [ Figure 2 ] shows Figure 1 A front view of a three-stage flow passage including a plurality of heat exchangers;

[0068] [ Figure 3 ] shows a cross-sectional view of the assembly of the inner shell on the exchanger according to the first embodiment of the present invention;

[0069] [ Figure 4 ]yes Figure 3 An enlarged cross-sectional perspective view of the assembly of the inner shell layer on the exchanger;

[0070] [ Figure 5 ] shows a cross-sectional view of the assembly of an inner shell on an exchanger according to an alternative to the first embodiment of the invention;

[0071] [ Figure 6 ] shows a cross-sectional view of the inner shell being mounted on the exchanger by means of a fixing flange according to a second embodiment of the invention;

[0072] [ Figure 7 ] shows a cross-sectional view of the inner shell being mounted on the exchanger by means of a fixing flange according to a third embodiment of the present invention;

[0073] [ Figure 8 ]yes Figure 6 an enlarged cross-sectional view of an assembly of , wherein the flange includes at least one hydraulic connector;

[0074] [ Fig. 9 ] schematically shows a front view of a flange including at least one hydraulic connection. DETAILED DESCRIPTION

[0075] 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.

[0076] The accompanying drawings schematically illustrate components and are not drawn to scale. In particular, some dimensions are exaggerated to facilitate reading of the drawings.

[0077] Figure 1 A turbomachine 2 is shown, comprising a propeller 4 fixed to a hub 6 , which rotates about a longitudinal axis 8 .

[0078] 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.

[0079] 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 .

[0080] 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 .

[0081] 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′.

[0082] 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.

[0083] The tertiary flow F3 enters the tertiary flow passage 16 which is radially outside the main flow F1 and passes through the heat exchanger 18 , 118 , 218 arranged in the tertiary flow passage 16 .

[0084] The heat exchanger 18 , 118 , 218 extends radially and axially in the tertiary flow channel 16 , preferably in an upstream section 20 of the tertiary flow channel 16 , which has a longitudinal section that branches off in the flow direction of the tertiary flow F3 .

[0085] 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.

[0086] 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 .

[0087] 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.

[0088] The heat exchanger 18, 118, 218 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.

[0089] A single heat exchanger 18, 118, 218 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, 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.

[0090] 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.

[0091] 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, 118, 218 constitute the radially inner guide wall of the tertiary flow F3.

[0092] Figure 2 yes Figure 1 FIG. 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 , 118 , 218 . It can be seen that the exchangers 18 , 118 , 218 are distributed in the tertiary flow channel 16 at an angle.

[0093] 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.

[0094] 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.

[0095] Preferably, the exchanger 18 , 118 , 218 is obtained by additive manufacturing, said exchanger 18 , 118 , 218 extending circumferentially between two structural arms 34 in each inter-arm space 36 .

[0096] The exchanger 18, 118, 218 comprises a heat exchange surface 38 corresponding to the oil channel and / or a heat exchange surface for air extending radially and axially in the inter-arm space 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 surface 38 or of the inner oil channel not being central to the present invention.

[0097] The exchanger 18, 118, 218 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, 118, 218 has a limited extent: the flange 32.1 is centrally located relative to the body 32 in the circumferential direction. This advantageously enables the exchanger 18, 118, 218 to expand freely thermally by enabling it to extend tangentially in the inter-arm space 36.

[0098] Preferably, the assembly direction of the exchanger 18, 118, 218 in the turbine is from downstream to upstream. In this configuration, the fixing of the exchanger 18, 118, 218 to the inner casing 28 can be ensured by a screw connection. Thus, the flange 32.1 can be fixed to the annular flange 28.1 by two to six screws, more preferably by three screws.

[0099] The exchanger 18, 118, 218 also comprises a downstream portion 40, which is arranged downstream of the flange 32.1 and is therefore mounted in a cantilever 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.

[0100] 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.

[0101] The oil inlet 42 and the oil outlet 44 are fluidly connected to an oil collector and an oil distributor, which are arranged in an inner part (not shown) of the body 32 of the exchanger 18, 118, 218. Preferably, the inner part of the body 32 may be hollow and free of material (except for the oil collector and distributor and the fluid connections) to lighten the exchanger 18, 118, 218.

[0102] The downstream portion 40 of the exchanger 18 according to the first embodiment of the invention comprises, on its downstream surface 40.2, a groove 48 intended to receive, directly or indirectly, a shell 30 (see Figures 3 to 5 ).

[0103] At the downstream surface 40.2 and radially outside the oil inlet 42 and the oil outlet 44, the exchanger 118 according to the second embodiment of the invention comprises a collar 54 extending downstream from the body 32 of the exchanger 18. The exchanger 218 according to the third embodiment of the invention comprises a recess 154. The different embodiments will be described in detail later in this description.

[0104] Figure 3 A cross-sectional view is shown of the assembly of an inner shell 30 on an exchanger 18 according to a first embodiment of the invention.

[0105] The downstream portion 40 comprises a fire barrier 46 capable of delaying the propagation of a downstream fire upstream of the turbine 2 .

[0106] The fire wall 46 may correspond to a layer of heat-insulating material such as high-performance plastic. Preferably, the fire wall 46 is polyimide. Available from DuPont TM Advantageously, the polyimide It is a plastic that resists cracking at very high temperatures and has excellent friction and wear characteristics. Unlike most plastics, Even at high temperatures no noticeable gas generation occurs.

[0107] Preferably, the fire wall 46 is fixed to the flange 32.1 and extends from said flange 32.1 to a groove 48 arranged at right angles to the downstream surface 40.2, radially outside the oil inlet 42 and the oil outlet 44. The fixing of the fire wall 46 to the body 32 of the exchanger can be ensured by gluing or screwing.

[0108] Alternatively, preferably, the fire wall 46 is integrally formed with the body 32. In this regard, both the body 32 and the fire wall 46 are formed of aluminum. In this configuration, the fire wall 46 corresponds to an aluminum wall that can be further thickened relative to the rest of the body 32. In fact, the fire wall 46 is thick enough to provide resistance to possible fires.

[0109] The flange 32.1 of each exchanger 18 is fixed to the inner casing 28, and a fire wall 46 is fixed to each flange 32.1. For this purpose, advantageously, the fire walls 46 extending in the flow channel of all exchangers 18 make it possible to cut off a common circumferential thermal bridge with the structural arms 34, thus protecting the entire upstream part of the turbine over 360°.

[0110] Preferably, the groove 48 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 .

[0111] To this end, according to two embodiments (on the one hand Figure 3 and Figure 4 An embodiment, on the other hand, is Figure 5 The installation of the inner shell 30 on the exchanger 18 is performed in accordance with an embodiment of the present invention.

[0112] Still combined Figure 3 It can be seen that the inner shell 30 is accommodated in the groove 48 , wherein the heat insulating seal 50 is arranged in the groove 48 and is inserted between the shell 30 and the exchanger 18 .

[0113] Preferably, the mounting of the ferrule 30 in the groove 48 is a floating mounting and without any fixing.

[0114] In this respect, the insulating seal 50 is an elastomer capable of breaking the thermal bridge between the shell 30 and the exchanger 18. Preferably, the seal 50 is a polyimide. Available from DuPont TM Thus, the seal 50 may be similar to the material of the firewall 46 . However, the seal 50 may be obtained from a different material than the firewall 46 .

[0115] Advantageously, the seal 50 may have elastic mechanical properties enabling it to absorb part of the thermal expansion of the exchanger 18 in the axial and radial directions, avoiding the propagation of mechanical stresses towards the shell 30 and preventing any risk of deformation and / or rupture.

[0116] The axial length of the downstream portion 40 is between 10% and 50%, preferably between 20% and 50%, more preferably between 20% and 40% of the axial length of the exchanger 18. Such an axial length makes it possible to extend the axial coverage of the firewall 46 and thus further extend the protection axially without compromising the mechanical balance of the exchanger: a downstream portion that is too large would require other means to be fixed downstream of the exchanger and this would affect the size and simplicity of the assembly.

[0117] Preferably, the fire wall 46 matches the inner profile 40.1 and the downstream profile 40.2 of the downstream portion 40 of the exchanger 18, the fire wall 46 extending radially on the flange 32.1 and up to the groove 48. Advantageously, in addition to protecting the turbine from the effects of the spread of fire, the fire wall 46 also makes it possible to protect the shell 30 from the high temperatures of the exchanger 18.

[0118] Advantageously, the ferrule 30 can be made of a composite material. For example, the inner ferrule 30 can be made of carbon fiber.

[0119] In fact, during operation of the exchanger 18 , the maximum temperature that the firewall 46 and the seal 50 can reach is lower than the maximum temperature that the composite material forming the inner shell 30 can withstand.

[0120] Advantageously, the direct mounting of the ferrule 30 on the exchanger, through the groove 48 , is carried out from downstream to upstream and by simple insertion, thus facilitating the accessibility of the exchanger 18 and the maintainability of the exchanger 18 .

[0121] The seal 50 matches the hollow shape of the groove 48 on one side and matches the shape of the upstream portion 30 . 1 of the ferrule on the other side.

[0122] Figure 4 is an enlarged perspective cross-sectional view of the assembly of the inner shell 30 on the exchanger 18. This is precisely an enlarged view of the upstream portion 30.1 of the shell 30 inserted into the groove 48.

[0123] refer to Figure 4 Preferably, the upstream portion 30 . 1 comprises an upstream nozzle 30 . 2 , the seal 50 matching the shape of said upstream nozzle 30 . 2 to ensure a fluid tight seal between the shell 30 and the exchanger 18 .

[0124] The upstream portion 30.1 also comprises a platform 30.3 which is arranged radially outside the upstream nozzle 30.2 and flush with the radially inner guide wall 13 so as to follow the Figure 1 Aerodynamic lines 16 . 1 of the air flow in the tertiary flow channel 16 are shown.

[0125] In this configuration, the downstream surface 40.2 may include a housing 49 that can house the platform 30.3 and prevent air from flowing toward Figure 1 The flow channel compartment 27 of the flow channel fairing 26 leaks.

[0126] Figure 5 A cross-sectional view showing the assembly of an inner shell 30 on an exchanger 18 according to an alternative to the first embodiment of the invention is shown.

[0127] exist Figure 5 It can be seen in FIG. 4 that, in this embodiment, the inner shell 30 is supported indirectly by the exchanger 18 . In fact, the upstream portion 30 . 1 comprises insulating tabs 52 housed in the grooves 48 .

[0128] Preferably, the tab 52 comprises a downstream portion 52 . 2 fixed to the upstream portion 30 . 1 of the collar 30 by riveting.

[0129] The heat insulating tab 52 comprises a beak 52.1, which preferably has a shape similar to Figure 4 Due to the shape of the upstream beak 30 . 2 , the mounting of the tab 52 in the groove 48 is floating.

[0130] In this configuration, the seal 50 matches the shape of the tab 52 , the seal 50 making it possible to cut off the thermal bridge between the shell 30 and the exchanger 18 .

[0131] Preferably, the tab 52 is formed of a thermally insulating material that can correspond to the material of the fire wall, i.e., polyimide.

[0132] Advantageously, according to Figure 5 In the embodiment of the invention, the fire wall 46 extends in the downstream portion 40 of the exchanger 18 from the flange 32 . 1 towards the fixed downstream portion 52 . 2 of the tab 52 .

[0133] For this reason, the upstream portion 30.1 is not in direct contact with the seal 50, thereby minimizing the transfer of heat dissipated by the exchanger 18 to the shell 30. Furthermore, this allows greater freedom in the design of the exchanger 18 and the shell 30, the tab 52 being able to act as an adjustable variable filling the gap between these two elements. Figure 5 The switch 18 in the figure illustrates the versatility of the design. Figure 5 The exchanger 18 in the axial direction is Figure 2 The switch in is short.

[0134] Advantageously, the fire wall 46 ensures the interruption of the thermal bridge, thereby making it possible to protect the entire upstream radially outer portion of the turbine from the spread of fire.

[0135] The tabs 52 have a low mass, thus allowing the turbine of the invention to have a significantly reduced mass compared to prior art turbines.

[0136] The tabs 52 also facilitate assembly and disassembly of the exchanger, since they are only fixed to the shell 30 and float in the exchanger 18 , which makes it possible to save time during assembly and improve the maintainability of the turbine.

[0137] Figure 6 A cross-sectional view is shown of the mounting of the inner shell 30 on the exchanger 118 by means of the fixing flange 60 according to a second embodiment of the invention.

[0138] The same elements as those of the first embodiment are denoted by the same reference numerals, while the reference numerals of the elements showing differences are increased by 100.

[0139] Preferably, the collar 54 and / or the recess 154 extend circumferentially over the entire circumferential extent of the downstream portion 40 .

[0140] It can be seen that the fixing flange 60 of the ferrule 30 comprises an upstream end 60.1 fixed directly to the flange 32.1. In this respect, preferably, the flange 32.1 is fixed to the inner housing 28 by a threaded connection, and the upstream end 60.1 is also screwed to the flange 32.1 by the same screws that assemble the flange 60 to the inner housing 28.

[0141] The flange 60 comprises a downstream end 60.2 opposite the upstream end 60.1, said downstream end 60.2 being rigidly connected to the upstream portion 30.1 of the shell 30. Preferably, the rigid connection between the flange 60 and the shell 30 corresponds to a bolt connection and / or a riveting. In this configuration, the shell 30 is attached to the casing via the flange 32.1 of the exchanger 118. This may be the only upstream attachment of the shell 30. Figure 6 A downstream attachment of the shell 30 is shown which will not be discussed in detail herein.

[0142] The downstream portion 40 of the exchanger 118 comprises a collar 54 which extends towards the shell 30 and which is preferably flush with the upstream portion 30 . 1 . To this end, the collar 54 is flush with the radially inner guide wall 13 .

[0143] Thus, the collar 54 enables the tertiary flow to follow Figure 1 The aerodynamic line 16.1 in the tertiary flow channel 16 is shown. The aerodynamic continuity ensured by the collar 54 makes it possible to avoid air Figure 1 The flow channel compartment 27 of the flow channel fairing 26 leaks.

[0144] The collar 54 may be integral with the body 32 , the collar 54 extending axially to the downstream junction 54 . 1 over at most 10% of the total axial length of the exchanger 118 , preferably over 5% of said length.

[0145] Preferably, the fire wall 46 extends to the lower surface 54.1 of the collar 54. This makes it possible to effectively cut off the thermal bridge between the shell 30 and the exchanger 118.

[0146] The flange 60 may also correspond to a second fire wall, in addition to the fire wall 46 of the downstream portion 40 of the exchanger 118. In this configuration, the fire protection and thermal insulation of the component are maximized.

[0147] Alternatively, the flange 60 may comprise a fire wall and the downstream portion 40 of the exchanger 118 may be free of fire walls. This makes it possible to simplify the manufacture of the exchanger 118.

[0148] Figure 7 A cross-sectional view is shown of the mounting of the inner shell 30 on the exchanger 218 by means of the fixing flange 60 according to a third embodiment of the invention.

[0149] The turbine 2 comprises an annular thermal insulation tab 56 inserted between the exchanger 218 and the shell 30 , said tab 56 comprising an upper surface 56 . 1 bearing on the lower surface 154 . 1 of the recess 154 of the exchanger 218 and a lower surface 56 . 2 fixed to the shell 30 .

[0150] Preferably, the downstream portion 56 of the tab 56 is fixed to the upstream portion 30 . 1 of the collar 30 by riveting.

[0151] Preferably, the tab 56 is formed of a thermally insulating material that can correspond to the material of the fire wall, i.e., polyimide.

[0152] Preferably, the lower surface 154.1 of the recess 154 is parallel to the upper surface 56.1 of the tab 56. Preferably, the contact between the tab 56 and the exchanger 218 is indirect contact because the insulating seal 150 is interposed between the upper surface 56.1 and the lower surface 154.1 of the recess 154.

[0153] In this configuration, the gasket 150 makes it possible to cut off the thermal bridge between the shell 30 and the exchanger 18, thereby minimizing the transfer of heat dissipated by the exchanger 218 to the shell 30. In addition, this allows greater freedom in the design of the exchanger 218 and the shell 30, the tab 56 being able to serve as an adjustable variable portion filling the gap between these two elements. Figure 7 The switch 218 in the figure illustrates the versatility of the design. Figure 7 The switch 218 is Figure 6 The switch is smaller.

[0154] In this regard, the seal 150 is an elastomer capable of breaking the thermal bridge between the shell 30 and the exchanger 218. Preferably, the seal 150 is a polyimide. Available from DuPont TM Thus, the gasket 150 may be similar to the material of the firewall 46 . However, the gasket 150 may be obtained from a different material than the firewall 46 .

[0155] The tab 56 has a low mass (similar to Figure 5 The tabs 52 of the exchanger 18 of the embodiment of the present invention are thus provided so that the turbine of the present invention has a significantly reduced mass compared to the turbines of the prior art.

[0156] Advantageously, the fire wall 46 extends from the flange 32 . 1 towards the lower surface 154 . 1 of the recess 154 in the downstream portion 40 of the exchanger 218 .

[0157] The fire wall 46 ensures that the thermal bridge is cut off, so that the entire upstream radially outer part of the turbine can be protected from the spread of fire.

[0158] The tabs 56 also facilitate assembly and disassembly of the exchanger, since they are only fixed to the shell 30 and float in the exchanger 218, which makes it possible to save time during assembly and improve the maintainability of the turbine. In addition, the assembly leaves the tabs 56 free from local deformation (thermal expansion).

[0159] Figure 8 yes Figure 6 , wherein the flange 60 includes at least one hydraulic connection 58 which is directly connected to the downstream surface 40.2 of the exchanger 118. It should be understood that the Figures 3 to 5 as well as Figure 7 The variant shown in is similarly designed.

[0160] The hydraulic connection 58 corresponds to the fluid connection between the exchanger 118 and other components of the turbomachine, ie the lubrication group, the engine, the gearbox, the engine generator or any electrical component requiring cooling.

[0161] The first connection member 58 may be directly connected to the oil inlet 42, and the second connection member 58 may be connected to the oil outlet 44. Figure 2 shown.

[0162] exist Figure 8 As can be seen in FIG. 5 , the flange 60 comprises openings 62 enabling the passage of the connection pieces 58. These openings 62 may be arranged on a radial portion 60.3 of the flange 60 which radially overlaps the downstream portion 40 of the exchanger.

[0163] Fig. 9 A front view of a flange 60 is schematically shown, comprising two openings 62 , each of which is penetrated by a hydraulic connection 58 .

[0164] Preferably, each opening 62 is opposite to the oil inlet 42 or the oil outlet 44 .

[0165] Alternatively, a seal (not shown) may be integrated between the hydraulic connection 58 and the corresponding opening 62. To this end, the flange 60 can provide the turbine with suitable thermal protection to avoid any failure at the opening 62, in the case where the flange 60 corresponds to a firewall.

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 (21) passed through by the main flow (F1); - a heat exchanger (18; 118; 218), said heat exchanger being arranged in said tertiary flow channel (16); as well as - an inner casing (28); - an inner shroud (30) of the tertiary flow channel (16), the inner shroud being arranged downstream of the heat exchanger (18; 118; 218); The turbine (2) is characterized in that: The heat exchanger (18; 118; 218) comprises a body (32) and a flange (32.1), the flange extending radially inwardly and protruding from the body (32), the flange (32.1) being fixed to the inner casing (28), the heat exchanger (18) further comprising a downstream portion (40) downstream of the flange (32.1) and a firewall (46) forming a heat shield, the firewall (46) being attached to the downstream portion (40) and / or being formed integrally with the downstream portion (40), and / or the turbine (2) further comprising a fixing flange (60) of the shroud (30), the fixing flange having an upstream end (60.1), the upstream end being fixed to the flange (32.1) of the heat exchanger (18; 118; 218), and the firewall (46) being included in the flange (60).

2. The turbine (2) according to claim 1, characterized in that The downstream portion (40) of the heat exchanger (18) includes a circumferentially extending groove (48) in which the shroud is received.

3. The turbine (2) according to claim 2, characterized in that The turbine includes a heat insulating seal (50) disposed in the groove (48) and interposed between the shroud (30) and the heat exchanger (2).

4. The turbine (2) according to claim 1, characterized in that The turbine (2) comprises a fixed flange (60) of the shroud (30), the flange (60) comprising a radial portion (60.3) radially overlapping the downstream portion (40) of the heat exchanger (118; 218), the radial portion (60.3) of the flange (60) comprising at least one opening (62) through which at least one hydraulic connection (58) connected to the heat exchanger (118; 218) passes.

5. The turbine (2) according to claim 1 or 2, characterized in that The turbine includes a collar (54) extending protrusively downstream from the body (32) of the heat exchanger (118), the collar (54) being flush with the shroud (30).

6. Turbine (2) according to the preceding claim, characterized in that The fire wall (46) is attached to the underside (54.1) of the collar (54).

7. The turbine (2) according to any one of claims 1 to 6, characterized in that The turbine includes an insulation belt (56) which is inserted between the heat exchanger (218) and the shroud (30), the insulation belt (56) including an upper surface (56.1) resting on a lower surface (154.1) of a recess (154) of the heat exchanger (218) and a lower surface (56.2) fixed to the shroud (30).

8. The turbine (2) according to claim 7, characterized in that The turbine includes a thermal insulation seal (150) interposed between the thermal insulation belt (56) and the heat exchanger (218).

9. The turbine (2) according to claim 1, characterized in that The downstream portion (40) of the heat exchanger (18) includes a circumferentially extending groove (18), and the turbine (2) further includes an insulation belt (52) attached to the inner shroud (30) and received in the groove (48).

10. The turbine (2) according to claim 9, characterized in that The turbine includes a heat insulation seal (50) disposed in the groove (48) and interposed between the heat insulation belt (52) and the heat exchanger (18).

11. The turbine (2) according to claim 9 or 10, characterized in that The insulation belt (52) is fixed to the shield (30) and is floatingly mounted in the groove (48).

12. The turbine (2) according to any one of claims 1 to 11, characterized in that The fire wall (46) is fixed to the flange (32.1).

13. The turbine (2) according to any one of claims 1 to 12, characterized in that The fire wall (46) at least partially follows the inner contour (40.1) and the downstream contour (40.2) of the downstream portion (40) of the heat exchanger (18).

14. The turbine (2) according to any one of claims 1 to 13, characterized in that The axial length of the downstream portion (40) is between 20% and 50% of the axial length of the heat exchanger (18).

15. The turbine (2) according to any one of claims 1 to 14, characterized in that The turbine comprises structural arms (34) extending radially through the tertiary flow channel (16) and defining inter-arm spaces (36), the turbine (2) comprising a heat exchanger (18) in each inter-arm space (36), each heat exchanger (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 casing (28), the firewall (46) being fixed to each of the heat exchangers (18).

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