Recycling aircraft turbine engine

Abstract

The invention relates to an aircraft turbine engine (10) having: a compressor (14); the invention relates to a turbine engine (10) comprising:-a compressor (20),-an annular combustion chamber (24),-a system (32) for diffusing and rectifying an air flow exiting the compressor to supply the combustion chamber, and-a heat exchanger (38) having: + a first circuit (38a) supplied with exhaust gases from the turbine engine, and + a second circuit (38b) comprising an inlet (38ba) and an outlet (38bb), the inlet of the second circuit is connected to the outlet (34b) of the diffuser (34) by means of a first volute (40a) and the outlet of the second circuit is connected to the inlet (36a) of the rectifier (36) by means of a second volute (40b), the volutes (40a, 40b) comprising connecting arms (82, 84) rigidly connecting annular portions (86, 88, 94) of the volutes, the annular portions of the volutes being fixed or connected to the diffuser (34) and the rectifier (36), respectively.

Description

Technical Field

[0001] The invention relates to an aircraft turbine engine equipped with a volute assembly for implementing a recovery cycle. Background Art

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

[0003] A turbine engine may be equipped with one or more bodies, each body including a compressor rotor connected to a turbine rotor by a shaft.

[0004] There are also turbine engines in which a free turbine is mounted downstream of the turbine engine body. A turbine is free as long as its rotor is not connected to the compressor rotor via a shaft.

[0005] Thus, it should be understood that a turbine engine may include multiple compressors in sequence (eg, a low-pressure compressor followed by a high-pressure compressor), and multiple turbines in sequence (eg, a high-pressure turbine followed by a free turbine or a low-pressure turbine).

[0006] In the present application, a normal cycle turbine engine refers to a turbine engine in which compressed air leaving one or more compressors is supplied directly to the combustion chambers.

[0007] On the other hand, a recovery cycle turbine engine is a turbine engine in which the combustion gases flowing out of one or more turbines are used to heat the compressed air leaving one or more compressors and intended to supply the combustion chambers. This technology makes it possible to improve the performance of the turbine engine, since the amount of fuel required to reach the operating temperature of the turbine engine is less than that required within the scope of a conventional cycle turbine engine.

[0008] Figure 1 A very schematic representation of a recovery cycle turbine engine is shown.

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

[0010] Turbine engine 1 comprises a heat exchanger 7 , a first circuit of which is supplied with combustion gases collected from the outlet of free turbine 5 . Exchanger 7 comprises a second circuit supplied with compressed air leaving compressor 2 and which supplies combustion chamber 3 with heated compressed air.

[0011] When the compressor 2 is of the centrifugal type, the integration of this technology may be complex. A centrifugal compressor is a compressor having an inlet oriented parallel to the longitudinal axis of the turbine engine and an outlet oriented radially relative to this axis. This type of compressor is associated with a diffusion and rectification system of the compressed air flow. The system comprises a diffuser-rectifier assembly and therefore an annular diffuser and an annular rectifier, the annular diffuser being oriented substantially radially and aligned with the outlet of the centrifugal compressor, the annular rectifier being oriented substantially axially to direct the compressed air flow towards the combustion chamber.

[0012] Integrated solutions to this technology have been proposed in the past, including assemblies using two volutes.

[0013] The volute is a duct wound helically around an axis, and the fluid passage cross section of the duct changes stepwise. Within the scope of the present application, the volute comprises an annular duct wound around the longitudinal axis of the turbine engine, the annular duct being connected to a first port and a second port, the first port being located at the outer periphery of the duct and oriented in a tangential direction, and the second port being located at the inner periphery of the duct and oriented in a radial direction.

[0014] The first volute has a second port connected to the outlet of the diffuser and a first port supplying the inlet of the second circuit of the exchanger. The outlet of this second circuit is connected to the first port of the second volute, and the second port of the second volute is connected to the inlet of the rectifier.

[0015] The solution proposed in the past is to first interlock the volute from the paired first ports of the volute to the circumferential end of the smallest cross section of the duct. A solution also consists in moving the volute as close as possible to the centrifugal compressor and the combustion chamber.

[0016] In document FR-A1-3 111 666, the applicant has proposed a volute constructed and arranged so as to optimize its dimensions while limiting the heat exchanges between the fluids circulating in the ducts of the volute. The volute is also designed to facilitate its integration into a turbine engine while limiting the impact on the turbine engine, i.e. limiting structural modifications to the turbine engine.

[0017] In the current technology, the volute is attached to the casing of the turbine engine by means of mounting flanges. The volute is connected to a first upstream flange, which is attached to the compressor casing, and a second downstream flange, which is attached to the casing of the combustion chamber.

[0018] The forces transmitted along the turbine engine are therefore transmitted via the volute, which must therefore have a structural function, namely the function of transmitting structural forces. In addition, the pressure inside the volute causes additional stresses.

[0019] The current geometry of the volute does not allow the structural forces to be transferred and there is a risk that the volute will "open", resulting in:

[0020] - Failure to produce a volute construction adapted to the forces present in normal operation, which results in a short service life of the volute and cracks in normal operation, or in the volute being damaged under extreme forces;

[0021] - Deformations of the volute (greater than a few millimeters) are transmitted to the casing and lead to a degradation of the rotor / stator clearances within the turbine engine, which is closely associated with performance degradation.

[0022] Solutions to these problems have been proposed, such as equipping the volute with threaded tie rods. However, these solutions are not ideal, in particular because they affect the airtightness of the assembly and degrade the aerodynamic performance by introducing a shape that is not aerodynamically optimal.

[0023] The present invention provides a simple, effective and economical solution to the above problems. Summary of the invention

[0024] The invention relates to an aircraft turbine engine, comprising:

[0025] - a compressor, the compressor extending around an axis,

[0026] - an annular combustion chamber extending around the axis,

[0027] - a system for diffusing and rectifying the air flow leaving the compressor in order to supply the combustion chamber, the system comprising:

[0028] an annular diffuser comprising a substantially radially oriented outlet and an inlet supplied by the compressor, and

[0029] - an annular rectifier comprising an outlet for supplying the combustion chamber, and

[0030] - a heat exchanger comprising:

[0031] + a first circuit supplied with exhaust gases from the turbine engine, and

[0032] + a second circuit, the second circuit comprising an inlet and an outlet, the inlet of the second circuit being connected to the outlet of the diffuser through a first volute, the outlet of the second circuit being connected to the inlet of the rectifier through a second volute, the first volute and the second volute being placed side by side, and the first volute and the second volute each comprising an annular duct wound around the axis A, the annular duct being connected to a first port and a second port, the first port being located at the outer periphery of the duct and oriented in a tangential direction, the second port being located at the inner periphery of the duct and defining an annular channel of the air passage,

[0033] Characterized in that the second port of each of the first volute and the second volute includes connecting arms distributed around the axis, which extend axially and / or radially through the channel of the second port and rigidly connect the annular parts of the first volute and the second volute, and the annular parts of the first volute and the second volute are attached or connected to the diffuser and the rectifier respectively.

[0034] The invention thus enables the structural forces to be transmitted through the volute via the connecting arms. The connecting arms ensure the transmission of forces between the annular portion of the volute attached or connected to the rectifier or the first housing and the annular portion of the volute attached or connected to the diffuser or the second housing. These connecting arms are advantageously located in the second port and therefore outside the cross section of the air passage in the duct.

[0035] The turbine engine according to the invention may comprise one or more of the following steps or features considered individually or in combination with one another:

[0036] --The compressor is a centrifugal, axial or hybrid compressor,

[0037] the first volute comprises an upstream annular portion for attachment to a diffuser and / or a first housing of a turbine engine, the upstream portion defining a portion of a duct of the volute and a portion of a second port of the volute, a first connecting arm extending axially from the upstream annular portion through the passage of the second port of the volute,

[0038] - the upstream annular portion of the first volute comprises an annular flange, for example located radially on the inside, for attachment to the diffuser and / or the first housing, for example by means of screw-type elements,

[0039] the first volute and the second volute share an intermediate annular portion defining a portion of the duct of each volute and a portion of the second port of each volute, the first connecting arm extending axially through the passage of the second port of the first volute to the intermediate annular portion,

[0040] - the intermediate annular portion comprises air passage ducts distributed around the axis and each of which comprises a first end opening into the first volute and a second end opening downstream of the diffuser, the second end preferably being in the vicinity of the combustion chamber,

[0041] the air passage duct is inclined radially inwardly relative to the axis from upstream to downstream and is at least partially surrounded by the second volute,

[0042] the second volute comprises a downstream annular portion for attachment to a second casing of the rectifier and / or the turbine engine, the downstream portion defining a portion of the duct of the volute and a portion of the second port of the volute,

[0043] the downstream annular portion of the second volute comprises an annular flange for attachment to the diffuser and / or the second housing, for example by means of screw-type elements,

[0044] - a second connecting arm extends axially through the second port of the second volute from the intermediate portion to the downstream portion,

[0045] - the intermediate part and the downstream part are formed in one piece with the rectifier, the vanes of which form a second connecting arm between these parts,

[0046] - the portions of the ducts defined by said annular portion have a greater thickness than the rest of these ducts,

[0047] - the annular portion is formed entirely in one piece,

[0048] - the number of connection arms of each of the second ports is between 6 and 60, preferably between 8 and 20,

[0049] --The connecting arms are evenly distributed around the axis,

[0050] --The connecting arm has an aerodynamic profile,

[0051] -- the connecting arm in the passage of the second port of the first volute is aligned with the vane of the diffuser,

[0052] - the number of connecting arms in the passage of the second port of the first volute is a factor of the number of vanes of the diffuser,

[0053] -- the connecting arm in the passage of the second port of the second volute is aligned with the blades of the rectifier,

[0054] - the number of connecting arms in the passage of the second port of the second volute is a factor of the number of blades of the rectifier,

[0055] --The diffuser is angled,

[0056] the duct of each of the volutes has a gradually varying passage cross section which is at its maximum value at the first port and at its minimum value at the circumferential end of the duct opposite the first port,

[0057] - the volutes have opposite winding directions so that the first port of the volutes is formed by duct portions that are spaced apart from each other and the smallest cross-section of each duct is located at the larger cross-section of the other duct,

[0058] - each of the volutes has a passage cross section of circular or oval shape extending over an angle of at least 220°,

[0059] - The passage cross section of the first volute does not nest in the passage cross section of the other volute. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Other features and advantages of the present invention will become apparent from the following detailed description and for understanding of the detailed description refer to the accompanying drawings, in which:

[0061] [ Figure 1 ] Figure 1 is a very schematic representation of a recovery cycle aircraft turbine engine;

[0062] [ Figure 2 ] Figure 2 is a partial schematic diagram of an axial cross section of a recovery cycle aircraft turbine engine;

[0063] [ Figure 3 ] Figure 3 yes Figure 2 A schematic perspective view of a volute assembly of a turbine engine in FIG.

[0064] [ Figure 4 ] Figure 4 yes Figure 3 A schematic axial cross-sectional view of a volute assembly in FIG.

[0065] [ Figure 5 ] Figure 5 is a partial schematic diagram of an axial cross section of a recovery cycle aircraft turbine engine according to a first embodiment of the present invention;

[0066] [ Figure 6 ] Figure 6 is Figure 5 A schematic perspective view of a turbine engine shown in FIG.

[0067] [ Figure 7 ] Figure 7 is a partial schematic diagram of an axial cross section of a recovery cycle aircraft turbine engine according to a second embodiment of the present invention; and

[0068] [ Figure 8 ] Figure 8 is Figure 7 A schematic axial cross-sectional perspective view of a turbine engine is shown in FIG. DETAILED DESCRIPTION

[0069] As described above Figure 1 .

[0070] Figures 2 to 4 An aircraft turbine engine 10 is shown.

[0071] The turbine engine 10 is Figure 1 As partially shown in FIG. 1 , a turbine engine generally includes at least one compressor, an annular combustion chamber, and at least one turbine.

[0072] In the example shown, the turbine engine 10 comprises one or two consecutive compressors 12 , 14 , which are therefore attached one after the other and which may both be of the centrifugal type.

[0073] The compressors 12 , 14 are annular in shape and are coaxial and centred on an axis A, which is the longitudinal axis of the turbine engine 10 . Each compressor 12 , 14 comprises a stator 16 and a bladed rotor 18 , called an impeller, rotating inside the stator 16 and about the axis A.

[0074] In the example shown, each compressor 12 , 14 comprises an inlet 20 oriented axially upstream and an outlet 22 oriented radially outward relative to the axis A. Herein, the expressions “upstream” and “downstream” refer to the general flow of air and gases in the turbine engine 10 .

[0075] Thus, compressor 14 is located downstream of compressor 12 .

[0076] Alternatively, turbine engine 10 may include a single compressor that is not necessarily centrifugal. For example, a diffuser may be angled to convert axial flow to radial flow at the outlet of an axial compressor as on a centrifugal compressor or on any compressor configuration between centrifugal and axial.

[0077] Figure 2 The turbine engine 10 in FIG. 1 also includes a combustion chamber 24 located downstream of the compressor 14 .

[0078] The combustion chamber 24 includes two annular walls, namely an inner annular wall 24a and an outer annular wall 24b, defining an annular cavity therebetween, into which compressed air from the compressor 14 and fuel from the injector 26 are injected and mixed.

[0079] The walls 24 a , 24 b are connected to one another by a chamber bottom 28 , which is annular in shape and comprises orifices (not visible) for the passage of compressed air coming from the compressor 14 to supply the chamber 24 .

[0080] The combustion chamber 24 is surrounded by an outer annular casing 29 which carries in particular the injectors 26 .

[0081] In the example shown, the chamber 24 is of the inverted type, since its chamber bottom 28 is located on the downstream side of the chamber. The outlet of the chamber 24 is located on the upstream side of the chamber and is connected to one or more turbines 30 located downstream of the chamber.

[0082] The combustion gases injected into the turbine 30 expand and drive the rotor of the turbine, which is connected to the rotor 18 of at least one of the compressors 12 , 14 by a shaft to drive the rotor of at least one of the compressors to rotate about the axis A.

[0083] Then, the combustion gas is discharged into a not-shown combustion gas discharge nozzle.

[0084] In a conventional cycle turbine engine 10 , the connection from the outlet of the compressor 14 to the combustion chamber 24 is achieved through an air diffusion and rectification system 32 (also referred to as a diffuser-rectifier).

[0085] The system 32 comprises:

[0086] an annular diffuser 34 oriented substantially radially and comprising at its inner periphery an inlet 34a and at its outer periphery an outlet 34b opening radially outwards, the inlet being supplied by the compressor 14 and being radially aligned with the outlet 22 of the compressor; and

[0087] An annular rectifier 36 , which in the example shown is oriented substantially axially and comprises, at its upstream end, an inlet 36 a and, at its downstream end, an outlet 36 b for supplying the combustion chamber 24 .

[0088] A diffuser 34 is located upstream of the chamber 24 and the chamber walls 24a, 24b, and a rectifier 36 surrounds the chamber 24 and the chamber walls 24a, 24b and extends within the housing 29. The diffuser 34 may be clamped to the compressor 12 and / or the stator 16 of the compressor 14. The rectifier 36 may be clamped to the housing 29.

[0089] The diffuser 34 and the straightener 36 may be bladed.

[0090] In a conventional cycle turbine engine 10, the outlet 34b of the diffuser 34 is directly connected to the inlet 36a of the rectifier 36, for example, by an L-shaped bent duct. Alternatively, the compressed air leaving the compressor 14 supplies the combustion chamber 24 directly.

[0091] According to the invention, the turbine engine 10 is of the recovery cycle type, which means that the compressed air leaving the compressor 14 is heated before being injected into the combustion chamber 24 .

[0092] The compressed air is heated by passing through the heat exchanger 38 on the one hand and by passing through the assembly 40 of two volutes on the other hand.

[0093] A heat exchanger 38 is schematically shown and generally comprises two circuits 38a, 38b, namely:

[0094] a first circuit 38a, the inlet 38aa of which is connected to means for collecting the exhaust gases coming from the outlet of the turbine 30 or from the aforementioned exhaust nozzles, and the outlet 38ab of which can also be connected to exhaust nozzles for releasing these gases into the atmosphere, and

[0095] A second circuit 38 b comprising an outlet 38 bb connected to the volute assembly 40 and an inlet 38 ba.

[0096] exist Figure 3 The volute assembly 40 is shown in its entirety in FIG. Figure 2 and Figure 4 A cross section of a volute assembly is shown in FIG.

[0097] The assembly 40 comprises two volutes 40a, 40b which are joined together and are coaxial in this case.

[0098] Each volute 40a, 40b comprises a duct wound in a helical form around an axis, here axis A, preferably over at least 360°, so that the duct performs at least one rotation on itself.

[0099] Each volute 40a, 40b includes a first port 42 located at the outer periphery of the pipe and oriented in a tangential direction, and an annularly shaped second port 44 located at the inner periphery of the pipe and oriented in a substantially radial direction.

[0100] The cross-sectional area of ​​the duct may vary, preferably gradually, around the circumference of the duct. The passage cross section is at a maximum S1 at the first port 42 of each volute 40a, 40b and at a minimum S2 at the circumferential end of the duct opposite the first port 42.

[0101] The volute assembly 40 is connected to the diffuser 34, the rectifier 36 and the exchanger 38 as follows. The volute 40a has a second port 44 connected to the outlet 34b of the diffuser 34 and a first port 42, the second port being connected to the outlet 34b of the diffuser 34 and the first port supplying the inlet 38ba of the second circuit 38b of the exchanger 38. The outlet 38bb of this second circuit 38b is connected to the first port 42 of the second volute 40b, the second port 44 of which is connected to the inlet 36a of the rectifier 36.

[0102] In the example shown, the volute 40a is located upstream of the volute 40b. The volutes 40a, 40b preferably each have a circular or oval passage cross section over their entire circumference. Oval refers to any elliptical, oval or oblong shape. However, other shapes are possible.

[0103] The volutes 40a, 40b are joined together and preferably do not nest in each other, in order to restrict the heat exchange between the air flows circulating simultaneously in the two volutes. This means that the passage cross section of one volute does not overlap with the passage cross section of the other volute. In this case, this means that the passage cross section of each volute is almost completed at 360°. For example, in the case of a circular passage cross section, the passage cross section is completely circular or almost completely circular. This angle is at least 220°, preferably as close to 360° as possible.

[0104] Furthermore, the volutes 40a, 40b extend around and away from the housing 29 and are clamped to the housing as will be described in detail below.

[0105] A plane P is defined as the joining plane of the volutes 40 a , 40 b , which plane passes between the volutes and is perpendicular to the axis A. The plane P here extends just upstream of the diffuser 34 .

[0106] The duct of each volute 40a, 40b comprises an annular skin which defines the above-mentioned passage cross section and which has a substantially constant thickness over the circumferential extent of the annular skin extending around the axis A and over the entire extent of the annular skin when considering the axial cross section of the duct, for example Figure 2 can be seen in.

[0107] As can be seen more clearly in the figures, the first annular boss 46 is located at the inner periphery of the volute 40a and includes a blind threaded screw hole 48 for a screw 50. The second annular boss 52 is located at the inner periphery of the volute 40b and includes a blind threaded screw hole 54 for a screw 56.

[0108] The bosses 46, 50 are applied against annular flanges 58 of the casing 29 or another outer casing of the turbine engine, these flanges 58 comprising passage apertures for the screws 50, 56. The screws 50, 56 are axially oriented and evenly spaced around the axis A. The volutes 40a, 40b are thus attached by clamping.

[0109] The volutes 40a, 40b have opposite winding directions so that their ports 42 are formed by spaced-apart duct sections.

[0110] The ports 42 are independent and spaced apart from one another and are generally diametrically opposed to one another relative to the axis A, for example.

[0111] Therefore, the smallest cross section S2 of each pipe is located at the larger cross section of the other pipe. The largest cross section S1 of each pipe is located at the smaller cross section of the other pipe. This can be particularly useful in Figure 3 Seen in.

[0112] As in Figure 3 It can also be seen in FIG. 4 that the ports 42 are each generally tubular in shape and are respectively coupled to the inlet 38ba and outlet 38bb of the exchanger 38 by suitable means.

[0113] The second port 44 of each volute 40a, 40b comprises two annular walls 60, 62 extending around the axis A and defining an air passageway channel therebetween.

[0114] The walls 60, 62 are substantially parallel and project radially inwards from the joining plane P of the volute and the annular skin of the volute. In the example shown, the walls 60, 62 are frustoconical and converge radially inwards from upstream to downstream. The walls 60, 62 are thus inclined relative to the plane P.

[0115] In the example shown, the volute assembly 40 is formed as a single piece. Thus, the volutes 40a, 40b and the ports 42, 44 of the volutes are formed as a single piece.

[0116] In the case shown, this means that the walls 62 of the two ports 44 merge.

[0117] The walls 60, 62 of the volute 40a have free ends opposite the duct defining a substantially radially oriented connector 64 connected to the outlet 34b of the diffuser 34. This connector 64 is annular in shape and can be attached to the casing 29 or another casing of the turbine engine by screws or the like.

[0118] The walls 60, 62 of the volute 40b have free ends opposite the duct defining a generally axially oriented connector 66 for connection with the inlet 36a of the rectifier 36. The connector 66 is annular in shape and can be engaged to the boss 52 and attached to the housing 29 by the boss.

[0119] In the example shown, the walls 60 , 62 have a thickness similar to or the same as the skin of the duct.

[0120] Figure 5 and Figure 6 A first embodiment of the present invention is shown.

[0121] The turbine engine 1 of the first embodiment includes the above-mentioned Figures 1 to 4 All features described are denoted by the same reference numerals, provided that they do not conflict with the following description.

[0122] The diffuser 34 comprises two annular walls 34c, 34d extending around the longitudinal axis A of the turbine engine 1. These walls 34c, 34d are oriented radially with respect to this axis A and are respectively an upstream wall and a downstream wall. These walls 34c, 34d are connected to each other by vanes 34e and define between them air passage channels also oriented radially.

[0123] The upstream wall 34e has, at its outer periphery facing upstream, a cylindrical rim 70. The rim 70 comprises an outer cylindrical surface 70a and an upstream radial surface 70b. A threaded orifice 72 is formed in the rim 70 and opens into the upstream radial surface 70b.

[0124] An annular casing 74, such as a compressor casing, comprises a downstream annular flange 76 which is applied against the upstream radial surface 70b and which is attached to the rim 70 and the diffuser 34 by means of mounting elements 78 which are screws. The screws pass through holes in the flange 76 and are screwed into threaded holes 72 in the rim 70.

[0125] The downstream wall 34d has an outer cylindrical surface 34d1 at its outer periphery. The downstream wall also has an annular lug 80 at its periphery, the upstream end of which is connected to the downstream wall 34d and the downstream end of which is free and has a radial orientation.

[0126] The outer cylindrical surfaces 70b, 34e1 have substantially the same diameter.

[0127] The rectifier 36 comprises two annular walls 36c, 36d extending around the longitudinal axis A of the turbine engine 1. These walls 36c, 36d have a substantially cylindrical or frustoconical shape and are respectively an inner wall 36c and an outer wall 36d when they extend inside each other. These walls 36c, 36d define between them an axially oriented air passage channel in which the vanes 36e are located.

[0128] In the example shown, the outer wall 36 d is integral with the second volute 40 b , or at least the second volute 40 b forms the outer wall of the rectifier 36 .

[0129] The vanes 36e are formed as one piece with the inner wall 36c, so that they are connected to the inner wall 36c at their radially inner ends. The radially outer ends of the vanes 36e are surrounded by the second volute 40b and can be rigidly connected to the second volute. The inner wall 36c has an upstream portion, which is radially applied against the outer surface 34d1 of the downstream wall 34d of the diffuser 34 and is intended to be inserted between this surface 34d1 and the volute assembly 40.

[0130] The volute assembly 40 in this embodiment differs from the volute assemblies in the previous embodiments, particularly by the presence of connecting arms 82, 84 at the second ports 44 of the volutes 40a, 40b.

[0131] In the first embodiment, the first connecting arm 82 extends in the axial direction through the air passageway of the second port 44 of the first volute 40a from the upstream annular portion 86 of the first volute 40a to the intermediate annular portion 88 common to both volutes 40a, 40b.

[0132] Preferably, the connecting arms 82 have an aerodynamic profile. In the example shown, the connecting arms each have a radially inner leading edge and a radially outer trailing edge. In the example shown, the leading edge has an orientation parallel to the longitudinal axis A of the turbine engine, while the trailing edge has an inclined orientation.

[0133] The number of arms 82 is between 6 and 60, for example between 8 and 20. The number of arms 82 may be a factor of the number of vanes 34 e of the diffuser 34 .

[0134] Preferably, the arms 82 are evenly spaced about the axis A. The arms may be radially aligned with the vanes of the diffuser 34 .

[0135] The upstream annular portion 86 of the first volute 40a is a structural part of the first volute 40a and the volute assembly 40 and is therefore configured to transmit and resist structural forces during operation.

[0136] The upstream portion 86 has a minimum thickness E1 and a maximum thickness E2 of the material. These thicknesses are measured, for example, in the radial direction.

[0137] The upstream portion 86 defines a portion of the second port 44 of the upstream volute 40a, in particular defines an upstream wall of the second port 44, and also defines a portion of the duct of the volute 40a. Figure 5 It can be seen that, for a particular cross section of the pipe having a circular shape about an axis Y1 (perpendicular to the section plane), the upstream portion 86 defines an angle (angle α) of the pipe about this axis Y1 comprised between 5° and 20°.

[0138] The upstream portion 86 comprises an inner cylindrical surface 86a which bears radially against the outer cylindrical surface 70b of the diffuser 34. Thus, the structural portion of the volute 40a is pressed directly against the diffuser 34.

[0139] The upstream portion 86 comprises an inner annular flange 90 attached to the diffuser 34. In the example shown, the flange 90 is interposed between the flange 76 and the surface 70a of the diffuser 34. This flange 90 comprises an axial orifice for the passage of the above-mentioned element 78.

[0140] When we observe Figure 5 When looking at the duct of the first volute 40a in FIG. 1 , we see that the thickness E1 is greater than or equal to the thickness E3, E4 of the rest of the duct, and that the thickness E2 is greater than the thickness E3, E4. In the example shown, it can be seen that, for example, the skin of the duct extending from the upstream end of the upstream portion 86 to the diametrically opposite side with respect to the axis Y1 has a smaller thickness E3.

[0141] The thickness E4 of the skin extending over the last part of the duct is slightly greater than E3. Viewed in cross section, it can be seen that in the area where the duct skins meet, these skins form a Y-shape and have a small additional thickness E4.

[0142] The second connecting arm 84 extends axially and radially through the air passageway channel of the second port 44 of the second volute 40b from the intermediate annular portion 88 of the first volute 40a to the downstream annular portion 94 of the second volute 40b.

[0143] Preferably, the connecting arms 84 have an aerodynamic profile. In the example shown, the connecting arms each have a radially outer leading edge and a radially inner trailing edge. In the example shown, the leading edge has an orientation parallel to the longitudinal axis A of the turbine engine 1, while the trailing edge has an inclined orientation.

[0144] The number of arms 84 is, for example, between 8 and 20. The number of arms 84 may be a factor of the number of vanes 36e of the rectifier 36. Preferably, the arms 84 are evenly spaced about the axis A. The arms may be axially aligned with the vanes 36e of the rectifier 36.

[0145] The downstream annular portion 94 is a structural portion of the second volute 40b and is therefore configured to transmit structural forces and withstand these forces during operation.

[0146] The downstream portion 94 has a minimum thickness E5 and a maximum thickness E6 of the material. These thicknesses are measured in the radial direction or in a substantially radial direction.

[0147] The downstream portion 94 defines a portion of the second port 44 of the downstream volute 40b, specifically a downstream wall or outer wall of the second port 44, and also defines a portion of the duct of the volute 40b. Figure 5 It can be seen that, for a particular cross section of the duct having a circular shape about the axis Y2 (perpendicular to the section plane), the downstream portion 84 defines an angle (angle β) of the duct about this axis Y2 comprised between 10° and 30°.

[0148] The downstream portion 94 comprises an inner cylindrical surface 94a for radially bearing on the radially outer ends of the vanes 36e of the rectifier 36 or for being connected to the vanes 36e of the rectifier 36. Thus, the structural part of the volute 40b is pressed directly against the rectifier 36.

[0149] The downstream portion 94 includes a downstream extension that terminates in an annular mounting flange 94b.

[0150] The annular casing 92 , for example a combustion chamber casing, comprises an upstream annular flange which is attached to the flange 94 b by fastening elements, in this case screws.

[0151] When we observe Figure 5 When looking at the conduit of the second volute 40b, we see that the thickness E5 is greater than or equal to the remaining thicknesses E3, E4 of the conduit, and the thickness E6 is greater than the thicknesses E3, E4.

[0152] In the example shown, it can be seen, for example, that the skin of the duct extending between the portion 94 and the aforementioned Y-shaped portion has a small thickness E3.

[0153] Intermediate portion 88 is located between portions 86 and 94 and is connected to arms 82 and 84, respectively.

[0154] The intermediate portion 88 is also a structural portion of the volutes 40a, 40b and is therefore configured to transmit structural forces and withstand these forces during operation.

[0155] In the example shown, the intermediate portion 88 has a minimum thickness E7 and a maximum thickness E8 of the material.

[0156] Preferably, E1, E5 and E7 are the same or close to each other (within + / - 10%).

[0157] Preferably, E2, E6 and E8 are the same or close to each other (within + / - 10%).

[0158] The intermediate portion 88 defines a portion of the second port 44 of each downstream volute 40a, 40b, and in particular defines a downstream wall of the second port 44 of the first volute 40a and an upstream wall of the second port 44 of the second volute 40b.

[0159] The intermediate portion 88 also defines a portion of the duct of the volutes 40a, 40b. Figure 5 It can be seen that, for a particular cross section of each duct having a circular shape about the axis Y1 , Y2 , the intermediate portion 88 defines an angle (angle γ) of the duct about this axis Y1 , Y2 comprised between 5° and 10°.

[0160] The intermediate portion 88 comprises an inner cylindrical surface 88 a bearing radially on the upstream end of the wall 36 c of the rectifier and thus being clamped radially between the portion 88 and the surface 34 d 1 of the diffuser 34 .

[0161] Thus, the common structural portion of the volutes 40 a , 40 b is applied against the diffuser 34 and the flow straightener 36 .

[0162] The intermediate portion 88 may include air passage ducts 96 distributed around the axis A, each air passage duct including a first end and a second end, the first end leading to the duct of the first volute 40, and the second end leading downstream of the diffuser 34 and located radially inside the rectifier 36 (particularly the inner wall 36c of the rectifier).

[0163] As in Figure 5 As can be seen in Figure 36, the duct 96 is aligned with an aperture 98 formed in the wall 36c to allow air exiting the duct 96 to pass therethrough.

[0164] In the example shown, these ducts 96 are inclined radially inwards relative to the axis A from upstream to downstream and are at least partially surrounded by the second volute 40 b.

[0165] Preferably, the aforementioned lug 80 has a frustoconical portion extending parallel to the general orientation of the ducts 96 in order to guide the air leaving these ducts.

[0166] Preferably, this air is used to cool components of the turbine engine turbine, such as the nozzles and the high-pressure turbine ring. Typically, in a configuration without an exchanger, the air entering the combustion chamber is used as a cold source for cooling the turbine components. With an exchanger, the air heated by the exchanger and reaching the chamber may become too hot to adequately cool these components. Therefore, it is useful to have a cold source upstream of the exchanger.

[0167] The arrangement of the air inlet line 96 at the inlet of the volute 40a enables a combination of sufficiently low temperature and sufficiently high static pressure at the inlet to supply a cooling circuit for turbine components.

[0168] In this embodiment, the annular portion 86, 88, 94 is preferably formed as a single piece with the arms 82, 84. For example, the duct and other parts of the volute 40a, 40b can be attached and welded or brazed to this portion. For example, this is the case with the Y-shaped portion of the skin mentioned above.

[0169] In this embodiment, portions 86, 88, and 94 are made independently of rectifier 36, which is formed from separate components.

[0170] exist Figure 7 and Figure 8 In the alternative embodiment shown, portions 86 , 88 and 94 are also made in one piece with rectifier 36 .

[0171] Thus, the inner wall 36 c of the rectifier 36 is integral with the intermediate portion 88 , or more precisely, the intermediate portion 88 comprises an annular upstream extension forming the inner wall 36 c of the rectifier 36 .

[0172] The vanes 36e are also an integral part of the portions 86, 88, 94. The vanes 36e may be located at a distance from the arms 84, as in the previous embodiments. Alternatively, as shown in the drawings, the arms 84 extend between the walls 36c, 36d to form the vanes 36e.

[0173] In yet another embodiment not shown, the connecting arm 84 could be formed by the vanes 36e of the diffuser, which would also be formed in one piece with the walls 36c, 36d and the portions 86, 88, 94. Thus, the leading edge of the vane 36e forming the connecting arm 84 would be located further downstream than in the previous embodiment.

Claims

1. An aircraft turbine engine (10), comprising: - a compressor (14) extending about an axis (A), - an annular combustion chamber (24) extending around the axis (A), - a system (32) for diffusing and rectifying the air flow leaving the compressor in order to supply the combustion chamber, comprising: an annular diffuser (34) comprising a substantially radially oriented outlet (34b) and an inlet (34a) supplied by the compressor, and - an annular rectifier (36) comprising an outlet (36b) for supplying the combustion chamber, and - a heat exchanger (38), comprising: + a first circuit (38a) supplied with exhaust gases from the turbine engine, and + a second circuit (38b), the second circuit comprising an inlet (38ba) and an outlet (38bb), the inlet of the second circuit being connected to the outlet (34b) of the diffuser (34) through a first volute (40a), the outlet of the second circuit being connected to the inlet (36a) of the rectifier (36) through a second volute (40b), the first volute and the second volute being placed side by side, and the first volute and the second volute each comprising an annular duct wound around the axis (A), the annular duct being connected to a first port (42) and a second port (44), the first port being located at the outer periphery of the duct and oriented in a tangential direction, the second port being located at the inner periphery of the duct and defining an annular channel of the air passage, Characterized in that the second port (44) of each of the first and second volutes (40a, 40b) includes connecting arms (82, 84) distributed around the axis (A), which extend axially and / or radially through the channel of the second port and rigidly connect the annular portions (86, 88, 94) of the first and second volutes, which are attached or connected to the diffuser (34) and the rectifier (36) respectively.

2. The turbine engine (10) according to claim 1, wherein: The first volute (40a) includes an upstream annular portion (86) for attachment to the diffuser (34) and / or the first casing (74) of the turbine engine, the upstream portion defining a portion of a duct of the volute and a portion of a second port (44) of the volute, a first connecting arm (82) extending axially from the upstream annular portion (86) through the passage of the second port of the volute.

3. The turbine engine (10) according to claim 2, wherein: The upstream annular portion (86) of the first volute (40a) comprises an annular flange (90), which is located, for example, radially on the inside and is used to be attached to the diffuser (34) and / or the first housing (74), for example by means of screw-type elements (78).

4. The turbine engine (10) according to any one of claims 1 to 3, wherein: The first volute and the second volute (40a, 40b) share a common intermediate annular portion (88), which defines a portion of the duct of each volute (40a, 40b) and a portion of the second port (44) of each volute, and the first connecting arm (82) extends axially through the passage of the second port of the first volute to the intermediate annular portion (88).

5. The turbine engine (10) according to claim 4, wherein: The intermediate annular portion (88) includes air passage ducts (96) distributed around the axis (A), and each air passage duct includes a first end leading to the first volute (40a) and a second end leading downstream of the diffuser (34).

6. The turbine engine (10) according to claim 5, wherein: The air passage duct (96) is inclined radially inwardly relative to the axis from upstream to downstream, and is at least partially surrounded by the second volute (40b).

7. A turbine engine (10) according to any one of the preceding claims, wherein: The second volute (40b) comprises a downstream annular portion (94) for attachment to the rectifier (36) and / or the second casing (92) of the turbine engine, the downstream portion defining a portion of the duct of the volute and a portion of the second port (44) of the volute.

8. The turbine engine (10) according to claim 7, wherein: The downstream annular portion (94) of the second volute (40b) comprises an annular flange (94) for attachment to the diffuser (36) and / or the second housing (92), for example by means of screw-type elements.

9. A turbine engine (10) according to claim 7 as dependent on any one of claims 4 to 6, wherein: The second connecting arm (84) extends axially through the second port (44) of the second volute (40b) from the intermediate portion (88) to the downstream portion (94).

10. A turbine engine (10) according to claim 7 as dependent on any one of claims 4 to 6, wherein: The intermediate and downstream portions (88, 94) are formed as one piece with the rectifier (36), the vanes (36e) of the rectifier forming a second connecting arm (84) between these portions.

11. A turbine engine (10) according to any one of the preceding claims, wherein: The portion of the ducts defined by the annular portions (86, 88, 94) has a greater thickness than the remainder of the ducts.

12. A turbine engine (10) according to any one of the preceding claims, wherein: The annular portions (86, 88, 94) are all formed as a single piece.

13. A turbine engine (10) according to any one of the preceding claims, wherein: The number of connecting arms (82, 84) of each of the second ports (44) is between 6 and 60, preferably between 8 and 20.

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