Partitioned exhaust casing for a turbine engine

Abstract

The present invention relates to an exhaust casing (0) for a turbine engine, comprising: - a blade assembly (1); - a nozzle cone (2) mounted downstream of the blade assembly (1); - a bearing support (3) arranged radially internally relative to the blade assembly (1); - an electric machine (4) attached to the bearing support (3); - a partition (5) extending so as to define, between the bearing support (3) and the blade assembly (1), a cavity radially beneath the blade assembly (10); - an insulation cowl (6) arranged between the nozzle cone (2) and the electric machine (4); - a service tube (7) connected to the electric machine (4) by passing through the partition (5); such that the partition (5) and the insulation cowl (6) define an electric machine compartment (40) and a nozzle cone cavity (20).

Description

[0001] DESCRIPTION

[0002] TITLE: Partitioned exhaust casing for turbomachine

[0003] TECHNICAL FIELD

[0004] The present invention relates generally to the field of turbomachines, in particular aeronautical turboshaft engines, and more particularly to an aircraft turbomachine exhaust casing.

[0005] The invention relates more specifically, but not exclusively, to an exhaust casing intended to be used in a USF (Unducted Single Fan) type engine, comprising a moving blade and a fixed blade of an unducted aircraft engine fan.

[0006] STATE OF THE ART

[0007] A turbomachine has a longitudinal axis around which it extends and typically comprises, from upstream to downstream in the direction of gas flow, a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, and a low-pressure turbine including in particular an exhaust casing. The exhaust casing helps to delimit the primary flow of the fluid (or primary flow of gases) passing through the turbomachine and ensures, via the bearing support, the concentricity between the rotor and the stator of the turbomachine, as well as optionally the attachment of the downstream part of the engine to the nacelle.

[0008] This exhaust casing conventionally comprises a bearing support, centered on the axis of the turbomachine, a blading which extends between an inner shell and an outer shell, downstream and coaxial with the bearing support, and a set of arms connecting the bearing support and the blading. The exhaust casing is subjected to significant thermal gradients which generate mechanical stresses in the elements, which has an impact on the service life of the exhaust casing as a whole.

[0009] A turbomachine may include other similar casings such as an intermediate casing (interposed between a low-pressure compressor and a high-pressure compressor of the turbomachine, and is therefore crossed by a flow of gas leaving the low-pressure compressor and intended to supply the high-pressure compressor) or an inter-turbine casing (interposed between the high-pressure turbine and the low-pressure turbine).

[0010] The operation of a conventional turbomachine involves, among other things, the passage of electrical cables and the circulation of various fluids through the turbomachine, such as air, oil, or oiled air. In order to convey these fluids, it is known to have pipes in the structure of the turbomachine itself. Some of these pipes, called service tubes, must connect radially external parts of the turbomachine to radially internal parts, and thus cross the primary and secondary air flows.

[0011] It is known to pass servitude elements such as servitude tubes within hollow arms of casings, such as the hollow arms of the exhaust casing, without disturbing the flow of the flow inside the vein thanks to their internal cavity. Generally, each of the servitude elements makes it possible to connect at least a first hydraulic or electrical equipment located radially outside the vein to at least a second hydraulic or electrical equipment located radially inside the vein of the casing. For example, the first hydraulic equipment is a pump and the second hydraulic equipment is a bearing enclosure. Such a second electrical equipment is for example an electric alternator, which can be placed inside the nozzle cone, an aerodynamic element also called a plug or central body and which makes it possible to guide the exhaust gases at the outlet of the turbomachine.

[0012] In this configuration, a major problem is the protection of the second electrical equipment, in particular from oil emissions from the bearing support, but also from radiative heat exchanges with the primary vein and the blading wall, the second electrical equipment having a substantially lower operating temperature than the primary vein and the elements located outside the nozzle cone.

[0013] This protection requirement is opposed by the need to run numerous electrical power and control harnesses, as well as the pipes necessary for the oil circuit in the service tubes between the blades and the second electrical equipment, in an environment where temperature variations cause strong expansions which induce significant relative movements of the elements between them.

[0014] STATEMENT OF THE INVENTION

[0015] One aim of the present application is to remedy the aforementioned drawbacks by proposing a partitioning of the turbomachine casing.

[0016] For this purpose, according to a first aspect of the invention, there is proposed a turbomachine exhaust casing comprising:

[0017] - a blading forming a crown comprising arms which extend between an inner shroud and an outer shroud, the blading extending around an axis extending from upstream to downstream in a direction of circulation of an exhaust flow;

[0018] - an annular nozzle cone, coaxial and mounted downstream of the blading by a nozzle cone flange, the nozzle cone flange being arranged axially between the blading and the nozzle cone; - a bearing support coaxial with the blading and arranged radially inside with respect to the blading;

[0019] - an electrical machine arranged radially inside the nozzle cone, downstream of the bearing support, the electrical machine being fixed to the bearing support by a bearing support flange, the bearing support flange being arranged axially between the electrical machine and the bearing support;

[0020] - a partition extending radially between the nozzle cone flange and the bearing support flange, or between a partition support flange and the bearing support flange, the partition support flange being fixed to the blading or to the nozzle cone, so as to define between the bearing support and the blading a cavity radially under the blading;

[0021] - an insulating cover arranged between the nozzle cone and the electrical machine, coaxial with the electrical machine and the nozzle cone, the insulating cover being connected to the partition by an insulating cover flange;

[0022] - a service tube extending into a housing of an arm of the blade and being connected to the electric machine by passing through the partition by a bulkhead passage; such that the partition and the insulating cover define an insulated electric machine compartment between the partition, the electric machine and the insulating cover and a nozzle cone cavity being delimited by the partition, the nozzle cone and the insulating cover.

[0023] The exhaust casing according to the invention is advantageously supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0024] - the partition comprises on its surface located between the nozzle cone flange and the insulation cover flange a flexibility zone, configured to allow the partition to maintain the seal between the cavity located radially under the blading, the nozzle cone cavity and the electrical machine compartment during a relative movement between the nozzle cone flange and the bearing support flange.

[0025] - the service tube has a ball joint plate or a sliding plate and the bulkhead fitting has a cylindrical boss, so that the service tube slides axially in the bulkhead fitting while maintaining the seal of the partition.

[0026] - the bulkhead fitting comprises a radial fixing plate fixed to the bulkhead by a retaining plate allowing radial play, so that the service tube passing through the fixing plate can move radially while maintaining the seal of the bulkhead, the retaining plate being integral with the bulkhead.

[0027] - the bulkhead fitting comprises a radial support plate fixed to the bulkhead, the support plate comprising a nipple or nozzle type fitting, the fitting being fixed to the support plate and configured to receive the end of a service tube. - the flexible zone of the bulkhead comprises corrugations in the radial direction and / or in the axial direction.

[0028] - the partition and / or the insulation cover includes thermal insulation.

[0029] - the partition includes anti-thermal radiation sheets or is covered with anti-radiation paint.

[0030] - the service tube houses electrical control or power cables, ventilated by air for cooling, these cables being arranged in a sheath, the service tube preferably being configured to also accommodate oil, air or oiled air pipes.

[0031] The invention also relates to a turbomachine comprising a turbomachine exhaust casing according to one of the above embodiments.

[0032] DESCRIPTION OF FIGURES

[0033] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0034] Figure 1 is a partial and simplified sectional view of an exhaust casing according to one embodiment of the invention;

[0035] Figure 2 is a schematic view of an embodiment of a bulkhead fitting according to the invention;

[0036] Figure 3 is a schematic view of a second embodiment of a partition wall pass-through according to the invention;

[0037] Figure 4 is a schematic view of a third embodiment of a bulkhead fitting according to the invention;

[0038] Throughout the figures, similar elements have identical references.

[0039] DETAILED DESCRIPTION OF THE INVENTION

[0040] In the present application, upstream and downstream are defined relative to the normal flow direction of the gas in the casing 0 and through the turbomachine. Furthermore, the longitudinal axis A is the axis of symmetry of the casing 0, which corresponds to the axis of rotation of the fan when the casing 0 is mounted in a turbomachine 8. The axial direction corresponds to the direction of the axis A and a radial direction is a direction perpendicular to this axis and passing through it. Furthermore, the circumferential (or lateral) direction corresponds to a direction perpendicular to the axis A and not passing through it. Unless otherwise specified, internal (respectively, interior) and external (respectively, exterior), respectively, are used with reference to a radial direction such that the internal part or face of an element is closer to the axis A than the external part or face of the same element.In one embodiment, illustrated in FIG. 1, the exhaust casing 0 comprises a blading 1 at the outlet of a primary flow path 11. The blading 1 forms a crown comprising arms which extend between an inner shroud and an outer shroud. Coaxially and downstream of the blading 1 is fixed, by means of a nozzle cone flange 12, a nozzle cone 2 which makes it possible to guide the exhaust gases at the outlet of the primary flow path 11 of the turbomachine. In this embodiment, the turbomachine is a hybrid turbomachine, that is to say that it comprises more particularly an electric machine 4 (which may comprise an electric generator or an electric motor) which is arranged downstream of the exhaust casing 0, coaxially therewith along the main axis A, and which is housed in the nozzle cone 2 inside a nozzle of the turbomachine. The electric machine 4 is fixed to a support, typically a bearing support 3 by a bearing support flange 34a.For its electrical power supply, it is necessary that at least one conductive element for transmitting control signals, called an electrical harness, connects the electrical machine 4 to another member of the turbomachine, another member which is typically external to the primary vein 11. This makes it possible to ensure the electrical connection of the electrical machine 4 for the transmission of energy by power harnesses and information by control harnesses. For thermal regulation and lubrication, services conveying for example air, oil or oiled air must also connect at least one member external to the nozzle cone 2 to the electrical machine 4. To ensure these functions, the casing 0 comprises one or more service tubes 7 in which the necessary sheaths and / or tubes are housed.A tube is understood to mean an oil or air or oiled air conduit and a sheath is understood to mean a conduit containing harnesses of electrical control or power cables, ventilated by air for cooling.

[0041] Alternatively, for certain turbomachines not including a low pressure bearing and therefore not including a bearing support 3, it is possible to use an electric machine support flange 34b, not shown in the figures, the role of which is to fix the electric machine 4.

[0042] Each service tube 7 may comprise one or more electrical control and / or power sheaths, and may also comprise air, oil or oiled air conduits. A service tube 7 thus extends from the blading 1 to the electrical machine 4, being mounted in the blading 1 in a sliding manner, in order to be able to accommodate relative movements, in particular relative movements caused by thermal expansion differences between the blading 1, the temperature of which is much higher than that of a ventilated service tube 7. The invention makes it possible to ensure these connections while isolating the electrical machine 4 from the oil coming from the bearing support 3 and from heat exchanges with the primary vein 11 and the wall of the nozzle cone 2.Thus, the exhaust casing 0 comprises, fixed between the nozzle cone flange 12a and the bearing support flange 34, a partition 5 or radial sheet metal, placed radially so as to define a cavity radially under the blading 10, thus isolating the electrical machine 4 from the bearing support 3. Alternatively, the partition 5 is fixed using a partition support flange 12b, fixed on one or other of the blading 1 or the nozzle cone 2. The partition support flange 12b is a flange dedicated solely to holding the partition 5 in position, which makes it possible to improve the positioning of the partition 5.

[0043] The partition 5 also supports an insulation cover 6 of the nozzle cone 2, via an insulation cover flange 56 which keeps the insulation cover 6 fixed to the partition 5 coaxially with the electrical machine 4. Alternatively, the insulation cover 5 can be fixed at the nozzle cone flange 12. The partition 5 and the insulation cover 6 thus define an electrical machine compartment 40 between the partition 5, the insulation cover 6 and the electrical machine 4 and a nozzle cone cavity 20, between the partition 5, the insulation cover 6 and the nozzle cone 2, in order to thermally insulate the electrical machine 4.

[0044] Compared to the prior art, such compartmentalization of the casing 0 provides several advantages, in particular better thermal insulation of the electrical machine 4 and its protection against oil coming from the bearing support 3, which can pollute the cavity under the blades 10. This also provides an obstacle to the spread of flammable fluids and facilitates their drainage, which limits the risks in the event of a breakdown and helps to prevent fires.

[0045] Optionally, it is possible to further improve the thermal regulation of the electric machine 4 by ventilating the electric machine compartment 40 by forced convection, by taking air from a colder zone of the turbomachine and conveying it into the service tubes 7. The reduced volume of the electric machine compartment 40 compared to the prior art then makes it possible to reduce the quantity of air necessary for its ventilation, which reduces the impact on the general performance of the turbomachine. It is also possible to cool the electric machine 4 using a liquid circuit in the service tubes 7, in combination with ventilation by forced convection or not. Furthermore, the partition 5 and / or the insulation cover 6 may comprise thermal insulating materials in order to limit conductive heat exchanges, for example silica wool.To limit radiative heat exchanges, the partition 5 and / or the insulation cover 6 may also include anti-thermal radiation sheets or an anti-radiation paint coating.

[0046] The partition 5 may comprise, on all or part of its surface located radially between the insulation cover flange 56 and the nozzle cone flange 12, a deformable zone 51, configured to undergo radial and axial elongations elastically while maintaining the sealing of the electrical machine compartment 40. The deformable zone 51 may thus comprise radial and / or axial undulations or be made of materials different from the rest of the partition 5, in order to allow the partition 5 to perform its function during relative movements between the nozzle cone flange 12 and the bearing support flange 34, under the effect of significant temperature gradients during the operating cycle of the turbomachine.

[0047] In order to allow the transmission of power and information between the electric machine and the rest of the turbomachine, the partition 5 comprises one or more bulkhead devices 52 configured to allow one or more service tubes 7 to pass through. Each service tube 7 typically extends from the electric machine 4 to the blading 1 by passing through a bulkhead 52. Each service tube 7 is guided inside the blading 1 so as to be able to slide, so that the partition 5 must be configured to position and hold each service tube 7 in the cavity located radially under the blading 10 and in the electric machine compartment 40.Such an arrangement makes it possible to segregate the connections to the electrical machine 4 from the other circuits of the turbomachine, in particular the secondary air circuit, which reduces interference and therefore the sizing constraints of the pressurization circuits of the enclosures, the drainage circuits and the fire prevention circuits, for example the evacuation circuit called in English "sump flooding".

[0048] Figure 2 illustrates an alternative embodiment in which the service tube(s) 7 each comprise a ball-joint plate 71 or alternatively a sliding plate 71 and the bulkhead 52 comprises a cylindrical boss. The cylindrical boss of the bulkhead 52 and the plate 71 are dimensioned so that the plate 71 slides in the cylindrical boss each service tube 7 can perform axial movements in the bulkhead 52 while maintaining the sealing of the partition 5. In this way, the movements of a service tube 7 relative to the partition 5, induced by thermal expansion, are permitted without being able to compromise the integrity of the insulation.

[0049] Alternatively, as illustrated in Figure 3, the bulkhead 52 may be provided with a radial fixing plate 53 screwed onto the partition 5 or clamped by a holding plate 54 on the partition 5. Advantageously, the holding plate 54 is made integral with the partition 5, in order to increase the rigidity of the fixing of the service tubes 7. The fixing plate 53 is screwed or fixed onto the partition 5 allowing radial play, so that the service tube 7 passing through the fixing plate 53 can move radially while maintaining the sealing of the partition 5. In another embodiment, which is that illustrated in Figure 4, the bulkhead 52 comprises a radial support plate 55 screwed onto the partition 5. Alternatively, the support plate 55 is clamped by a holding plate 54 on the partition 5, in a manner similar to the embodiment of Figure 3 in order to obtain the same advantages.In particular, the holding plate 54 can be made integral with the partition 5, in order to increase the rigidity of the fixing of the service tubes 7. The support plate 55 comprises on each of its faces one or more nipple or nozzle type connections 72, the connections 72 being welded or screwed onto the support plate 55 and configured to receive the end 73 of a service tube 7. This arrangement makes it possible to size the service tubes 7 more efficiently, because those located between the partition 5 and the electrical machine 4, inside the electrical machine compartment 40, are subjected to fewer stresses, in particular thermal stresses, than those located between the blading 1 and the partition 5, in the cavity under the blading 10. This also simplifies maintenance, because it is possible to dismantle only part of the service tubes 7.

[0050] In addition to the advantages already mentioned, the integration of a partition 5 in a turbomachine casing 0 according to the invention provides an improvement in the mechanical strength of the nozzle cone 2, which is fixed in a more constrained area thanks to the partition 5. General maintenance operations of the turbomachine are also facilitated since it is now possible to dismantle the electric machine 4 without opening the engine oil enclosure. The partition 5 also holds the service tubes 7 in positions facilitating these operations.

Claims

CLAIMS 1. Turbomachine exhaust casing (0) comprising: - a blading (1) forming a crown comprising arms which extend between an inner ferrule and an outer ferrule, the blading (1) extending around an axis (A) extending from upstream to downstream in a direction of circulation of an exhaust flow; - an annular, coaxial nozzle cone (2) mounted downstream of the blading (1) by a nozzle cone flange (12), the nozzle cone flange (12) being arranged axially between the blading (1) and the nozzle cone (2); - a bearing support (3) coaxial with the blading (1) and arranged radially inside with respect to the blading (1); - an electrical machine (4) arranged radially inside the nozzle cone (2), downstream of the bearing support (3), the electrical machine being fixed to the bearing support (3) by a bearing support flange (34), the bearing support flange (34) being arranged axially between the electrical machine (4) and the bearing support (3); - a partition (5) extending radially between the nozzle cone flange (12a) and the bearing support flange (34), or between a partition support flange (12b) and the bearing support flange (34), the partition support flange (12b) being fixed to the blading (1) or to the nozzle cone (2), so as to define between the bearing support (3) and the blading (1) a cavity radially under the blading (10); - an insulating cover (6) arranged between the nozzle cone (2) and the electrical machine (4), coaxial with the electrical machine (4) and the nozzle cone (2), the insulating cover (6) being connected to the partition (5) by an insulating cover flange (56); - a service tube (7) extending into a housing of an arm of the blade (1) and being connected to the electric machine (4) by passing through the partition (5) by a bulkhead (52); so that the partition (5) and the insulating cover (6) define an electric machine compartment (40) insulated between the partition (5), the electric machine (4) and the insulating cover (6) and a nozzle cone cavity (20) being delimited by the partition (5), the nozzle cone (2) and the insulating cover (6).

2. Exhaust casing (0) according to claim 1, wherein the partition (5) comprises on its surface located between the nozzle cone flange (12) and the insulation cover flange (56) a flexibility zone (51) comprising undulations in the radial direction and / or in the axial direction and configured to allow the partition (5) to maintain the seal between the cavity located radially under the blading (10), the nozzle cone cavity (20) and the electrical machine compartment (40) during a relative movement between the nozzle cone flange (12) and the bearing support flange (34).

3. Exhaust casing (0) according to one of claims 1 or 2, in which the service tube (7) comprises a ball joint plate (71) or a sliding plate (71) and the bulkhead (52) comprises a cylindrical boss, so that the service tube (7) slides axially in the bulkhead (52) while maintaining the sealing of the partition (5).

4. Exhaust casing (0) according to one of claims 1 or 2, in which the bulkhead (52) comprises a radial fixing plate (53) fixed to the bulkhead (5) by a retaining plate (54) allowing radial play, so that the service tube (7) passing through the fixing plate (53) can move radially while maintaining the sealing of the bulkhead (5), the retaining plate (54) being integral with the bulkhead (5).

5. Exhaust casing (0) according to one of claims 1 or 2, in which the bulkhead (52) comprises a radial support plate (55) fixed to the bulkhead (5), the support plate (55) comprising a nipple or nozzle type connector (72), the connector (72) being fixed to the support plate (55) and configured to receive the end (73) of a service tube (7).

6. Exhaust casing (0) according to one of claims 1 to 5, in which the partition (5) and / or the insulating cover (6) comprises a thermal insulator.

7. Exhaust casing (0) according to one of claims 1 to 6, in which the partition (5) comprises anti-thermal radiation sheets or is covered with anti-radiation paint.

8. Exhaust casing (0) according to one of claims 1 to 7, in which the service tube (7) houses electrical control or power cables, ventilated by air for cooling, these cables being arranged in a sheath, the service tube (7) preferably being configured to also accommodate oil, air or oiled air pipes.

9. Exhaust casing (0) according to claim 8, wherein the service tube (7) is configured to accommodate oil, air or oiled air lines.

10. Turbomachine comprising a turbomachine exhaust casing (0) according to one of claims 1 to 9.

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