EP3705686A1 - Turbine engine housing - Google Patents

Abstract

A casing (12) of a turbomachine turbine (11) comprising an inner shell (15), an outer shell (16) extending around the inner shell (15), and hollow arms (18) connecting the shell outer (16) to the inner shell (15) and each intended to receive a tubular easement element (21), each hollow arm (18) defining an internal housing (180) connecting a first passage opening (150) passing through the shell inside (15) in the radial direction (DR) to a second passage opening (160) passing through the outer shell (16) in the radial direction (DR), and having an internal wall (182) facing the internal housing (180 ). Each arm (18) includes at least one boss (185a, 185b, 1850a, 1850b) on said inner wall (182) of the arm (18) projecting from the inner wall (182) towards the inner housing (180) and defining a constriction (188, 1880) of the internal housing (180) in a section plane orthogonal to the direction in which the arm (18) extends.

Description

Technical area

The present invention relates to turbomachines, in particular aeronautical turbine engines, and more particularly to an aircraft turbomachine exhaust casing.

Prior art

A turbomachine exhaust casing generally includes an inner hub and an outer ferrule extending around the hub. The ferrule is configured to define with the hub an annular flow stream of a gas flow and is rigidly connected to the hub by arms which are substantially radial with respect to a longitudinal axis of the turbomachine. With reference to the flow of gases in the turbomachine, an exhaust casing is mounted downstream of a turbine and the flow of gas which passes through the exhaust casing is therefore the flow of exhaust gas leaving the turbine .

A turbomachine may include other similar casings such as an intermediate casing or an inter-turbine casing better known by its English designation TVF for “Turbine Vane Frame”, or even a TCF designating in English a “Turbine Center Frame”. An intermediate casing is interposed between a low pressure compressor and a high pressure compressor of the turbomachine, and is therefore crossed by a gas flow leaving the low pressure compressor and intended to supply the high pressure compressor.

The operation of a conventional turbomachine involves in particular the passage of electric cables and the circulation of various fluids through the turbomachine. By way of example, these fluids can be air, oil, or oiled air. In order to convey these fluids, it is known to have pipes in the very structure of the turbomachine. Some of these pipes, called service tubes, must connect radially external parts of the turbomachine to radially internal parts, and thus pass through the primary and secondary air flows.

It is known practice to pass service elements such as service tubes within hollow casing arms such as the hollow arms of an exhaust casing such as a structural exhaust casing such as a TVF, or else a non-structural exhaust casing such as a TRV (downstream turbine rectifier, or "Turbine Rear Vane" according to the English terminology generally used), or a TCF (inter turbine casing, or "Turbine Center Frame" according to the generally used Anglo-Saxon terminology).

The hollow arms of the exhaust casing thus allow the passage of ancillary elements, such as the ancillary tubes, without disturbing the flow of the flow inside the duct thanks to their internal cavity.

In general, each of the easement elements makes it possible to connect at least one first item of equipment located radially inside the duct to at least one second item of equipment located radially outside the duct of the casing.

On the figure 1 is illustrated an example of a part of an exhaust casing 1 of a turbomachine comprising a service element in the form of a tube 2 arranged inside a longitudinal cavity 3 provided inside a 'a hollow arm 4 connecting an internal hub 5 to an external ferrule 6 of the exhaust casing 1. The tube 2 is generally introduced within the longitudinal cavity 3 of the hollow arm 4 at the junction between the hollow arm 4 and the outer shell 6. The tube 2 is then slipped inside the cavity 3 until it fully extends therein. The tube 2 has two ends 8 and 9 which can be fixed respectively to the internal hub 5 and to the external ferrule 6 in order to secure the tube 2 to the internal hub 5 and to the external ferrule 6. The tube ends 8 and 9 are then assembled to tubes included in hydraulic or air circuits arranged in radially external or internal parts, so as to ensure fluid communication between radially external parts of the turbomachine and radially internal parts.

As shown on the figure 1 generally, over the majority of the length of the tube 2, the outer surface of the tube is not in contact with the longitudinal cavity wall 3. The tube 2 thus disposed is therefore free to vibrate.

However, the tube 2 has natural frequencies of vibration. Tube 2 vibrates most violently when excited at these frequencies. This induces rapid fatigue up to a break. These frequencies depend on the length of the tube 2, but also on the material which constitutes it, on its thickness, or on its temperature, among others. The longer the tube 2, the lower the natural frequency, the lower, and closer to the frequencies of rotation of the low and high pressure bodies of the turbomachine. These vibrations lead to problems of robustness and safety within the turbomachines. This is especially true in the case of large engines.

On high power engines, an auxiliary element such as the tube 2 generally comprises a longitudinal body defining an elongation axis and at least one stall damper inside the cavity, this damper making it possible in particular to avoid that the easement element does not resonate, and thus does not deteriorate, when it is subjected to the various vibratory stresses generated by the turbomachine in operation.

Various shock absorbers exist in the state of the art.

It is known, for example, to use two shock absorbers mounted head-to-tail, each in the form of a curved, flexible blade, and delimited laterally by flanks. Each blade comprises, on the one hand, a portion fixed to the body of the element, and on the other hand, a free portion. Each blade is positioned flat on the easement element, it extends along a transverse axis perpendicular to the elongation axis of the element and is configured to deform in a plane perpendicular to the axis elongation.

The easement element is configured to be mounted in the cavity in a direction substantially parallel to the axis of elongation of the element. During assembly, the free portions are constrained so that the latter each exert on a wall delimiting the cavity a return force necessary for the dampers to be able to fully perform their function.

The assembly / disassembly of the easement element presents some difficulties.

First, during the introduction of the easement element into the cavity, the sharp edges present on the sides of the dampers come into contact with the wall of the cavity and thus oppose its introduction. The operator is then obliged to operate by a back and forth movement and / or excessive force at the risk of damaging the shock absorbers and / or the wall of the cavity, and at the expense of productivity. The assembly is all the more critical because the free portions each exert a return force on the wall of the cavity.

Secondly, following the assembly and the difficulties encountered mentioned above, it generally proves impossible to disassemble the auxiliary element to carry out, for example, a maintenance operation without considerably damaging the shock absorbers and / or the wall of the cavity. .

Elastic return stiffeners are known from the document FR 3,064,302 and document FR 3,050,229 . They are used so that the natural modes of the ancillary elements on which they are mounted are not within the operating range of the turbomachine. These stiffeners have drawbacks similar to shock absorbers, in particular with respect to the sensitivity of the compression of the stiffeners during assembly. Indeed, the excessive compression of the latter during assembly can lead to their deterioration and therefore to the absence of contact between the stiffeners and the wall, thus rendering them ineffective.

It is also known from the document EP 0 342 087 a crankcase arm comprising a passage for an oil tube, the oil tube comprising a neck around which a clip is disposed in order to damp the vibrations occurring on the tube in operation.

It is also known from the document FR 3,061,928 a distributor blade comprising a support mast fixed to the casing and held inside the blade by a sleeve to minimize the forces operating on the mast.

Disclosure of the invention

The invention aims to overcome the above drawbacks and to overcome the difficulties mentioned above by proposing a turbomachine casing making it possible to ensure the support of the stiffeners or dampers of the auxiliary elements on the inner wall of its hollow arms. in a certain manner and without sensitivity to the assembly procedure, and more particularly by avoiding any compression of the stiffeners of the easement element during assembly.

An object of the invention provides a turbomachine casing, the casing having the shape of a ring defining an axial direction and a radial direction and comprising an inner shell, an outer shell extending around and away from the inner shell, and hollow arms connecting the outer shell to the inner shell and each intended to receive a tubular easement element, each hollow arm defining an internal housing connecting a first through hole passing through the inner shell in the radial direction to a second through hole through the outer shell in the radial direction, and having an inner wall delimiting the inner housing.

According to a general characteristic of the invention, each arm comprises at least one boss on said internal wall of the arm projecting from the internal wall towards the internal housing and defining a constriction of the internal housing in a section plane orthogonal to the direction in which the arm extends, said at least one boss being intended to cooperate with the tubular easement element, said at least one boss forming a support means of the tubular easement element.

Said at least one boss even preferably constitutes the sole means of support for the tubular easement element situated in the housing of the arm radially between the first and the second passage orifice.

Preferably, the constriction has in said section plane a passage section smaller than the section of said second passage orifice.

The internal arrangement of the arms with a boss makes it possible, firstly, to stiffen the maintenance of the easement element within the arm and thus to limit the risks of resonance.

The internal arrangement of the arms with a boss makes it possible, secondly, to provide stiffeners on the service tubes which are shorter and therefore stiffer and thus more effective in their role of dynamic stiffeners than the stiffeners known in the state of the art, because the distance between the tube and the arm is reduced locally and the operator does not have to deform the stiffeners himself, the stiffeners deforming without assistance during assembly of the tube along its axis.

Finally, the internal arrangement of the arms with a boss makes it possible, thirdly, to avoid any plasticization of the stiffeners during their compression during assembly. Indeed, the operator does not need to compress and plasticize the stiffeners during assembly, their width can easily be dimensioned.

In addition, having a section of the internal housing at the boss that is smaller than the section of the hollow arm at the orifice through which the easement element is introduced into the arm during its installation makes it possible to avoid any manipulation, such as 'compression, stiffeners when mounting the element of easements in the arm.

According to a first aspect of the housing, said at least one boss of each arm can be made of the same material as the arm with which it is associated.

The arm and said at least one boss can be made of metal or of Inconel 718® for example.

According to a second aspect of the casing, each arm may include a boss extending over at least half of the perimeter of said internal wall of the internal housing in said section plane orthogonal to the direction in which the arm extends, or at least a pair of bosses arranged opposite one another, to reduce the dimensions of the section of the passage of the throttle at least in one direction.

According to a third aspect of the casing, said at least one boss of each arm may extend, in the direction in which the arm extends between the inner shell and the outer shell, over a height of between 5 and 10 mm in order to constitute an effective support zone for the dampers or stiffeners of the easement element.

In a fourth aspect of the housing, said at least one boss of each arm may extend, in a direction orthogonal to the internal wall of the arm, over a thickness of between 1 and 10 mm.

In a fifth aspect of the housing, said at least one boss of each arm can be made in one piece with the arm to which it is associated.

In a sixth aspect of the housing, said at least one boss of each arm may form, in a section plane comprising the axial direction and the radial direction, a constriction of the internal housing of isosceles trapezoidal shape with the larger base disposed between the smaller base and the second through hole.

Such a form of boss allows compression of the stiffeners or shock absorbers of the easement element when it is fitted into the arm and when it is tightened with screws at its top, for example.

Alternatively, the edges between the large base and the small base may be fillets not having a flat surface.

When said at least one boss is made in a single piece with the arm, its machining makes it possible to compensate for the casting defects of the arms and of the bosses and thus to ensure the quality of the contact between the stiffeners of the easement element and the arms.

In a seventh aspect of the casing, said casing is an exhaust casing of a turbomachine turbine.

Another subject of the invention is a turbine comprising a casing as defined above.

Another subject of the invention is a turbomachine comprising a turbomachine turbine as defined above.

Another subject of the invention is an aircraft comprising at least one turbomachine as defined above.

Brief description of the drawings

• [ Fig. 1 ] The figure 1 already presented, illustrates an example of a part of an exhaust casing of a turbomachine comprising a service element.
• [ Fig. 2 ] The figure 2 is a first sectional view along a first sectional plane of a casing of a turbomachine according to one embodiment of the invention.
• [ Fig. 3 ] The figure 3 shows a second sectional view along a second sectional plane of the exhaust casing of the figure 1 .
• [ Fig. 4 ] The figure 4 shows a sectional view of an arm of the exhaust casing according to a first embodiment.
• [ Fig. 5 ] The figure 5 presents a zoom of the figure 4 at the boss of the arm.
• [ Fig. 6 ] The figure 6 shows a schematic sectional view of the exhaust housing arm of the figure 4 .
• [ Fig. 7 ] The figure 7 shows a schematic sectional view of the arm of the exhaust casing according to a second embodiment of the invention.

Description of embodiments

On the figure 2 is shown a first sectional view along a first sectional plane II-II of a casing 10 of a turbomachine 11 with double flow, the casing 10 comprising an exhaust casing 12 located between a low pressure turbine 13 and a nozzle 14 ejection of combustion gases from the turbine 13.

The turbomachine 11 defines an axial direction DA corresponding to the axis of revolution X of the turbomachine 11 and the axis of rotation of the low pressure turbine 13, and a radial direction DR. The first section II-II of the turbomachine 11 on the figure 2 includes the axial direction DA and the radial direction DR.

Throughout this text, the terms “inside” and “outside” or “inside” and “outside” are used with reference to the position or orientation in the radial direction DR with respect to the axis of revolution X of the turbomachine 11.

On the figure 3 is shown a second sectional view along a second section plane III-III of the casing 10 of the turbomachine of the figure 2 . The second section plane III-III is orthogonal to the axial direction DA and includes the radial direction DR. The second section plane III-III is located in the free space between the low pressure turbine 13 and the exhaust casing 12.

As shown on the figures 2 and 3 , the exhaust casing 12 comprises an inner shell 15 and an outer shell 16 extending around and away from the inner shell 15. The outer shell 16 is configured to define with the inner shell 15 an annular flow stream 17 a flow of combustion gas F. The exhaust casing 12 further comprises arms 18 rigidly connecting the outer shell 16 to the inner shell 15. The arms 18 extend mainly in the radial direction DR relative to the axis of revolution X of the turbomachine 11.

The illustrated embodiment is in no way limiting, the turbomachine 11 may include other casings having a similar structure, and thus the exhaust casing 12 could be for example an intermediate casing located between a low pressure compressor and a compressor. high pressure (not visible on the figure 2 ).

In the embodiment illustrated in figures 2 and 3 , the exhaust casing 12 comprises a plurality of hollow tubular arms 18 each allowing the passage of an auxiliary element 21.

The passage of the auxiliary elements 21 in the arms 18 has the particular advantage of not disturbing the flow of the gas flow F inside the duct 17, that is to say of avoiding losses of gas. charge. An easement element 21 connects at least a first item of equipment located radially inside the stream 17 to at least one second item of equipment located radially outside the stream 17. Such an element 21 may for example comprise one or more several air ducts and / or one or more oil ducts and / or one or more electric cables, etc.

On the figure 4 is illustrated a sectional view of an arm 18 of the exhaust casing 12 according to a first embodiment.

The arm 18 has a length in a substantially radial direction DR, a width in the axial direction DA and a thickness in a circumferential direction DC. The length of the arm is greater than the width of the arm which is greater than its thickness. The arm 18 thus has a hollow blade shape, the blade extending mainly in a plane comprising the radial direction DR and the axial direction DA and having a thickness along the circumferential direction DC.

The tubular arm 18 comprises a cavity 180 extending substantially radially between the inner shell 15 and the outer shell 16. The cavity 180 is delimited by an inner wall 182 of the arm 18. The cavity 180 opens out both on the inner shell 15. via a first passage orifice 150 and on the outer shell 16 via a second passage orifice 160. The internal wall 182 comprises two parts 182a, 182b extending opposite one another.

As shown on the figure 4 as well as on the figure 5 which is a zoom of a portion of the arm 18 of the figure 4 , each arm 18 comprises two bosses 185 arranged facing each other and separated by a free space extending in the circumferential direction DC. A first boss 185a is made on the first inner wall part 182a while the second boss 185b is made on the second inner wall part 182b. The two bosses 185a and 185b are made in the middle of the arm 18, namely midway between the inner shell 15 and the outer shell 16.

On the figure 6 is shown a schematic sectional view of the exhaust housing arm of the figure 4 . As shown on figures 4 and 6 , in a direction orthogonal to the planes in which the two bosses 185a and 185b extend, in other words in a direction orthogonal to two parallel planes tangent or coincident with the two wall parts 182a and 182b of the arm 18, the two bosses 185a and 185b define a passage of dimension smaller than the dimension in the same direction of the passage formed by the second passage opening 160 of the outer shell 16.

The two bosses 185a and 185b thus form a constriction 188 of the cavity 180 in the middle of the arm 18 makes it possible to ensure contact between a stiffener 210 of a support element 21 and the internal wall 182 of the arm 18 at at least one height. of the arm 18, that of the bosses 185a and 185b. The distance between the easement element 21 and the internal wall 182 being reduced to this height thanks to the bosses of the stiffeners 210 provided on the easement elements 21 can be shorter than in the state of the art and thus stiffer, which improves their efficiency in their role of dynamic stiffener.

In a variant, the two bosses 185a and 185b could be formed by the same boss produced over the entire perimeter of the internal wall 182.

On the figure 7 is shown a schematic sectional view of the arm 18 of the exhaust casing 12 according to a second embodiment of the invention.

In the second embodiment illustrated in figure 7 , the two bosses 1850a and 1850b of each arm 18 form, in a section plane comprising the axial direction DA and the radial direction DR, a constriction 1880 of the cavity 180 of isosceles trapezoidal shape with the larger base disposed between the base the smallest and the second through hole. In other words, the largest base is arranged radially on the outside of the smaller base to facilitate insertion of the arm from the outside.

As shown on the figure 7 , each boss 1850a and 1850b has a generally triangular shape in a section plane orthogonal to the axial direction DA, and more particularly the shape of a right triangle, with one of the sides forming a right angle with the internal wall 182, a first end of its hypotenuse 1852 oriented towards the constriction 1880, that is to say towards the element of easements 21, and the second opposite end of the hypotenuse which forms a point is oriented radially outwards from the constriction 1880 and to the second passage orifice 160 made in the outer shell 16.

The slope of the triangular shape of the boss 1850 allows compression of the stiffeners 210 of the easement element 21 easier when it is fitted into the arm and to compensate for the casting defects of the arms 18 and of the bosses 1850a and 1850b and so on. 'ensure the quality of the contact between the stiffeners 210 of the easement element 21 and the arm 18.

The invention thus provides a turbomachine casing making it possible to ensure the support of the stiffeners or shock absorbers of the auxiliary elements on the inner wall of its hollow arms in a certain manner while facilitating assembly, and more particularly by avoiding any damage by compression. stiffeners of the easement element during assembly.

Claims (10)

Turbomachine casing (11), the casing (12) having the shape of a ring defining an axial direction (DA) and a radial direction (DR) and comprising an inner shell (15), an outer shell (16) s' extending around and away from the inner shell (15), and hollow arms (18) connecting the outer shell (16) to the inner shell (15) and each intended to receive a tubular easement element (21), each arm (18) hollow defining an internal housing (180) connecting a first through hole (150) passing through the inner shell (15) in the radial direction (DR) to a second through hole (160) through the outer shell (16) in the radial direction (DR), and comprising an internal wall (182) delimiting the internal housing (180),
characterized in that each arm (18) comprises at least one boss (185a, 185b, 1850a, 1850b) on said inner wall (182) of the arm (18) projecting from the inner wall (182) towards the inner housing (180) and defining a constriction (188, 1880) of the internal housing (180) in a section plane orthogonal to the direction in which the arm (18) extends, said at least one boss being intended to cooperate with the tubular easement element (21), said at least one boss (185a, 185b, 1850a, 1850b) forming a support means of the tubular easement element (21). Housing (12) according to claim 1, wherein said at least one boss (185a, 185b, 1850a, 1850b) of each arm (18) is made of the same material as the arm (18) with which it is associated. Housing (12) according to one of claims 1 or 2, each arm comprising a boss extending over at least half of the perimeter of said internal wall (182) of the internal housing (180) in said section plane orthogonal to the direction in which the arm (18) extends, or at least a pair of bosses (185a, 185b, 1850a, 1850b) arranged opposite each other, to reduce the dimensions of the section of the passage of the 'choke (188, 1880) in at least one direction. Housing (12) according to one of claims 1 to 3, wherein said at least one boss (185a, 185b, 1850a, 1850b) of each arm (18) extends, in the direction in which the arm (18) extends between the inner shell (150) and the outer shell (160), over a height of between 5 and 10 mm. Housing (12) according to one of claims 1 to 4, wherein said at least one boss (185a, 185b, 1850a, 1850b) of each arm (18) extends, in a direction orthogonal to the inner wall (182 ) of the arm (18), to a thickness of between 1 and 10 mm. Housing (12) according to one of claims 1 to 5, wherein said at least one boss (185a, 185b, 1850a, 1850b) of each arm (18) is made in one piece with the arm (18) to which it is associated. Housing (12) according to one of claims 1 to 6, wherein said at least one boss (1850a, 1850b) of each arm (18) forms, in a section plane comprising the axial direction (D _A ) and the direction radial (D _R ), a constriction (1880) of the internal housing (180) of isosceles trapezoidal shape with the larger base disposed between the smaller base and the second passage opening (160). A housing (12) according to any one of claims 1 to 7, wherein said housing is an exhaust housing of a turbomachine turbine. Turbine comprising a casing (12) according to one of claims 1 to 8. Turbomachine (11) comprising a turbine according to claim 9.

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