TURBOMACHINE COMPRISING A COOLING AIR CAVITY AND A DETACHMENT DEVICE

Abstract

The invention relates to a turbomachine (1) comprising a stator (2) centered on the longitudinal axis (X), a rotor (3) comprising at least one disk (4) being driven in rotation about the longitudinal axis (X) by a drive shaft (5), the disk (4) being fixed to the drive shaft (5) by at least one bolted connection (10, 35), and an annular cavity (45), delimited at least partially by the drive shaft (5) and the disk (4), and being adapted to be supplied with cooling air via an ejection element (50) which is disposed substantially opposite the bolted connection (10, 35). According to the invention, the drive shaft (5) is provided with a deflector element (55) which is configured to deflect the cooling air away from the bolted connection (10, 35). Figure for the abstract: Fig. 2

Description

Title of the invention: TURBOMACHINE COMPRISING A COOLING AIR CAVITY AND A DETACHMENT DEVICE Technical field of the invention

[0001] The present invention relates to the field of aircraft turbomachinery. More specifically, the invention relates to turbomachinery equipped with a cavity through which cooling air circulates. Technological background

[0002] Turbomachinery generally comprises at least one stator and one rotor arranged along an axis of rotation of the turbomachine. The stator comprises a row of fixed blades attached to housings by means of platforms or ferrules, and the rotor comprises an annular row of movable blades, each extending from a disk. Each disk is driven in rotation by a drive shaft centered on the axis of rotation. The disks are attached to the drive shaft via flanges and bolts, for example. The drive shaft is supported by at least one bearing that serves as an interface with the stator of the turbomachine.

[0003] The fixed and moving blades, as well as the discs, are traversed by flows of "hot" air at a very high temperature. It is known to provide cavities through which a cooling airflow circulates to cool components subjected to high thermal stresses, such as the discs, thereby preventing damage to them. These cavities are arranged under the discs for this purpose.

[0004] Figure 1 shows an example of a cavity A located under a rotor disc B C. Cooling air D, from a relatively cooler area, is ejected into the cavity A through a labyrinth seal E, for example, at a very high speed. The cooling air D is violently projected onto the walls of the cavity A formed by the drive shaft F, the ferrules G, and the walls of the disc B. The flanges and bolts forming bolted connections H, I extend at least partially into the cavity A. The bolted connection H forms a rotating obstacle inside the cavity A. This generates, on the one hand, viscous heating which can affect the thermal resistance of the cavity A and, on the other hand, pressure variations in the cavity A when the cooling air is in motion, which can generate acoustic / vibrational excitation in the cavity.In particular, there are strong pressure variations at the bolted H connection when cooling air circulates in the cavity.

[0005] There is a need to resolve all or part of the aforementioned drawbacks. Summary of the invention

[0006] The objective of the present invention is to provide a simple and economical solution for reducing or even eliminating viscous losses and acoustic excitations in a cooling air cavity.

[0007] We achieve this objective in accordance with the invention by means of a turbomachine comprising: - a stator centered on the longitudinal axis, - a rotor comprising at least one disc being driven in rotation around the longitudinal axis by a drive shaft, the disc being fixed to the drive shaft by at least one bolted connection, and - an annular cavity, delimited at least in part by the drive shaft and the disc, and being suitable for being supplied with cooling air via an ejection element which is disposed substantially opposite the bolted connection, the drive shaft being provided with a deflection element which is configured so as to deflect the cooling air from the bolted connection.

[0008] Thus, this solution makes it possible to achieve the aforementioned objective. In particular, the arrangement of a deflector device in the cavity is simple to design, implement, and inexpensive. The deflector device reduces the pressure in the cavity and redirects the cooling air upstream of the cavity so as to prevent the cooling air from coming into direct contact with a bolted connection located downstream of the deflector device, which rotates with the turbomachine rotor. Furthermore, the installation of this deflector device requires few or no structural modifications.

[0009] The turbomachine also comprises one or more of the following features, taken alone or in combination:

[0010] - the deflection member is arranged axially between the ejection element and the linkage bolted.

[0011] - the deflection member extends radially inside the cavity.

[0012] - the deflection organ is annular.

[0013] - the deflection member and the drive shaft are formed from a single piece.

[0014] - the deflection member has a vertex which is arranged radially inside of an axis of the bolted connection.

[0015] - the deflection member has a vertex which is arranged radially on the outside of an output axis of the ejection element.

[0016] - the deflection member has an inclination with respect to a radial axis which forms an angle between 50° and 80°.

[0017] - the turbomachine includes a labyrinth seal disposed upstream of the element ejection following the circulation of the cooling air

[0018] - - the drive shaft is supported by the stator via at least one bearing.

[0019] — the deflection member has a curved, concave surface, which is oriented towards the ejection element.

[0020] The invention also relates to an aircraft equipped with such a turbomachine. Brief description of the figures

[0021] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent upon reading the following detailed explanatory description, of embodiments of the invention given by way of purely illustrative and non-limiting examples, with reference to the accompanying schematic drawings in which:

[0022] - Figure 1 illustrates a partial axial cross-section of an example of a turbomachine including a cavity in which cooling air circulates according to the prior art;

[0023] - Figure 2 is a partial axial cross-sectional view of an example of a turbomachine equipped with a device for diverting cooling air into a cavity according to the invention;

[0024] - Figure 3 illustrates in detail a portion of a drive shaft equipped with a a device for diverting cooling air according to the invention; and

[0025] - Figure 4 schematically represents the displacement of an air of cooling in a cavity in which a deflection device according to the invention is arranged. Detailed description of the invention

[0026] The [Fig.1] has been described in the preceding.

[0027] In this description, identical or substantially identical elements and / or elements with the same functions are represented by the same numerical references.

[0028] Figure 2 partially represents a turbomachine 1 intended to be mounted on a spacecraft. The spacecraft may be an aircraft comprising, for example, a fuselage and two wings extending on either side of the fuselage relative to the fuselage axis; each wing being able to carry at least one turbomachine.

[0029] The turbomachine 1 may be a turbojet or a turboprop. The turbomachine may include a propeller or a fan that is enclosed or unenclosed.

[0030] The turbomachine 1 has a longitudinal axis X, which is here the axis of rotation of the rotors of the turbomachine.

[0031] In the present invention, and more generally, the terms "upstream," "downstream," "axial," and "axially" are defined with respect to the gas flow in the turbomachine and with respect to the longitudinal axis X of the turbomachine. Similarly, the terms "radial," "radially," "internal," and "external" are defined with respect to a radial axis Z perpendicular to the longitudinal axis X and with respect to the distance from the longitudinal axis X.

[0032] In [Fig.2], the turbomachine 1 comprises at least one stator 2 and one rotor 3 which are arranged along the longitudinal axis X. The turbomachine 1 may comprise several stators 2 and rotors 3 which alternate along the longitudinal axis X. A stator 2 and a rotor 3 may constitute one stage of a component of the turbomachine 1, such as a low-pressure or high-pressure compressor or a low-pressure or high-pressure turbine. In the example shown, a stator 2 is mounted upstream of the rotor 3.

[0033] Each rotor 3 can include one or more discs 4 connected to a drive shaft 5 of the turbomachine 1. The drive shaft 5 can be a low pressure shaft or a high pressure shaft.

[0034] Each rotor 3 comprises at least one rotor blade 6 (or moving blade) extending from a disk 4. Advantageously, but not limitingly, several rotor blades 6 are distributed regularly around the longitudinal axis X.

[0035] Following a non-limiting embodiment, each rotor blade 6 comprises a foot and a blade extending radially from the foot. Each disc 4 may comprise several recesses formed at the periphery of the disc 4 and intended to receive a foot of a rotor blade 6.

[0036] Following another non-limiting embodiment, the disc 4 and the rotor blades 6 are monoblocs. That is to say, they form a single piece. The rotor blades 6 and the disc 4 may be machined from a single piece of material, or the rotor blades 6 may be welded onto the disc 4.

[0037] The various discs 4 can be fixed together. As shown in [Fig. 2], each disc 4 advantageously comprises a first annular leg 7 extending substantially along the longitudinal axis X. Here, the first leg 7 shown extends downstream from a downstream face 8. Each first leg 7 comprises, for example, a flange 9 which is annular and advantageously extends radially. Preferably, each flange 9 extends towards the longitudinal axis X.

[0038] The flange 9 is connected, for example, to a flange (not shown) of another adjacent disk located downstream, for example, by a bolted connection 10, referred to as the upper bolted connection 10. The flange of the adjacent disk (not shown) is connected to a second tab extending from an upstream face 11 of the adjacent disk.

[0039] Following a non-limiting embodiment, each disc 4 comprises a first leg 7 downstream and a second leg upstream, each with a flange. The flanges and adjacent flanges are connected in pairs by a bolted connection 10.

[0040] Each upper bolted connection 10 advantageously, but not limited to, includes at least one threaded rod 12 which passes through coaxial holes 13 in the flanges 9. Each hole 13 advantageously passes through a flange 9 on either side along an axis 14. In this example, the latter is parallel to the longitudinal axis X of each flange 9. At least one bolt 15 or nut is provided for tightening the flanges 9 together.

[0041] Advantageously, the drive shaft 5 drives at least one disk 4 in rotation around the longitudinal axis X. The drive shaft 5 is for example supported by the stator 2 via at least one bearing 17 and the disk 4 is fixed on the drive shaft 5 by at least the upper bolted connection 10.

[0042] By way of example, the bearing 17 comprises an inner ring and an outer ring. Rolling elements (preferably balls) are arranged between the inner ring and the outer ring.

[0043] Optionally, the inner ring is attached to the drive shaft 5 and the outer ring is attached to a ferrule 19 (acting as a bearing support) connected to the stator 2.

[0044] Each stator 2 includes for example a radially internal platform 20 from which extends at least one stator blade 21 (or fixed blade).

[0045] In the present description, a "stator blade" is a blade that is not driven in rotation around the longitudinal axis X of the turbomachine 1. The stator blade may have variable pitch.

[0046] The ferrule 19 includes for example a radial flange 22 which is fixed to the radially internal platform 20 and an axial portion 23 to which the outer ring of the bearing 17 is attached. The radial flange 22 is advantageously attached to an upstream face 24 of the radially internal platform 20.

[0047] A flange 26 is advantageously mounted on a downstream face 27 of the radially internal platform 20. The flange 26 comprises, for example, a first portion 28 extending radially and fixed to the radially internal platform 20. The flange 26 comprises, for example, a second portion 29 which extends substantially (possibly with an inclination, for example, of the order of 20°) along the longitudinal axis from the first portion 28. The second portion 29 comprises, for example, a free end 30 which is arranged opposite the disk 4, and preferably opposite the upstream face 11.

[0048] Advantageously, but not limitingly, the drive shaft 5 comprises a first trunnion 32 which is annular and which extends along the axis longitudinal X. The inner ring of the bearing 17 is mounted at a first end 32a of the first journal 32. The first journal 32 includes a first flange 33 at a second end 32b (which is opposite the first end 32a along the longitudinal axis X). The first flange 33 extends radially and preferably outwards.

[0049] Following an example of an embodiment, the first trunnion 32 extends globally by flaring out from its first end 32a to its second end 32b.

[0050] Advantageously, but not exclusively, the drive shaft 5 includes a second journal 34 that connects the first journal 32 to the discs 4. The second journal 34 is advantageously connected to the first journal 32 by means of a bolted connection 35, referred to as the lower bolted connection 35. In particular, the second journal 34 includes at a first end 34a a second flange 36 that extends radially and preferably inwards. The first and second flanges 33, 36 respectively include a through hole 37 on either side. Each orifice 37 has an axis 38 which is preferably parallel to the longitudinal axis X. A threaded rod 39 passes through the orifices 37. Nuts 40 are advantageously mounted on the threaded rod 39 on either side of the first and second flanges 33, 36 so as to tighten them against each other.

[0051] According to an optional feature, the axis 38 of each lower bolted joint 35 is located radially inside the axis 14 of each upper bolted joint 10.

[0052] The second trunnion 34 is connected to the discs, for example, via the upper bolted connection 10. The second trunnion 34 comprises, at a second end 34b (opposite to the first end 34a along the longitudinal axis X), a third flange 41 extending radially and preferably outwards. The fourth flange 41 comprises at least one orifice 42 passing axially through it on both sides and through which the threaded rod 12 passes.

[0053] The second trunnion 34 optionally includes a section of substantially frustoconical shape.

[0054] The turbomachine 1 comprises a cavity 45 which is arranged radially inside at least one disk 4. The cavity 45 is advantageously annular. In the present example, the cavity 45 is delimited at least in part by the drive shaft 5 and the disk 4. More precisely, and in the case of the illustrated example, the cavity 45 is delimited by the first journal 32, the second journal 34, the lower bolted joint 35, the upper bolted joint 10, the disk 4 with its first lug 7, the flange 26 and the ferrule 19.

[0055] According to an advantageous feature, cooling air is able to circulate in the cavity 45 so as to cool at least the disk 4 and limit the gradients thermal. Advantageously, the cooling air is drawn from the high-pressure or low-pressure compressor. The turbomachine 1 includes for this purpose a ventilation circuit (not shown) which is coupled at the high-pressure or low-pressure compressor and to cavity 45, and through which the cooling air circulates.

[0056] A sealing device 46 is optionally arranged between the stator 2 and the rotor 3. Preferably, the sealing device 46 is arranged between the ferrule 19 and the drive shaft 5. The sealing device 46 comprises, for example, a labyrinth seal 47 (advantageously comprising flaps or blades). According to this embodiment, the labyrinth seal 47 is located downstream of the bearing 17.

[0057] Advantageously, the cooling air is ejected into the cavity 45 via at least one ejection element 50. The labyrinth seal 47 is advantageously, but not exclusively, arranged upstream of the ejection element 50. The cooling air leaves the cavity 45 through a space formed between the upstream face 11 of the disc and the free end 30 of the second portion of the ferrule 19.

[0058] According to one embodiment, the ejection element 50 is arranged substantially opposite at least one bolted connection, and preferably opposite the lower bolted connection 35 which extends radially inside the cavity 45.

[0059] The ejection element 50, for example, has an ejection axis 51 that is substantially parallel to the longitudinal axis X. Advantageously, but not exclusively, the ejection element 50 is in the form of a passage section extending around the longitudinal axis X and is annular (extending over 360°). Alternatively, the ejection element 50 comprises one or more orifices, each opening into the cavity 45.

[0060] Optionally, the cooling air is supplied from at least one opening 49 which passes radially through the drive shaft 5 on both sides. The opening or openings 49 preferably open into the cavity 45 and upstream of the ejection element 50.

[0061] With further reference to [Fig. 2], the drive shaft 5 is provided with at least one deflector 55 which is configured to deflect the cooling air away from at least the lower bolted connection 35. Any bolted connections present in the cavities can become obstacles to the cooling air if the airflow is not controlled.

[0062] Advantageously, the deflector 55 extends radially inside the cavity 45 and is arranged upstream of the lower bolted connection 35. Preferably, the deflector 55 is arranged axially between the ejection element 50 and the lower bolted connection 35. In this way, the cooling air circulating in cavity 45 does not in particular impact the lower bolted connection 35. The cooling air does not directly impact the upper bolted connection 10 either.

[0063] More specifically, the deflection member 55 is supported by the first journal 32, which partially forms the upstream ejection element 50 and includes the downstream first flange 33. The deflection member 55 advantageously extends from an external surface 48 of the first journal 32.

[0064] Optionally, the deflection member 55 extends substantially radially between a base 55a and a vertex 55b (visible in [Fig. 3]). The base 55a is, for example, connected to the drive shaft 5.

[0065] Advantageously, the deflection member 55 is formed as a single piece with the drive shaft 5, and preferably with the first journal 32. This simplifies manufacturing and saves assembly time. To this end, the drive shaft 5 and the deflection member 55 can be produced by an additive manufacturing process. Preferably, but not exclusively, the additive manufacturing process can be a laser melting process known by the English acronym SLM for "Selective Laser Melting," which allows the powder of the material intended to produce the drive shaft 5 with the deflection member 55 to be melted.

[0066] Alternatively, the drive shaft 5 and the deflection member 55 can be produced by a molding process.

[0067] According to yet another alternative, the drive shaft 5 and the deflection member 55 can be produced by a casting process.

[0068] The deflection member 55 could be manufactured separately and attached to the drive shaft. In this case, the deflection member 55 could itself be manufactured by a molding, casting, or additive manufacturing process. The deflection member 55 could be attached using fasteners such as, but not limited to, screws, bolts, etc.

[0069] The drive shaft 5 and the deflection member 55 can be made of a metallic material or a metallic alloy. Examples of metallic materials or metallic alloys may be known by the trade names DS200, Inconel®, AMI, and René 77®. Such materials can withstand the high temperatures prevailing within the cavity 45.

[0070] Advantageously, but not exclusively, the deflection member 55 is annular. This configuration allows all the cooling air to be directed upstream of the cavity 45, i.e. away from the lower bolted connection 35.

[0071] The radial position and / or the axial position of the deflection member 55 is / are a function of the environment and the geometric configuration of the surrounding parts.

[0072] In the example shown, the apex 55b of the deflection member 55 is arranged radially inside the axis 38 of the lower bolted joint. The apex 55b is, for example, inscribed in a circle 56 whose diameter is smaller than the diameter bounded by the axis or axes 38 of the lower bolted joint 35. This configuration allows access to the lower bolted joint 35 for maintenance purposes. The lower bolted joint 35 is typically located downstream of a tightening key.

[0073] According to another advantageous feature, the apex 55b is arranged radially outside the outlet axis 51 of the ejection element 50. The diameter of the circle 56 is greater than the diameter formed by the outlet axis 51 of the ejection element. This allows the cooling air to come into direct contact with the deflecting member 55.

[0074] The deflector 55 can be positioned at a predetermined distance d4 from the first flange 33. Preferably, the predetermined distance d4 is measured between a median axis 57 (parallel to the radial axis) of the deflector 55 and a plane PI in which a downstream surface 58 of the first flange 33 is defined. The predetermined distance d4 is between 35 mm and 70 mm, and preferably 50 mm. The predetermined distance d4 allows for better deflection of the cooling air and ensures that the deflector does not interfere with the assembly of adjacent parts such as flanges and bolts. Naturally, the predetermined distance is adapted and optimized according to the dimensions of the cavity.

[0075] In [Fig. 3], the deflection element 55 is inclined with respect to the longitudinal axis X. The angle of inclination α is measured, for example, with respect to the longitudinal axis X and is, for example, between 50° and 80°. Preferably, the angle of inclination α is 70°. The angle of inclination α advantageously contributes to the redirection of the cooling air upstream of the cavity.

[0076] Advantageously, but not limitingly, the deflection member 55 has a curved, concave surface 55c, which is oriented towards the ejection element 50. The curved surface 55c connects the base 55a to the apex 55b.

[0077] Figure 4 schematically illustrates the effect of the deflector 55 (shown schematically) on the cooling air in the cavity 45. The cooling air exiting the ejection element 50 is directed onto the deflector 55, which diverts it and prevents it from flowing towards the lower bolted connection 35. Some of the cooling air flows towards the upper bolted connection 10, but at a lower velocity. Area 45a represents a cooling air flow to the right. Areas 45c and 45d represent a cooling air flow to the left. The cooling airflow circulates primarily and advantageously around a zone 45b of cavity 45.

[0078] In this way, the arrangement of a simple deflection member 55 on the path of the cooling air at the outlet of the ejection element eliminates pressure variations and limits the power in the cavity 45 under the disc.

Claims

Demands

1. Turbomachine (1) comprising: - a stator (2) centered on the longitudinal axis (X), - a rotor (3) comprising at least one disk (4) being driven in rotation about the longitudinal axis (X) by a drive shaft (5), and the disk (4) being fixed on the drive shaft (5) by at least one bolted connection (10, 35), and - an annular cavity (45), delimited at least in part by the drive shaft (5) and the disk (4), and being capable of being supplied with cooling air via an ejection element (50) which is disposed substantially opposite the bolted connection (10, 35), characterized in that the drive shaft (5) is provided with a deflector element (55) which is configured so as to deflect the cooling air from the bolted connection (10, 35).

2. Turbomachine (1) according to claim 1, characterized in that the deflection member (50) is arranged axially between the ejection element (50) and the bolted connection (10, 35).

3. Turbomachine (1) according to any one of claims 1 and 2, characterized in that the deflection member (55) extends radially inside the cavity (45).

4. Turbomachine (1) according to any one of claims 1 to 3, characterized in that the deflection member (55) is annular.

5. Turbomachine (1) according to any one of claims 1 to 3, characterized in that the deflection member (55) and the drive shaft (5) are formed in one piece.

6. Turbomachine (1) according to any one of the preceding claims, characterized in that the deflection member (55) has a vertex (55b) which is arranged radially inside an axis (38) of the bolted connection (35).

7. Turbomachine (1) according to any one of the preceding claims, characterized in that the deflection member (55) has a vertex (55b) which is arranged radially outside an output axis (51) of the ejection element (50).

8. Turbomachine (1) according to any one of the preceding claims, characterized in that the deflection member (55) has an inclination with respect to a radial axis which forms an angle between 50° and 80°. 12

9. Turbomachine (1) according to any one of the preceding claims, characterized in that it comprises a labyrinth seal (47) disposed upstream of the ejection element (50) following the flow of the cooling air.

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