Variable timing crankcase treatment using coaxial multi-discs

Abstract

The invention relates to an axial compressor for an aeronautical turbomachine comprising at least one rotor wheel adapted to rotate about an axis of rotation (X) and a housing situated around the rotor wheel. The housing is provided internally with discs (25) in contact with the fluid, individually arranged perpendicular to the axis of rotation and mounted to rotate relative to each other about the axis of rotation. By means of actuation means (37), slots (31) in the discs can be oriented axially or obliquely with respect to the axis of rotation (X). Figure to be published with the abstract: [Fig. 14]

Description

Title of the invention: Variable timing casing treatment using coaxial multi-discs Technical field of the invention

[0001] The invention relates to a casing treatment for an aeronautical turbomachine designed to control the fluid (gaseous) flow at the tips of the blades of a rotating wheel, or rotor wheel. More particularly, the invention relates to a compressor casing of this turbomachine and to a compressor of the turbomachine.

[0002] In other words, the invention relates to the passive control of the aforementioned gas flow via the technology of "crankcase treatments", also called end-wall treatments.

[0003] The gaseous fluid flowing globally from upstream to downstream in an aeronautical turbomachine, the "casing treatments" (understood to mean stator casing) consist of local modifications in the shape of the external envelope of the aerodynamic duct, limited by the casing, around the rotor wheels, and therefore around the axis of rotation of (each) rotor wheel.

[0004] In this text, "axial" means along, or parallel to, the axis (X below) of rotation or revolution of a rotor element of the turbomachine, i.e., of the aforementioned rotor wheel, and "radial" means radially (perpendicularly) to this axis of rotation, which is also the axis of the compressor(s) and turbine(s). "Axial rotation" means rotation about said axis. Prior art

[0005] During the operation of an aeronautical turbomachine, typically a compressor comprising at least one rotor wheel equipped with blades and rotating in a casing forming the outer envelope of the fluid stream to be moved and compressed, a large fluctuation in the fluid flow in the compressor can occur, called compressor sloshing.

[0006] It is known that using crankcase treatments of the "axial slots" type makes it possible to locally modify the gas flow in the fluid stream and thus influence the onset of mechanisms responsible for compressor surge. An effective crankcase treatment can increase the compressor's performance operating range by delaying the onset of these mechanisms, in particular by reducing aerodynamic blockage at the rotor wheel tip.

[0007] Housing treatments of the "axial slots" type typically comprise a series of slots arranged along the radially inner circumference of the housing (in the azimuthal direction) and, radially, around a rotor wheel of the com- presser.

[0008] These treatments are non-axisymmetric with respect to the compressor's axis of rotation. They are therefore frequently referred to as Non-Axisymmetric Crankcase Treatment (or NAC).

[0009] Thus, in the present document, a local interior surface, defined by the structural parts that delimit these slots (i.e., by the disks discussed below), will be non-axissymmetric, since a cross-section along a plane perpendicular to the axis of rotation will not be circular. More precisely, such a surface will be locally non-axissymmetric because, along the aforementioned radially interior circumference (of each disk), the radius of said surface at the level of the area considered will vary according to the angle that this radius forms with a vertical axis perpendicular to the X-axis of revolution.

[0010] The effectiveness of an axial slot casing treatment depends on the suitability of the slot orientation to the flow shape as it approaches the pumping zone. Depending on the compressor's rotational speed, the flow shape changes (typically subsonic at partial speed and supersonic at high speed), and therefore the optimal slot orientation is not the same. Similarly, the optimal orientation of the upstream portion of the slots is not necessarily the same as the optimal orientation of the downstream portion. Simple shapes (straight slots) are therefore not always the best solution for various operating conditions. A casing treatment with curved slots, also called an arc casing treatment, has also been proposed, where the upstream portions of the slots do not have the same alignment as the downstream portions.

[0011] The respective positions of the upstream and downstream portions of the same slot can be adapted relative to the blade tip flow according to the operating regime of the turbomachine. The relative orientation of the flow with respect to the axially rotating blade is indeed different depending on the regime. The upstream / downstream angles are, however, usually chosen with respect to the flow at an operating point. Ideally, it would be possible to adapt these slot angles according to each operating regime. However, the constraints of integrating the slots into the housing and controlling the orientation remain major difficulties. Presentation of the disclosure

[0012] The following disclosure aims to overcome such major difficulties and, to this end, applies to an axial compressor of an aeronautical turbomachine comprising: - at least one rotor wheel adapted to rotate about an axis of rotation of the compressor, in a channel where a fluid can flow, and - a housing located around the rotor wheel.

[0013] More specifically, the present disclosure proposes that this axial compressor include a TCNA and be such: - that the casing is internally equipped, around the rotor wheel, with a plurality of discs with which the fluid can come into contact and which: — are coaxial with the axis of rotation, — are arranged individually perpendicular to the axis of rotation, — are arranged one after the other along the axis of rotation, — are mounted to rotate relative to each other and to the housing, around the axis of rotation, each disk of the plurality of disks defining an internal circumference around the axis of rotation, and having a plurality of notches distributed around the circumference, and - that the compressor further comprises means for actuating the discs, adapted to drive said discs (i.e., at least some of them) together around the axis of rotation, the induced rotation of at least one disc relative to the other discs of the plurality of discs allowing the shape of slots individually created by a series of notches of the plurality of notches situated one after the other along the axis of rotation to be modified, such that each slot can be presented as: — an axial slit, or — a slit oriented obliquely with respect to the axis of rotation, in a plane (PI below) passing through the slit and parallel to the axis of rotation.

[0014] Thus, we will have a TCNA casing treatment with slots and variable shimming, this shimming being obtained by a coaxial multi-disc solution.

[0015] By means of such discs attached to the housing, structurally independent of the housing, their notches, their capacity for relative movement around the axis of rotation, and the means for actuation of the discs, we have: - a simple solution for the functional integration of the slots "into" the housing, - of a casing that retains its integrity, - a modular solution offering a wide range of adaptability regarding the desired shape of the slots, and - a solution for controlling the orientation of these slots, which can therefore be axial or oblique.

[0016] Regarding this control of the orientation of the slots, it is proposed: - that the disks of the plurality of disks being arranged successively, along the axis of rotation, from a first disk to a last disk, - that the discs and the means of actuation of the discs are adapted to drive, in the said oblique orientation, all in common, the said discs around the axis of rotation, at an angle with respect to a parallel to the axis of rotation which is as more important than considering said discs, from the first to the last.

[0017] Thus, it will be possible to ensure that each slot has a variable, progressive curvature, in one direction or the other, depending on the direction of rotation of the compressor blades.

[0018] The aeronautical turbomachine under consideration may be enclosed. But it could also be unenclosed; in other words, of the open-rotor type: Whether the engine is enclosed or not does not change the aerodynamics of the aforementioned axial compressor.

[0019] A synonym for the aforementioned expression "discs" or "plurality of discs" is "rings" or "plurality of rings". The possibly oblique orientation of the slit is to be understood as including any shape, curved or not, of this slit.

[0020] To ensure a functional and practical operation, it is proposed that the disc actuating means comprise a connecting rod having: - a rod passing through said discs and having a first end and a second end, and - a first joint and a second joint, respectively at the first end and the second end of the rod, the first joint being in pivot connection with the housing, the second joint being linked to a piston rod adapted to slide in a piston cylinder in pivot connection with the housing.

[0021] Thus: - We will ensure the desired group ordering of the discs is carried out safely and reliably. - except at the first joint, there will be no interference with the casing. - the casing will retain its integrity.

[0022] To facilitate ease of maintenance, replacement of all or part of the discs, or even a possible evolution in the shape that one wishes to see achieved by the slots, it is proposed that the discs of the plurality of discs be in contact with the housing, without being fixed to it, so that the discs are removable from the housing.

[0023] In particular, a peripheral support can be provided, via a radially external surface, for the discs against a radially internal surface of the housing, which then circumferentially surrounds the discs.

[0024] For comparable reasons, particularly to facilitate assembly, maintenance, and possible replacement / removal of the discs, it is also proposed: - that the housing (which surrounds the discs) comprise two housing parts joined together, and - that the discs of the plurality of discs are arranged between the two parts of the casing.

[0025] In connection with such a design of the housing in (at least) two parts, it is also preferably proposed: - either that, circumferentially around the axis of rotation, the housing comprises two housing sectors joined together, and that the discs of the plurality of discs are, around the axis of rotation, surrounded by a zone of each of said two housing sectors, - either the casing comprises axially two casing parts joined together, and the discs of the plurality of discs are arranged axially between the two casing parts.

[0026] In this way, we will continue along the modular path initiated with the disks, with the concern for ease of assembly / maintenance already expressed.

[0027] In any case, surrounding the plurality of discs with a zone (of wall) of the housing against which a circumferential support of the discs can be made will allow to combine centering and retention of the discs.

[0028] To this end, the housing may have, on its radially inner surface, a circumferential groove (in one or more parts) in which the discs will then be engaged, preferably to the bottom of the groove (radially speaking).

[0029] If they do not protrude from the groove, radially inwards (i.e. towards the axis of rotation), the discs will not require modification of the sealing conditions otherwise provided in their environment between the (heads of the) rotor blades and the housing that surrounds them.

[0030] And if the notches in the discs are formed on the radially inner circumference of these discs, the resulting slots will then be located in the groove, while also being open, radially inwardly, directly onto the relevant gas flow, thus promoting the desired (re)circulation conditions. Indeed, reinjecting gaseous fluid from downstream to upstream, up to the upstream of the relevant rotor, through the slots, makes it possible to re-energize the flow before the rotor, and thus better control the pumping.

[0031] Another consideration, consistent with the above, was also to promote the cohesion of the discs, the efficiency of the slots with respect to the gas flow to be obtained, the persistence in the search for simple and reliable solutions, with limited interference with the housing.

[0032] It is therefore proposed that the axial compressor concerned further comprise spring-effect means for axially stressing the discs, which elastically stress the discs towards each other, parallel to the axis of rotation.

[0033] In practical terms, preference may be given to a version in which the spring-effect means for axially stressing the discs will be supported between the housing and the plurality of discs and arranged to stress the discs parallel to the axis of rotation.

[0034] Also covered by this disclosure is a faired aeronautical turbomachine comprising the compressor which has just been presented, in all or part of its characteristics. Brief description of the figures

[0035] [Fig. 1] is a half-view in axial cross-section of a ducted aeronautical turbomachine to which the invention can be applied,

[0036] [Fig.2] is a view of detail II of [Fig.1],

[0037] [Fig.3] is a perspective view of a compressor rotor wheel of the tur previous bomachine surrounded by its part of the casing equipped with a TCNA with axial slots, according to a first embodiment of the invention;

[0038] [Fig.4] is a perspective view of one of the disks of the aforementioned TCNA,

[0039] [Fig.5] corresponds to detail V of [Fig.4],

[0040] [Fig.6] schematically represents, locally, a rotor wheel blade head located opposite a series of TCNA disks, while the slots are axially oriented,

[0041] [Fig.7] schematically represents, locally, a rotor wheel blade head located opposite a series of TCNA disks, while the slots are oriented obliquely,

[0042] [Fig.8] corresponds to detail VIII of [Fig.7],

[0043] [Fig.9] is an axial view of the first two TCNA disks, along arrow IX of [Fig.8], while the slots are therefore oriented obliquely,

[0044] [Fig. 10],

[0045] [Fig. 11], and

[0046] [Fig. 12] illustrate from different angles the proposed TCNA, according to a variant embodiment of the casing which surrounds the disks shown in relation to the solution illustrated [Fig.3],

[0047] [Fig. 13] illustrates precisely, to clearly show the difference, the roughly hemicylindrical half of the casing equipped with the TCNA according to the first embodiment of [Fig.3],

[0048] [Fig. 14], and

[0049] [Fig. 15], illustrate from two different angles a possible realization of the means of actuation of the disks of the proposed TCNA, allowing the said disks to be driven together around the axis of rotation. Detailed description of the disclosure

[0050] Before targeting the invention, let us present its environment, which is that of a faired aeronautical turbomachine, which can be that of [Fig.1] which illustrates an example of a known axial compression, double-flow turbojet.

[0051] The terms upstream (AM) and downstream (AV) are defined here with respect to the direction of flow of the air or gas flow F. Thus, the air or gas flow F circulating through of the turbomachine 1 is directed from upstream to downstream, that is to say from left to right in [Fig.1].

[0052] The turbomachine 1 conventionally comprises, and substantially at its upstream end, a fan 2 downstream of which extends, along the X-axis: - a primary channel 90, annular, in which a primary flow Fl flows, said primary channel passing in particular, in the direction of flow of the primary flow, through a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6 and a low-pressure turbine 7, the primary channel being delimited externally and along the X-axis by a set of fixed housings 8 (stator); and - a secondary vein referenced 9, in which flows a secondary flow distinct from the primary flow, the secondary vein 9 annularly surrounding the primary vein 90.

[0053] The secondary vein 9 is itself surrounded by a nacelle 10 forming a fairing for the turbomachine 1.

[0054] Fig.2 illustrates, at the location of reference II of Fig.1, in particular the entry zone into the primary vein 90 of said part Fl (primary air) of the air flow F.

[0055] Fig. 2 schematically represents a compressor which, like any compressor, comprises at least one compression stage, i.e. a part forming a stator followed by a part forming a rotor.

[0056] The schematic low-pressure compressor 3 comprises three successive axial compression stages E1, E2, E3, in the example. The illustration could also have schematically represented a high-pressure compressor, such as compressor 4, since what follows can also be applied to it.

[0057] Each rotor, also called a rotor wheel, comprises a circumferential row of blades 11 extending annularly around the X-axis and each radially to it. The rotor blades 11 are connected to a rotor disk (also called a hub) 15 through which they rotate around the X-axis. Each rotor blade 11 comprises a blade 12, forming the profiled portion extending in the primary duct 90.

[0058] The part forming the stator of each compression stage comprises a row of blades 17 extending annularly around the X axis and each radially to it.

[0059] A compression stage is therefore formed by a row of stator blades 17 and the row of rotor blades 11 which is axially adjacent to it, just downstream.

[0060] The blades (typically called "vanes" in English) of each row of stator blades 17 are fixed, at their radially external end 19, to a fixed external ferrule 20 belonging to the housing assembly 8 and, at their radially internal end 18, to a fixed internal ferrule 21. The external ferrules 20 and internal ferrule 21 are concentric around the X axis.

[0061] The external ferrules 20 can be defined by a series of housings 80 of the set of 8 crankcases.

[0062] The blades 11 of each row of rotor blades each have a radially internal end 13 and a free radially external end 16, called the head. Said heads 16 rotate opposite the relevant area of ​​a housing 80.

[0063] Thus, the compressor in question comprises: - at least one rotor wheel 23 adapted to rotate around the axis of rotation X, here in the 90 vein, and

[0064] - a housing 80 of the housing assembly 8 located around the rotor wheel.

[0065] At its radially internal end 13, each rotor blade 11: - either presents a foot 14 by which the blade 11 is fixed to a rotor disc, by engagement in slots of this disc distributed around its circumference, - either is monobloc with a disc, in the case of a rotor known as "DAM", monobloc bladed disc, also called "Blisk" (Bladed Disc / bladed disc) or bladed wheel.

[0066] The foregoing does not preclude the existence of a variable vane pitching system around their respective radial axes of elongation, such in particular as a variable pitching system for the stator vanes 17 known as a "Variable Stator Vane (VSV) / ​​variable pitch stator vane". In other words, regardless of how the rotor vanes 11 are connected to their rotating drive disk 15 / 15', Figures 3 and following illustrate the solution to the problem that this disclosure seeks to address.

[0067] This is illustrated from [Fig.3]: - at least a portion of the casing 80, or of the parts that equip it, and facing which the heads 16 of the rotor blades 11 must rotate, and - a TCNA crankcase treatment compressor of the "axial slots" type.

[0068] As explained, the solution of the invention will allow the slot angles to be adapted according to the operating regimes of the turbomachine, and thus to obtain gap spacings between the upstream and downstream parts of the slots adapted to the flow at the blade tip 16, depending on the operating regime of the turbomachine. Thus, these upstream / downstream angles will be chosen with respect to the flow at a specific operating point of the turbomachine.

[0069] For this purpose, a solution of the invention proposes that, on the compressor part of the aeronautical turbomachine considered, such as at the level of the compressor 3 or 4 of the turbomachine 1, the casing located around the (each) rotor wheel, casing 80 in the example, is provided internally, around the rotor wheel, such as the rotor wheel 23, with a plurality of discs, which can also be called rings, 25 with which the fluid, primary air flow Fl in this case, can come into contact.

[0070] All disks, such as 25a, 25b, of the plurality of disks 25: - are coaxial with the X axis of rotation, - are individually arranged perpendicular to the X axis of rotation, - are arranged -grouped- one after the other along the axis of rotation X, and - are mounted to rotate one another and with respect to the casing, casing 80 in the example, around the axis of rotation X.

[0071] Relative to the casing, casing 80 in the example, and the row of rotor blades which they equip, the above discs, such as 25a, 25b, of the plurality of discs 25 are arranged around the heads of the blades 11 of this row of rotor blades.

[0072] Hereinafter, reference is made to the same series of such discs. Several compression stages, or several rows of compressor rotor blades, can be equipped with the same series of discs 25.

[0073] The same plurality of disks 25, and therefore their slots 31, will be advantageously located: - around the leading edge 110, and the upstream part 111, of the blades 11 to be considered, - and even around the space 900 of the vein - primary vein 90 here - located just upstream of the said blades 11 to be considered.

[0074] Each disk, such as 25a, 25b, has a plurality of notches 27 distributed over the circumference C which it defines, around the axis of rotation X.

[0075] For ease of handling, each disc, such as 25a, 25b, will preferably be in one piece.

[0076] If the disks 25 are rotated together around the axis of rotation X by means of disk actuation means 29, the rotation of each disk, such as 25a or 25b, relative to the other disks will modify the shape of slots 31 individually created by a series of notches, such as 27a or 27b, of the plurality of notches located one after the other along the axis of rotation, such that each slot 31 can be configured as: - an axial slit, as illustrated [Fig.6], or, - an oblique slit relative to the axis of rotation X, as illustrated [Fig.7].

[0077] In other words, circumferentially around the axis of rotation X, each of the disks 25 has a succession of notches 27, each of which allows the fluid in question to pass through it. And each of these notches 27 is arranged so as to be: - aligned axially, parallel to the X-axis, with one of the notches 27 of each of the other disks of the plurality of disks 25 (as illustrated [Fig. 6]), or - angularly offset, around the X axis, relative to one of the notches of at least some of the other disks in the plurality of disks 25 (as illustrated in figures 7 to 9), so that, in all cases, the flow can pass through all the slits 31 created; see the arrows Fl on figures 6-8, 11 for the illustrated slits.

[0078] In the second case, it will be possible, in particular, to deflect the fluid flow by means of a slot 31 by a non-zero angle α such that the slot 31 in question extends, with respect to a parallel to the X-axis, along a slanted direction, considered rectilinear like that 31a [Fig. 6]. The angle α is defined between a parallel to the X-axis at the location of the slot 31 in question (see direction XI [Fig. 8] or 10), and the general direction 310 of this slot.

[0079] It could also be predicted that, from one disk 25 to another, this angle has evolved so that the slit 31 considered is arched, or has yet another shape.

[0080] Thus, it will be possible to create a non-linear, but curved, slot shape, or even one in several successive sections, each linear or non-linear.

[0081] In any event, this will solve the aforementioned problem of a lack of adaptability of the shape of non-axisymmetric arc-type crankcase treatments according to the operating regime of the turbomachine. The flow sampling zone in the fluid flow Fl and the reinjection zone can be optimized to make the crankcase treatment more efficient with respect to the flow, and thus better prevent pumping.

[0082] Around the axis of rotation X, all the slots 31 of the casing treatment can present, at the same time, the same angle a.

[0083] The angle a can typically be between -30° and 30° with respect to the X axis, thus covering the two possible directions of rotation of a rotor around the X axis.

[0084] The invention allows the shape of the slots 31 to be adapted over the entire circumference. The upstream and downstream angles of the slots can be controlled independently by means of the disks.

[0085] The rotation of each disc, considered relative to the others, allows the shape of the slots 31 in the housing treatment to be modified. And the overall alignment of these slots 31 is modified by the displacement – ​​the rotation in the azimuthal direction – of the entire set of discs 25.

[0086] Let us consider that, in a plane P2 perpendicular to the X axis, we reference [3 (see [Fig.9]) the angle of deviation, on any one of the disks 25, between: - a reference frame 29 where the notch in question belongs to a straight and axial slot 31, and - the angular position of this notch necessary to obtain an orientation of this slot, and therefore a priori of all the slots, 31 at an angle with respect to a parallel to the X axis, as mentioned above.

[0087] On [Fig.9], the corresponding angle [3] marks azimutally the angular variation between a notch 27a of the first disk 25a and the notch 27b of the second disk 25b located just behind it, assuming that we wish to obtain a slot 31 oblique with respect to the X axis, as on [Fig.7].

[0088] To obtain an angle a such that the slit 31 taken into account is straight, at an angle, with respect to a parallel to the axis X, this angle [3 will therefore be continuously increasing from the first disk 25a of the plurality of disks - encountered by the flow flowing from upstream to downstream - to the last disk, marked 25f [Fig.7].

[0089] Each notch can be formed in the radially inner circumference of the disc 25 considered, which will give the disc a shape with a crenellated inner circumference and will promote the effect caused on the flow Fl by the passage of the rotor blades.

[0090] It will be possible to foresee: - between three and one hundred 25-disc discs (for example, 10 discs as in the illustrations); and - between eight and more than fifty notches on the circumference of each disc 25. An equidistant distribution can be provided; with therefore as many slots for the discs considered together.

[0091] Increasing the number of discs will reduce the step between two successive disc notches / slots, which will improve the surface condition of the slots and therefore the aerodynamic behavior of the housing treatment.

[0092] A limit to the number of notches, or even to the number of discs, may be the creation of "steps" between successive slotted discs: the resulting crenellated effect deteriorates aerodynamic efficiency.

[0093] Each in a plane (such as plane P2) perpendicular to the X axis and arranged axially adjacent to each other, the disks 25 will slide along each other around the X axis.

[0094] These disks 25 will preferably each have lateral surfaces, - axially opposed - 250a, 250b, flat, this therefore at the place of their interfaces.

[0095] On the radially inner surface 253, and opposite the considered row of rotor blades 11, the housing has a circumferential groove 35.

[0096] The (each) groove 35 is adapted to receive all the axially adjacent discs 25 of the same series of discs 25.

[0097] When correctly engaged in the groove 35, the discs 25 may just be flush with the edges and surfaces, respectively upstream 255a and downstream 255b of the groove 35, which thus define a portion of said radially internal surface 253 of the housing. Therefore, the general profile defined by the radially internal surface 253 will not be disrupted by the discs 25.

[0098] If each notch 27 is formed in a radially internal circumference of the disk 25 considered, the slots 31 will then be located in the groove 35, while being open, in a radially internal manner, directly onto the flow Fl as schematically shown by way of example [Fig. 11].

[0099] To stress the disks towards each other parallel to the axis of rotation X, the compressor may further include means 33 which elastically stress the discs 25 towards each other.

[0100] In particular, spring-effect means 33 can be provided which press on the discs to hold them.

[0101] In order to participate in the common rotational movement of the discs 25 around the axis X, the spring-effect means 33 for axially stressing the discs can be axially active, supported between the housing, housing 80 in the example, and the first or last disc of the plurality of discs 25, so as to be arranged to stress the discs parallel to the axis of rotation X.

[0102] For the same plurality, or series, of discs 25, the spring-effect means 33 will then be located in the same groove 35, being circumferentially distributed there.

[0103] As for the discs 25 themselves, it may be useful to connect them physically to the housing, housing 80 in the example, only by pressing against the housing, without them being fixed to the housing, so that the discs 25 can rotate, or even be removable from the housing.

[0104] The discs 25 will be usefully centered on the axis of rotation X due to the outer diameters of the discs 25 which are only slightly less than the inner diameter of the housing.

[0105] In particular, a minimal radial clearance j ([Fig. 11]) may be provided for this purpose, consisting of a non-blocking peripheral quasi-support of the radially external surface 251 of the discs, defined by the set of circumferences of the discs, against a radially internal surface 253 of the housing then circumferentially surrounding the discs.

[0106] Around the discs 25, the radially inner surface 253 of the housing will thus itself be advantageously located radially: - around the leading edge 110, and the upstream part 111, of the blades 11 to be considered, - and even around the space 900 of the vein - primary vein 90 here - located just upstream of the said blades 11 to be considered.

[0107] As explained earlier in this text, one might wish: - that the crankcase, crankcase 80 in the example, comprises two crankcase parts 80a, 80b joined together, and - that the discs of the plurality of discs 25 are arranged between the two parts 80a,80b of the casing.

[0108] Two possible configurations, of which figures 10-12 on the one hand and 3,13 on the other hand are possible schematic illustrations respectively.

[0109] In the first configuration: - the housing axially comprises said two housing parts 80a, 80b joined together, and - the disks of the plurality of disks 25 are arranged axially between the two crankcase parts.

[0110] Said two parts 80a,80b thus form the upstream and downstream parts of the casing respectively.

[0111] The disks of the plurality of disks 25 are, around the axis of rotation X, surrounded by a circumferential zone, 820a in the example, of the upstream part 80a of the housing.

[0112] A surface of this area defines the bottom 35a of the circumferential groove 35.

[0113] The circumferential zone 820a belongs to a circumferential projection 800a downstream which is present in the upstream part 80a of the casing and which is axially engaged in an axial step 800b downstream which is present in the downstream part 80b of the casing; the reverse being also possible.

[0114] The groove 35 is thus axially defined between two radial walls, respectively of the upstream part 80a and the downstream part 80b of the housing.

[0115] In this way, after engaging the discs 25 axially, one after the other, in the groove part 35 formed by the part of the housing provided with said projection, it will suffice to bring the second part of the housing axially closer to them, until it stops between the projection and the notch.

[0116] In the second configuration: - circumferentially around the axis of rotation X, the housing, housing 80 in the example, comprises at least two housing sectors: two semicircular sectors in section in the example, 810a, 810b, joined together and forming respectively the two aforementioned parts of the housing, and - the disks of the plurality of disks 25 are, around the axis of rotation X, surrounded by a circumferential zone, respectively 822a,822b in the example, of said housing sectors.

[0117] Each sector of the housing will present the corresponding sector of the groove 35, the bottom of which will be formed by the combined circumferential zones 822a,822b.

[0118] In this way, after bringing the discs 25 together axially, one after the other, it will suffice to engage them for example in the sector 810a of the housing, then to arrange the sector 810b around them, until the radial meeting of the housing sectors.

[0119] Thus joined together, the housing sectors will be fixed radially to each other by any means, for example screwing; same for the first configuration in which the joining is axial.

[0120] Arranged as they are, the discs of the plurality of discs, 25, must be ordered so that the slots 31 can achieve the desired shape.

[0121] To this end, the compressor 3,4 concerned is therefore provided with means 37 for actuating the discs, adapted to drive said discs together around the axis of rotation X; see figures 14, 15, if necessary to be associated with figures 5-11 to visually observe the following.

[0122] The rotation of at least one disk, such as 25a, relative to the other disks, such in particular as 25b or 25f, of the plurality of disks, induced by the disk actuation means 37, makes it possible to modify the shape of the slots 31 individually created by each series of notches 27 located, one after the other, along the axis of rotation, such that each slot 31 can therefore, as already mentioned, be presented in the following manner: - of an axial slit, or - of a slit oriented obliquely (angle a) with respect to the axis of rotation X, in a first plane (PI [Fig.8]): — passing through the slot (see section plane IX-IX [Fig. 11]), and — perpendicular to a second plane (see section plane XX [Fig. 11], or plane P2 figures 8,9) radial to the axis of rotation X, which axis X is therefore parallel to the first plane PI.

[0123] The discs 25 and the means 37 for actuation of these discs are adapted to favorably drive these discs around the axis of rotation X: - all in common following said oblique orientation, and - this according to an angle (angle a) with respect to a parallel to the axis of rotation which is all the more important as we consider the said disks from the first (25a) to the last (25f); this being also true for the angle [3 with respect to the reference position 29).

[0124] To be operational, the means 37 for actuation of the discs 25 may include a connecting rod 39 having: - a rod 41, and - a first joint 43a and a second joint 43b. The first joint 43a is connected to the housing 80 via a pivot joint. The second joint is connected to a rod 45a of a piston 45 adapted to slide within a cylinder 45b of the piston. The cylinder 45b of the piston is connected to the housing 80 via a pivot joint.

[0125] The connecting rod 41 passes through the discs, from the first (25a) to the last (25f), through a common passage 47 provided through each disc in the series.

[0126] On either side of the series of discs 25, the first joint of the connecting rod 39 is located at one end of the rod 41 and the second joint 43b at the second end.

[0127] Thus, the second joint 43b connects the rod 41 of the connecting rod 39 and the rod 45a of the piston.

[0128] Figures 14 and 15, reference 49 schematically represents the shaft through which the cylinder 45b of the piston is in pivot connection with the housing 80.

Claims

Demands

1. Axial compressor of an aeronautical turbomachine comprising: - at least one rotor wheel (11) adapted to rotate about an axis of rotation (X) of the compressor, in a channel (90) where a fluid can flow, - a housing (8,80) located around the rotor wheel, characterized in that: - the casing is provided internally, around the rotor wheel, with a plurality of discs (25) with which the fluid can come into contact and which: — are coaxial with the axis of rotation, — are arranged individually perpendicular to the axis of rotation, — are arranged one after the other along the axis of rotation, — are mounted to rotate relative to each other and relative to the housing (8,80), around the axis of rotation, each disc of the plurality of discs (25) defining a circumference around the axis of rotation, and having a plurality of notches (27) distributed over the circumference, and - the axial compressor (3,4) further includes means (37) for actuating the discs, adapted to drive said discs together around the axis of rotation, the induced rotation of at least one disc relative to the other discs of the plurality of discs allowing the shape of slots (31) individually created by a series of notches of the plurality of notches (27) located one after the other along the axis of rotation to be modified, such that each slot can be in the following configuration: - an axial slit, or - a slit oriented obliquely (a) with respect to the axis of rotation (X), in a plane (PI): — passing through the slit (31) and — parallel to the axis of rotation (X).

2. Compressor according to claim 1, wherein the discs of the plurality of discs (25) are arranged successively, along the axis of rotation (X), from a first disc to a last disc, and the discs and the means (37) for actuation of the discs are adapted to drive, in said oblique orientation, all in common, said disks around the axis of rotation, at an angle (a) which is all the more important as we consider the said disks (25), from the first to the last.

3. Compressor according to claim 1 or 2, wherein the means (37) for actuating the discs comprise a connecting rod (39) having: - a rod (41) passing through said discs and having a first end and a second end, and - a first articulation (43a) and a second articulation (43b), respectively at the first end and the second end of the rod, the first articulation being in pivot connection with the housing (8,80), the second articulation being linked to a piston rod (45a) adapted to slide in a piston cylinder (45b) in pivot connection with the housing.

4. Compressor according to any one of the preceding claims, wherein the discs of the plurality of discs (25) are supported against the casing, without being fixed to it, so that they are removable from the casing (8,80).

5. Compressor (12) according to any one of the preceding claims, in which the casing (8,80) has a groove (35) in which the discs (25) are engaged without radially protruding from it.

6. Compressor according to any one of the preceding claims, wherein: - the housing comprises two housing parts (80a,80b; 810a, 810b) joined together, and - the discs of the plurality of discs (25) are arranged between the two housing parts.

7. Compressor according to any one of claims 1 to 5, wherein: - the casing axially comprises two casing parts (80a, 80b) joined together, and - the discs of the plurality of discs (25) are arranged axially between the two casing parts.

8. Compressor according to any one of claims 1 to 5, wherein: - circumferentially around the axis of rotation (X), the housing comprises two housing sectors (810a, 810b) joined together, and - the discs of the plurality of discs (25) are, around the axis of rotation, surrounded by an area (822a,822b) of each of said two housing sectors.

9. Compressor according to any one of the preceding claims, further comprising spring-effect means (33) for axially loading the disks, which elastically stress the disks (25) towards each other parallel to the axis of rotation (X).

10. Compressor according to claim 9, wherein the spring-effect means (33) for axially stressing the discs are supported between the casing (80) and the plurality of discs (25) and arranged to stress the discs parallel to the axis of rotation.

11. Aeronautical turbomachine (1) comprising the compressor (12) according to any one of the preceding claims.