PARTICULATE TRAP FOR AIRCRAFT TURBOMACHINE COMPRISING A TWO-PART DUCT

Abstract

The invention relates to a particle trap (28) for an aircraft turbomachine (20), comprising a housing (32) connected to an air inlet of the turbomachine, a first duct connected to said housing, a plurality of injectors (36) mounted in the first duct (34) and capable of being supplied with pressurized air, and a second duct engaged in the first duct and having a constriction, characterized in that the second duct (40) comprises, from upstream to downstream, separable first and second parts (56, 58). Figure 6 for the abstract.

Description

Title of the invention: PARTICLE TRAP FOR AN AIRCRAFT TURBO-MACHINE COMPRISING A DUCT IN TWO PARTS Technical field of the invention

[0001] The invention relates to a particle trap for an aircraft turbomachine, in particular a helicopter, a turbomachine comprising such a particle trap, an aircraft comprising such a turbomachine, and a method for mounting or dismounting this turbomachine in the aircraft. Technical background

[0002] It is known to drive a main air flow by means of a secondary air flow that is more energetic than the main air flow to enable the ejection of particles captured in a particle trap. A device for driving a main air flow of this type conventionally comprises a flow duct for a main air flow and ejectors for a secondary air flow located inside the duct and configured to eject the secondary air flow that will force the flow of the main air flow by viscous entrainment in this duct.

[0003] Ejectors, also called jet pumps, are supplied with high pressure and / or high temperature air. The difference in momentum between the two flows generates a viscous entrainment of the lower pressure main air flow and therefore its suction into the pipe. The following prior art documents describe several applications of this type of device: WO-A1-2014 / 060656, FR-A1-3 011 583, FR-A1-3 022 588 and FR-A1-3 087 239.

[0004] One of the problems with this type of device concerns the control of turbulence and pressure losses at the outlet of the ejectors, which reduce the performance of the device and may require it to be oversized for a given application. This then affects the pressure balance between the upstream of the primary flow, the secondary flow and the downstream of the system exhaust.

[0005] When the pressure upstream of the device decreases and / or the pressure losses and turbulence are too great at the outlet of the ejectors, the generated Venturi effect loses its effectiveness. At a certain threshold of pressure losses upstream of the system generated by the intake device, the main air flow reverses and the secondary air flow is sucked back upstream, which can damage the parts in this area.

[0006] This problem is particularly penalizing in the case of drive devices intended to equip a particle trap in an aircraft turbomachine.

[0007] Indeed, such a particle trap generally comprises at least one enclosure connected to an air inlet of the turbomachine making it possible to decant the air coming from the air inlet and at least one conduit which is connected to this enclosure and which extends parallel to the axial direction of the turbomachine.

[0008] At the outlet of the turbomachine, at least one duct of this particle trap opens into an extraction duct which is aligned with a free end of the duct and which passes through a firewall of the aircraft located downstream of the turbomachine.

[0009] Given the limited space requirement of the engine compartment, it was not considered to oversize the air flow drive device to overcome the aforementioned drawbacks.

[0010] A preferred solution to avoid reaspiration phenomena consists of using a conduit comprising a constriction downstream of the injectors.

[0011] Such a duct comprises, in a known manner, a first axial duct which is connected to the enclosure and which has a first passage section, a plurality of injectors mounted in the first duct and capable of being supplied with pressurized air, and a second duct which opens opposite the extraction duct.

[0012] This second conduit has an upstream end which is engaged in a sealed manner in the first conduit downstream of said injectors and it has a constriction.

[0013] Indeed, the second conduit comprises, from upstream to downstream, a first axial section which has a passage section decreasing from the first passage section to a second passage section, then a second axial section continuously having the second passage section, and finally a third axial section which has an increasing passage section from the second passage section to a third passage section. The third passage section is equal to or greater than the first passage section.

[0014] Conventionally, the second conduit is inserted into the first conduit so that it penetrates therein along at least a portion of the first section. As a result, the second conduit projects out of the first conduit.

[0015] In order for the second duct to efficiently discharge the particle-laden air into the extraction duct, it must be arranged at a specific reduced distance upstream of this duct.

[0016] However, the aircraft comprises upstream of the turbomachine a power transmission device which is coupled to the turbomachine. Depending on the configurations, a shaft of the power transmission device enters the turbomachine, or conversely, a shaft of the turbomachine enters the power transmission device. The uncoupling of the turbomachine from the power transmission device to extract this shaft involves in any case a recoil of the turbomachine along a stroke which is greater than the determined distance.

[0017] In this configuration it is therefore not possible to dismantle the turbomachine without first removing the entire particle trap or the firewall, when this is possible.

[0018] There is therefore a need for a second duct that can be dismantled to allow the axial recoil of the turbomachine and without requiring the complete removal of the particle trap, this second duct having to be able to be manufactured in a simple manner. Summary of the invention

[0019] The invention aims to remedy this drawback by proposing a particle trap whose second conduit can be dismantled in sections, in order to allow its extraction prior to retraction and dismantling of the turbomachine.

[0020] For this purpose, the invention proposes a particle trap for an aircraft turbomachine, said particle trap comprising:

[0021] - an enclosure configured to be connected to an air inlet of said turbomachine,

[0022] - a first conduit of axis B which is connected to said enclosure and which has a first section of passage,

[0023] - a plurality of injectors mounted in the first conduit and capable of being supplied with pressurized air, and

[0024] - a second conduit of axis B, one upstream end of which is engaged in a sealed manner in the first conduit downstream of said injectors, said second conduit comprising from upstream to downstream: • a first axial section which has a passage section decreasing from the first passage section to a second passage section, • a second axial section continuously presenting the second passage section, and • a third axial section which has a passage section increasing from the second passage section to a third passage section,

[0025] characterized in that the second conduit comprises from upstream to downstream first and second parts which are separable at one end of the second section.

[0026] The splitting of the second duct into two parts advantageously makes it possible to extract the second downstream part from the engine compartment, thus allowing the turbomachine to be uncoupled from the power transmission device, then moved back and finally extracted from the engine compartment.

[0027] According to other characteristics of the particle trap:

[0028] -the first part comprises the first section and the second part comprises the second and third sections, the two parts being separable at the junction of the first and second sections.

[0029] - the first and second parts each respectively comprise at least one first flange and a second flange which extend transversely relative to the axis B, and said first and second flanges being of the same transverse size and being clamped against each other by a collar having at least one concave axial section which covers at least edges of said first and second flanges,

[0030] - the first flange has a transverse dimension which is greater than the first passage section, said first flange being able to be received axially in abutment against a downstream end of the first conduit,

[0031] - the first conduit carries a third flange set back from its downstream end extending transversely with respect to the axial direction A, and in that the first, second and third flanges of the same transverse size and clamped together by the collar,

[0032] In the particle trap according to the invention:

[0033] - the first and second flanges are shaped in the form of first and second collars which extend transversely relative to the axis B and whose contact faces are arranged against each other,

[0034] - each of the first and second collars comprises the two edges which are transversely opposed and in an arc of a circle and, on a face opposite its contact face, first and second associated beads, transversely opposed and in an arc of a circle, which fit said edges,

[0035] - the third flange has two third arc-shaped beads, transvers dirty opposites, which are arranged in contact with the first ridges, and

[0036] - the collar comprises at least two transversely arcuate sections opposite, which cover the first to third beads and keep them tight against each other, and which are kept tight by cladding,

[0037] - the first and third beads are tubular and each have a section open towards axis B, each bead comprising an annular wall transverse to axis B resting on a transverse annular wall of the other bead,

[0038] - the transverse annular wall of the first bead has an internal end shaped into a pad configured to guide said first bead on the downstream end of the first conduit,

[0039] - an upstream end of the pad is curved away from the axis B according to a collar facilitating the introduction of the first bead on the downstream end of the first conduit,

[0040] - the first flange comprises an annular elastic seal which is carried by the face of the first flange opposite its contact face and which is interposed between the first collar of the first flange and the downstream end of the first conduit,

[0041] - the cladding comprises at least two strips enclosing the two sections of the collar, which are connected at their free ends by tie rods of adjustable length,

[0042] - each conduit has an oblong cross-section extending along an axis Main elongation T with two opposite semi-cylindrical walls along said main axis T,

[0043] The invention also relates to an aircraft turbomachine extending substantially in an axial direction A and comprising at least one air inlet, characterized in that it comprises a particle trap of the type described above, the first and second ducts of this particle trap extending in the axial direction B parallel to the axial direction A, and laterally along the turbomachine.

[0044] The invention also relates to an aircraft comprising a power unit comprising:

[0045] - a turbomachine of the type described above,

[0046] - a power transmission device placed upstream of the turbomachine and coupled to said turbomachine, and

[0047] - an engine compartment comprising a firewall, which is arranged downstream of the turbomachine and which comprises a convergent extraction duct which is aligned with a free end of the second duct and which has an inlet section greater than the third passage section of the third section of the second duct.

[0048] The invention finally relates to a method for extracting a turbomachine from an aircraft as described above, said turbomachine being coupled to the power transmission device by means of a shaft capable of being extracted along a determined stroke, and the free end of the second duct being arranged at a determined distance from the extraction duct which is less than said determined stroke, characterized in that it comprises the following steps:

[0049] a) decoupling the turbomachine from the power transmission device,

[0050] b) separating the turbomachine from the power transmission device by moving the turbomachine back in the axial direction A by a distance greater than the determined stroke until the second part of the second duct enters the extraction duct and comes into abutment there,

[0051] c) separating the first and second parts of the second conduit,

[0052] d) extracting the turbomachine from the engine compartment substantially transversely relative to the axial direction A, the second part of the second duct remaining in the extraction duct.

[0053] The invention finally relates to a method for mounting / remounting a turbomachine of an aircraft as described above, said turbomachine being able to be coupled to the power transmission device by means of a shaft able to be introduced according to a determined stroke, and the free end of the second duct being able to be arranged at a determined distance from the extraction duct which is less to said determined stroke, characterized in that it comprises the following steps:

[0054] A) placing the second part of the second duct in the extraction duct,

[0055] B) inserting the turbomachine into the engine compartment substantially transversely with respect to the axial direction A, aligning the second part of the second duct with the first part of the second duct,

[0056] C) fixing the second part of the second duct to the first part of the second duct,

[0057] D) aligning the turbomachine with the power transmission device,

[0058] E) moving the turbomachine towards the power transmission device in the axial direction A by a distance corresponding to the determined stroke,

[0059] F) coupling the turbomachine with the power transmission device. Brief description of the figures

[0060] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0061] [Fig.l] [Fig.l] is a schematic view illustrating the positioning of a turbomachine having a particle trap with a second single-piece duct according to the state of the art in an aircraft engine compartment;

[0062] [Fig.2] [Fig.2] is a schematic view illustrating the impossibility of recoil and de turbomachine compartment having a particle trap with a second single-piece duct in the engine compartment;

[0063] [Fig.3] [Fig.3] is a schematic view illustrating the impossibility of recoil and de engagement of the second conduit of the particle trap in the previous configuration;

[0064] [Fig.4] [Fig.4] in a schematic view illustrating a second single-piece conduit received in a first conduit of a particle trap;

[0065] [Fig.5] [Fig.5] is a schematic view illustrating the positioning of a tur bomachine having a particle trap with a second two-part duct in an aircraft engine compartment;

[0066] [Fig.6] [Fig.6] is a schematic view illustrating the possibility of recoil and de engagement of a second part of a second two-part conduit of a particle trap according to the invention;

[0067] [Fig.7] [Fig.7] is a schematic view illustrating the recoil and clearance of the turbomachine having a particle trap with a second two-part duct according to the invention outside the engine compartment;

[0068] [Fig.8] [Fig.8] is an exploded perspective view of the first duct, the two parts of the second duct, and the turbomachine;

[0069] [Fig.9] [Fig.9] is an assembled perspective view of the first conduit, the two parts of the second duct, and of the turbomachine;

[0070] [Fig. 10] [Fig. 10] is an assembled sectional view of the first duct, the two parts of the second duct, and the turbomachine;

[0071] [Fig. 11] [Fig. 11] is a detail view of [Fig. 11];

[0072] [Fig. 12] [Fig. 12] is a perspective view of the first part of the second conduit;

[0073] [Fig. 13] [Fig. 13] is a perspective view of the first part of the second conduit assembled to the first conduit;

[0074] [Fig. 14] [Fig. 14] is another perspective view of the first part of the second conduit assembled to the first conduit;

[0075] [Fig. 15] [Fig. 15] is a perspective view of the second part of the second conduit;

[0076] [Fig. 16] [Fig. 16] is a perspective view of the first conduit, and of the two parts of the second conduit assembled together;

[0077] [Fig. 17] [Fig. 17] is a block diagram illustrating the steps of extracting a turbomachine from an aircraft;

[0078] [Fig. 18] [Fig. 18] is a block diagram illustrating the steps involved in removing a turbomachine from an aircraft. Detailed description of the invention

[0079] Figures 1 to 3 show an aircraft power unit 10, housed in an engine compartment 12 of the aircraft.

[0080] In a known manner, the power unit 10 is housed between two upstream 14 and downstream 16 firewalls of the engine compartment 12. It comprises from upstream to downstream a power transmission device 18, and a turbomachine 20 of axis A which is coupled to this power transmission device 18. The power transmission device 18 is a device specific to the aircraft in which the power unit 10 is placed. It may be a reducer driving a propeller in the case of an airplane turboprop or a reducer coupled to a transmission linked to a main rotor and to a tail rotor in the case of a helicopter, without limitation of the invention.

[0081] The turbomachine comprises very schematically a compressor assembly 22, a combustion chamber 23 and a turbine assembly 24, which drive at least one drive shaft 26 which is coupled to the power transmission device 18. The drive shaft 26 enters the power transmission device 18 to ensure its drive. It will be understood that this arrangement is not limiting of the invention and that conversely a shaft of the power transmission device 18 could enter the turbomachine 20 to ensure the coupling. For its ac coupling, the motor shaft 26 must be introduced according to a determined stroke L, visible in figures 1 and 3. For its uncoupling, the turbomachine 20 must therefore be moved back by at least the determined stroke L.

[0082] The turbomachine also comprises a particle trap 28 which is capable of capturing particles before they enter its compressor assembly 12, and which extends laterally along the turbomachine.

[0083] The turbomachine 20 comprises, upstream of its compressor assembly 22, an air inlet 30 through which the air is admitted into the compressor assembly 22.

[0084] The air inlet 30 comprises from upstream to downstream a divergent section 30a, followed by a convergent section 30b, which are designed so that the particles are entrained substantially at the junction of these two sections. The particle trap 28 comprises an enclosure 32 which is configured to be connected to the air inlet 30 at the junction of these two sections 30a, 30b and which can thus receive almost all of the particles entering the air inlet 30 of said turbomachine. Downstream of the enclosure 32, the particle trap comprises a first duct 34 extending generally in a direction of axis B parallel to the axial direction A. This first duct 34 is connected to the enclosure 32 and it has a first passage section SI, as shown in [Fig. 4],

[0085] A plurality of injectors 36 are mounted in this first conduit 34 near its outlet and they are capable of being supplied with pressurized air by an air box 38, supplied with pressurized air, which traps a portion of the first conduit 34.

[0086] The particle trap comprises a second conduit 40, also of axis B, one upstream end 42 of which is engaged in a sealed manner in the first conduit 34 downstream of the injectors 36. The second conduit is engaged in the first conduit 34 at a distance L'.

[0087] The second conduit 40 is provided to avoid re-aspiration phenomena in the first conduit 34. To this end, as illustrated in [Fig.4], the second conduit 40 comprises a constriction 44 downstream of the injectors 36.

[0088] More particularly, as illustrated in [Fig.4], the second conduit 40 comprises, from upstream to downstream: • a first axial section 46 which has a passage section decreasing from the first passage section SI to a second passage section S2, • a second axial section 48 forming the constriction 44 and continuously presenting the second passage section S2, and • a third axial section 50 which has a passage section increasing from the second passage section S2 to a third passage section S3.

[0089] As shown in Figures 1 to 3, the engine compartment 12 comprises a convergent extraction duct 52 which passes through the firewall 16 and which is aligned with a free end 54 of the second duct 40. As illustrated in [Fig.l], this duct 52 is shaped as a convergent having an inlet section S4 greater than the third section S3 of the third section 50 and an outlet section S5 less than the third section S3 of the third section 50.

[0090] For the sake of compactness, the firewall 16 and the duct 52 are generally very close to the turbomachine 20. Therefore, as illustrated in [Fig. 1], the free end 54 of the second duct 40 is, in the mounted position of the turbomachine 20, arranged at a determined distance 1 from the inlet of the extraction duct 52 which is less than the determined stroke L for mounting the shaft 26, and also less than the distance L' of engagement of the second duct 40 in the first duct 34, as illustrated in FIGS. 1 and 2.

[0091] This configuration poses several problems.

[0092] Indeed, as illustrated in [Fig. 2], the second duct 40 being mounted in the first duct, as soon as the turbomachine 20 is moved back along the stroke L to allow the latter to be uncoupled from the power transmission device 18, as shown in [Fig. 2], the second duct 40 enters the extraction duct, thus making it impossible to extract the turbomachine 20 from the engine compartment 10 transversely relative to the axial direction A.

[0093] Indeed, the distance 1 determined between the downstream end 54 of the second conduit and the extraction conduit 52 is less than the stroke L.

[0094] Similarly, as illustrated in [Fig. 3], the proximity of the second conduit 40 to the extraction conduit 52 prevents its disassembly from the first conduit 34, because the latter is engaged in the first conduit 34 at a distance L' which is greater than the distance d. The recoil of the second conduit 40 causes it to penetrate into the extraction conduit 52 and thus prevents its extraction.

[0095] In this configuration, the dismantling of the second duct 40 or of the turbomachine 20 therefore requires the prior dismantling of the firewall 16, when this is possible, or at least the removal of the entire particle trap 28.

[0096] The invention proposes to remedy these drawbacks by proposing a second conduit 40 separable into at least two parts 56, 58.

[0097] The separation of the second duct 40 into two parts 56, 58 advantageously makes it possible to uncouple the turbomachine 20 from the power transmission device 18 and then to move it back until the second part of the second duct 40 enters the extraction duct 52, then to separate the first and second parts 56, 58 of the second duct 40 as shown in [Fig. 6], then to extract the turbomachine 20 transversely with respect to the axial direction A as shown in [Fig. 7], the second part 58 of the second duct remaining in the extraction duct 52, from where it can possibly be extracted after extraction of the turbomachine 20.

[0098] For manufacturing reasons, each of the sections 46, 48, and 50 being manufactured independently before its assembly with the other sections, it is desirable that the separation plane of the second conduit intervenes between the first and second sections 46, 48 or between the second and third sections 48, 50.

[0099] For this purpose, as shown in Figures 5 to 16, the second conduit 40 comprises from upstream to downstream at least first and second parts 56, 58 which are separable at one end of the second section 48.

[0100] As illustrated in Figures 8 and 11 to 15, the first part 56 comprises the first section 46 and the second part 58 comprises the second and third sections 48, 50. The two parts 56, 58 are therefore separable at the junction of the first and second sections 46, 48, that is to say at the upstream end of the second section 48.

[0101] The second and third sections 48, 50 are for example assembled together by welding or brazing.

[0102] As illustrated in Figures 8 and 11 to 15, the first and second parts 56, 58 each respectively comprise at least one first flange 60 and one second flange 62 which extend transversely relative to the axis B. These two flanges have the same transverse size S6; they are clamped against each other by a collar 64 which has at least one concave axial section and which covers at least one of these first and second flanges 60, 62.

[0103] The first flange 62 has a transverse size S6 which is greater than the first passage section SL. Therefore, when the first part 46 is inserted into the first conduit 34, the first flange 60 is received axially in abutment against a downstream end 66 of the first conduit 34, which thus makes it possible to define the axial position of the second conduit 40.

[0104] Advantageously, the collar 64 is not limited to ensuring the fixing of the first and second parts 56, 58 of the second conduit 40 but it also makes it possible to ensure the fixing of the second conduit 40 to the first conduit 34. For this purpose, the first conduit 34 carries, set back from its downstream end 66, a third flange 68 which extends transversely relative to the axis B and which is also trapped by the collar 64. The third flange 68 is for example welded to the first conduit 34.

[0105] The first, second and third flanges 60, 62, 68 have the same radial size S6 and are clamped together by the collar 64. The concave section of the collar 64 is shaped with a truncated groove profile 70 which encloses the three flanges 60, 62, 68.

[0106] Generally, as can be seen in Figures 12 to 15, the first and second flanges 60, 62 are shaped in the form of first and second necks strips which extend around the sections 46, 48 of the second conduit 40, transversely relative to the axis B and of which respective contact faces 70, 72 are arranged against each other.

[0107] The shape of the flanges 60, 62, 68 is not necessarily circular.

[0108] Indeed, as illustrated in [Fig. 16], in the embodiment shown here, each conduit 34, 40 has an oblong cross-section extending along a main axis of elongation T with two opposite semi-cylindrical walls along said main axis T.

[0109] It is therefore not necessary to assemble the flanges 60, 62, 68 together along their entire periphery. Also, as illustrated in FIGS. 11, 12 and 15, each of the first and second collars 60, 62 has two transversely opposite edges 74, 76 in an arc of a circle and, on a face opposite its contact face, first and second associated beads 78, 80 which are transversely opposite and have an arc of a circle shape, and which fit these edges 74, 76.

[0110] As illustrated in Figures 8 and 11, the third flange 68 also comprises two third beads 82 in an arc of a circle, transversely opposed, which are arranged in contact with the first beads 78.

[0111] As can be seen in [Fig. 11], the first and third beads 78, 82 are tubular and each have a section open towards the axis B, each bead 78, 82 comprising an annular wall 84, 86 transverse to the axis B and which bears on a transverse annular wall 86, 84 of the other bead. These walls 84, 86 make it possible to provide an elastic character to the beads 78, 82, which makes it possible to obtain a play-free assembly of the beads 78, 82 when they are tightened by the collar 64.

[0112] Advantageously, as illustrated in [Fig. 1 1], to promote the guiding of the first part 56 during its introduction into the first conduit 34, the transverse annular wall 84 of the first bead 78 comprises an internal end 92 which is shaped into a pad configured to guide the first bead 78 on the downstream end 66 of the first conduit 34.

[0113] The pad has a curved edge 94 which is turned axially towards the first conduit 34 and curved away from the axis B. This edge forms a chamfer 94 facilitating the introduction of the end 92 shaped as a pad.

[0114] Once the assembly of the flanges 60, 62, 68 has been carried out, the first flange 60 bears both on the third flange 68 and on the downstream end of the first conduit 34. This includes a risk of hyperstatic assembly resulting in a contact defect on one or other of these supports. To prevent such an assembly defect from occurring, the first flange 60 is mounted elastically relative to the end 66 of the first conduit 34.

[0115] Thus, the first flange 60 comprises an annular elastic seal 96 which is carried by the face 98 of the first flange 60 opposite the contact face 70 and which is interposed between the first collar 60 of the first flange and the downstream end 66 of the first conduit 34.

[0116] In the same way that the beads 78, 80, 82 do not extend along the entire circumference of the flanges, the collar 64 only comprises sections of concave sections which only trap the beads 78, 80, 82. Thus, the collar 64 comprises at least two transversely opposed arc-shaped sections 88, which cover the first to third beads 78, 80, 82, as shown in particular in FIGS. 11 and 16, and keep them tight against each other. These sections 88 are connected to each other.

[0117] These two sections 88 could be connected to each other in different ways. In the preferred embodiment of the invention, as shown in [Fig. 16], the sections 88 are surrounded and held tightly against each other by a cladding 90.

[0118] As illustrated in [Fig. 16], the cladding 90 comprises at least two strips 100 enclosing the two sections 88 of the collar, which are connected at their free ends by tie rods 102 of adjustable length. The tie rods 102 comprise, for example, screw-nut systems.

[0119] In this configuration, as illustrated in [Fig.17], such a second conduit 40 in two parts 56, 58 allows easy disassembly of the turbomachine 20.

[0120] Thus, the turbomachine 20 can be extracted according to a method comprising a first step a) during which the turbomachine 20 is decoupled from the power transmission device 18.

[0121] Then during a step b), shown in [Fig.6], the turbomachine 20 is separated from the power transmission device 18 by moving the turbomachine 20 back in the axial direction A by a distance greater than the determined stroke L until the second part 58 of the second duct 40 enters the extraction duct 52 and comes into abutment there.

[0122] Then during a step c) also shown in [Fig.6]; the first and second parts 56, 58 are separated from the second conduit 40 by removing the collar 64.

[0123] It is then possible, as shown in [Fig.7], during a step d), to extract the turbomachine 20 from the engine compartment 12 substantially transversely relative to the axial direction A, the second part 58 of the second duct 40 remaining in the extraction duct 52. This can be extracted subsequently if necessary.

[0124] Conversely, a method of mounting or reassembling the turbomachine comprises a first step A) during which the second part 58 of the second duct 40 is placed in the extraction duct 52, according to the configuration of [Fig.7],

[0125] Then during a step B) the turbomachine 20 is inserted into the engine compartment 12 substantially transversely with respect to the axial direction A, in aligning the second part 58 of the second conduit 40 with the first part 56 of the second conduit, as shown in [Fig.6]. The second part 58 of the second conduit 40 is then fixed during a step C to the first part 56 of the conduit 40 with the collar 64.

[0126] Then during a step D, the turbomachine 20 is aligned with the power transmission device 18. Then during a step E, the turbomachine 20 is moved towards the power transmission device 18 in the axial direction A by a distance corresponding to the determined stroke L, according to the position of [Fig.5]. Finally, during a step F, the turbomachine 20 is coupled with the power transmission device 18.

[0127] The invention makes it possible to considerably simplify the maintenance operations of an aircraft turbomachine 20, in particular a helicopter.

Claims

Claims

1. Particle trap (28) for an aircraft turbomachine (20), said particle trap (28) comprising: - an enclosure (32) configured to be connected to an air inlet of said turbomachine, - a first conduit (34) extending substantially along an axis B which is connected to said enclosure (32) and which has a first passage section (SI), - a plurality of injectors (36) mounted in the first conduit (34) and capable of being supplied with pressurized air, and - a second conduit (40) of axis B, one upstream end (42) of which is engaged in a sealed manner in the first conduit (34) downstream of said injectors (36), said second conduit (40) comprising from upstream to downstream • a first axial section (46) which has a passage section decreasing from the first passage section (SI) to a second passage section (S2), • a second axial section (48) continuously presenting the second passage section (S2), and • a third axial section (50) which has a passage section increasing from the second passage section (S2) to a third passage section (S3), the second conduit (40) comprising from upstream to downstream first and second parts (56, 58) which are separable at one end of the second section (48), characterized in that the first and second parts (56, 58) each respectively comprise at least one first flange (60) and one second flange (62) which extend transversely relative to the axis B, and in that said first and second flanges (60, 62) are of the same transverse size and are clamped against each other by a collar (64) having at least one concave axial section which covers at least edges (74, 76) of said first and second flanges (60, 62).

2. Particle trap (28) according to the preceding claim, characterized in that the first part (56) comprises the first section (46) and in that the second part (58) comprises the second and third sections (48, 50), the two parts being separable at the junction of the first and second sections (46, 48).

3. Particle trap (28) according to claim 1 or 2, characterized in that the first flange (60) has a transverse dimension which is greater than the first passage section (SI), said first flange (60) being capable of being received axially in abutment against a downstream end (66) of the first conduit (34).

4. Particle trap (28) according to the preceding claim, characterized in that the first conduit (34) carries, set back from its downstream end (66), a third flange (68) extending transversely relative to the axis B, and in that the first, second and third flanges (60, 62, 68) are of the same transverse size and clamped together by the collar (64).

5. Particle trap (28) according to the preceding claim, characterized in that: - the first and second flanges (60, 62) are shaped in the form of first and second collars which extend transversely with respect to the axis B and whose contact faces (70, 72) are arranged against each other, - each of the first and second collars comprises the two edges (74, 76) which are transversely opposite and in an arc of a circle and, on a face opposite its contact face (70, 72), first and second associated beads (78, 80), transversely opposite and in an arc of a circle, which match said edges (74, 76), - the third flange (68) comprises two third beads (82) in an arc of a circle, transversely opposite, which are arranged in contact with the first beads (78), and - the collar (64) comprises at least two transversely opposite arcuate sections (88) which cover the first to third beads (78, 80,82) and hold them tight against each other, and which are held tight by cladding (90).,

6. Particle trap (28) according to the preceding claim, characterized in that the first and third beads (78, 82) are tubular and each have a section open towards the axis B, each bead (78, 82) comprising an annular wall (84, 86) transverse to the axis B bearing on an annular wall (84, 86) transverse to the other bead.

7. Particle trap (28) according to the preceding claim, characterized in that the transverse annular wall (84) of the first bead (78) comprises an internal end (92) shaped into a pad configured to guide said first bead (78) on the downstream end (66) of the first conduit (34).

8. Particle trap (28) according to one of claims 3 to 7, characterized in that the first flange (60) comprises an annular elastic seal, which is carried by a face (98) of the first flange opposite its contact face (70) and which is interposed between the first collar (60) of the first flange and the downstream end (66) of the first conduit (34).

9. Particle trap according to claim 5, characterized in that the cladding (90) comprises at least two strips (100) enclosing the two sections (88) of the collar (64), which are connected at their free ends by tie rods (102) of adjustable length.

10. Particle trap (28) according to one of the preceding claims, characterized in that each conduit (34, 40) has an oblong cross-section extending along a main axis of elongation (T) with two opposite semi-cylindrical walls along said main axis (T).

11. Aircraft turbomachine (20) extending substantially in an axial direction A, and comprising at least one air inlet (30), characterized in that it comprises a particle trap (28) according to one of the preceding claims, the first and second ducts (34, 40) of this particle trap (28) extending in the axial direction B parallel to the axial direction A, and laterally along the turbomachine (20).

12. Aircraft comprising a powertrain (10) comprising: - a turbomachine (20) according to the preceding claim, - a power transmission device (18) placed upstream of the turbomachine (20) and coupled to said turbomachine, and - an engine compartment (12) comprising a firewall (16), which is arranged downstream of the turbomachine (20) and which comprises a convergent extraction duct (52) which is aligned with a free end (54) of the second duct (40) and which has an inlet section (S4) greater than the third passage section (S3) of the third section (50) of the second duct (40).

13. Method for extracting a turbomachine (20) from an aircraft according to the preceding claim, said turbomachine (20) being coupled to the power transmission device (18) via a shaft (26) capable of being extracted according to a determined stroke (L) in the axial direction A, and the free end (54) of the second conduit (40) being arranged at a determined distance (1) from the extraction conduit (52) which is less than said determined stroke (L), characterized in that it comprises the following steps: a) decoupling the turbomachine (20) from the power transmission device (18), b) separating the turbomachine (20) from the power transmission device (18) by moving the turbomachine (20) back in the axial direction A by a distance greater than the determined stroke (L) until the second part (58) of the second duct enters the extraction duct (52) and comes into abutment there, c) separating the first and second parts (56, 58) of the second duct (40), d) extracting the turbomachine (20) from the engine compartment (12) substantially transversely relative to the axial direction A, the second part (58) of the second duct (40) remaining in the extraction duct (52).

14. Method for mounting / remounting a turbomachine (20) of an aircraft according to claim 13, said turbomachine (20) being able to be coupled to the power transmission device (18) by means of a shaft (20) able to be introduced according to a determined stroke (L) in the axial direction A, and the free end (54) of the second duct (40) being able to be arranged at a determined distance (1) from the extraction duct which is less than said determined stroke, characterized in that it comprises the following steps: A) placing the second part (58) of the second duct (40) in the extraction duct (52), B) inserting the turbomachine (20) into the engine compartment (12) substantially transversely with respect to the axial direction A, by aligning the second part (58) of the second duct (40) with the first part (56) of the second duct (58),C) fixing the second part (58) of the second duct (40) to the first part (56) of the second duct, D) aligning the turbomachine (20) with the power transmission device (18) in the axial direction A, E) moving the turbomachine (20) towards the power transmission device (18) in the axial direction A by a cor- distance, corresponding to the determined race (L), F) coupling the turbomachine (20) with the power transmission device (18).

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