The invention is in the field of turbine engines fitted to particular aircraft or helicopters.

It relates more precisely a particulate trapping device for turbomachines, in particular these particles are grains of sand or dust contained in an air stream flowing within said turbomachine. This trapping device is more particularly intended to be disposed in the bypass area of ​​a turbomachine combustion chamber.

The invention also relates to a turbomachine fitted with such a trapping device.

STATE OF THE ART

As can be seen in the diagram of Figure 1 attached, a turbomachine 1 generally comprises, from upstream to downstream in the direction of gas flow, an air outlet 1 1, one or more compressor stages 12 (e.g. one in said figure), an annular combustion chamber 13, one or more turbine stages, e.g., a high pressure turbine 14 and a low pressure turbine 15, and finally a nozzle 16 exhaust gases.

In the following description and claims and in the figures, the terms "front" (reference AV) and "rear" (CA reference) are used with reference to the disposition of the turbine engine on the aircraft or helicopter .

The air is sucked in the air intake Level 1 1 is compressed in compressor 12 and then is directed into the bypass area 17 of the combustion chamber 13.

During operation of the turbomachine, the walls 131 of the combustion chamber 13 are subjected to very high temperatures. The cooling of these walls is then usually provided by the flow of air leaving the compressor 12, through a multi-hole, that is to say, many holes of very small diameter, formed in the walls 131 of said combustion chamber.

Only a few of these holes, referenced 130, are shown in Figure 1.

The hot air and combustion gases exiting the combustor 13 are then sent to the turbines 14, 15 and the exhaust nozzle 16.

However, it was found that when the apparatus equipped with said turbine engine is flying in a dusty or sandy atmosphere, for example in a desert, particle cloud P, such as grains of sand and dust, are ingested at of the air outlet 11.

These P particles then pass into the bypass zone 17 and eventually block the holes 130 in the walls 131 of the combustion chamber 13.

However, if the holes 130 are blocked, the air can not flow into the combustion chamber 13, the cooling of the walls 131 is no longer provided and the combustion chamber is rapidly degraded in a fire.

A known device for retaining particles P ingested by the turbomachine is an air inlet grille located at the air inlets 11, and which can retain a portion of the foreign body prior to penetration into the turbomachine.

However, P particles having a smaller size than the meshes of the grid are ingested.

It is not possible to install a filter with finer meshes, at the air intake, as this will cause excessive pressure drop and cause a drop in engine performance.

It is already known from document US 3,371,471, a particulate trapping device, intended to be placed at the air inlet of a gas turbine engine. Such a device comprises a series of curved baffles that the incoming airflow impinges. The particles retained by these baffles are collected in an annular dust collection device.

However, such a device is not compact and is not intended to be installed in the bypass area of ​​a turbomachine combustion chamber.

In addition, the baffles have the effect of slowing the flow of air flow and cause substantial pressure drop.

PRESENTATION OF THE INVENTION

The invention therefore aims to solve the aforementioned drawbacks of the prior art and to provide a particulate trapping device, which enables to retain them or at least a large part thereof, before that they do not obstruct the holes in the combustion chamber walls.

Another object of the invention is to provide such a trapping device, which does not affect the performance of operation of the turbine engine, including that does not alter the flow of air inside of it.

Another object of the invention is to provide a compact trapping device.

Finally, advantageously, such a trapping device should also allow temporary storage of trapped particles and their removal during maintenance operations of the turbomachine and that, to avoid an accumulation of these particles in the trapping device.

To this end, the invention relates to a particulate trap device for a turbomachine, in particular these particles are grains of sand or dust contained in a flow of air circulating inside of a turbomachine, in particular the flow of air flowing in the bypass region of the said turbomachine combustion chamber.

According to the invention, this device comprises:

- at least two deflectors particles,

- an element for collecting and storing particles deflected by said deflector,

- fastening means of said trapping device on a portion of the turbomachine,

said baffles being of annular shape and being attached to at least one supporting frame, so as to be coaxial, to be aligned radially and be radially spaced from each other or one another, said baffles being inclined in the same direction relative to their axes of revolution so as to be rotated to said collection element and storage of the particles.

Thanks to these characteristics of the invention, all particles which abut against the one or more baffle (s) are returned to the element collection and storage of the particles and no longer close off the holes in the wall of the chamber combustion.

This device also has the advantage of being very compact.

According to other advantageous characteristics and not restrictive of the invention, taken alone or in combination:

- said support frame is a ring which extends in a plane perpendicular or substantially perpendicular to the axis of revolution of the baffles, the baffles of a pair of adjacent deflectors are attached respectively along the outer circular edge and the circular edge said inner annular frame support and this support frame is formed with airflow openings;

- the inner surface of a deflector presents an angle of inclination relative to said axis of revolution greater than the angle of inclination with respect to the same axis of revolution of the inner surface of a deflector arranged radially further in inside the device;

- the inner radius of the outermost baffle of a pair of adjacent baffles is less than or equal to the outer radius of a baffle located innermost;

- the device comprises three baffles;

- at least one of said baffles has a cross section rectilinear;

- at least one of said baffles has a curved cross-section whose concavity is turned towards the element collection and storage of the particles;

- the collection element and storage comprises a solid ring coaxial to the axis of revolution of the deflector and extends in a plane perpendicular or substantially perpendicular to this axis, this ring being extended towards said deflector by an annular rim solid surface and with a solid interior annular rim, said member of collection and storage being arranged facing the deflector;

- said securing means comprises an annular flange coaxial plane to the axis of revolution of the deflectors and perpendicular thereto and which is extended toward the collection element and storage of the particles, by a cylinder with a longitudinal axis coaxial with said axis of revolution, in that said cylinder is pierced by several passage openings of the air flow and in that said annular flange is drilled with several holes for the passage of fasteners.

Finally, the invention also relates to a turbomachine comprising a combustion chamber and a bypass zone formed between the wall of said combustion chamber and an outer casing of said turbomachine, the turbomachine being equipped with the above-mentioned particle trapping device.

PRESENTATION DES FIGURES

Other features and advantages of the invention will become apparent from the description will now be made with reference to the accompanying drawings, which show, as non-limiting indication, a possible embodiment.

In these drawings:

- Figure 1 is a schematic view in longitudinal section of an embodiment of a turbomachine,

- Figure 2 is a view of detail A of Figure 1, on which further shows the trapping device according to the invention,

- Figures 3, 4 and 5 are partial perspective views of an embodiment of the trapping device according to the invention, taken along three different viewing angles.

DETAILED DESCRIPTION

The particulate trapping device according to the invention is generally indicated 2.

As can be seen in Figure 2, the device 2 is intended to be positioned in the zone 17 to bypass the combustion chamber 13, more precisely outside the wall 131 of the combustion chamber 13 and the within the outer casing 18 of the turbomachine.

However, its precise position is determined by calculation, based on the trajectory of the particles contained in the airflow circulating inside this bypass area 17. This calculation also takes into account the respective shapes of the wall 131 and the wall portion 180 of the outer housing 18, next to the rear end of the combustion chamber 13.

The trapping device is thus advantageously arranged at the place where it will collect a maximum of particles before the latter reach the hole 130 of the wall of the combustion chamber.

A particular embodiment of this trapping device 2 will now be described with reference to Figures 2 to 5.

This trapping device 2 preferably comprises, from the front AV rearwardly AR, at least two baffles 3, an element 5 for the collection and storage of the particles and of fixing means 6 of the storage device on a portion of the turbine engine.

All these elements are made of a material which is heat resistant and preferably also abrasion particles, for example metal or a composite material.

These elements will be described in more detail.

The device comprises at least two baffles 3, for example three as shown in Figs. It could also have more than three deflectors.

Each deflector has the shape of a ring, the axis of revolution X, X '. The various deflectors 3 are fixed to a support frame 4, so as to be coaxial with an axis XX ', and radially spaced from each other.

In the example described and shown in Figure 3, these baffles are referred to as "external" baffles 3a, "median" and 3b "internal" 3c, the outer deflector being that of largest diameter and therefore located outermost . Each deflector is constituted by an element having the form of a solid strip of small width closed on itself in a ring shape.

All baffles 3a, 3b, 3c are also fixed on the frame 4 so as to be inclined in the same direction relative to their common axis of revolution XX ', that is to say to be inclined the outward and forward to the axis of revolution XX 'and rear AR. In other words, they have a form of frustoconical ring. However, their inclination angles are preferably different. These deflectors are turned towards the element 5.

Finally, the deflector 3, 3a, 3b, 3c are fixed on the frame 4 so as to be aligned radially and not to be offset along the axis X-X ', so as to not occupy a too important between the wall 130 of the

combustion chamber and the wall 180 of the housing and not to restrict the flow of the air flow flowing in this area.

The term "radial alignment" is meant that all of the deflectors 3a,

3b, 3c intersect a plane referenced P, perpendicular to their respective axes of revolution X-X ', these axes being coincident.

The inner face 30a of the external baffle 3a (that is to say the face turned towards the axis XX ') forms an angle a with the axis of revolution XX', the inner surface 30b of the medial deflector 3b, forms with the axis XX 'at an angle 6, and finally the inner face 30c of the internal baffle 3c forms an angle γ with the axis XX'. As can be seen in Figure 2, the angle a is greater than the angle β which is itself greater than the angle γ.

Preferably, the angle a is between 65 ° and 75 °, preferably equal to 70 °, the angle 6 is between 45 ° and 55 °, more preferably equal to 50 °, the angle γ is between 25 ° and 35 °, more preferably equal to 30 °.

Preferably, and as can be seen in Figure 2, baffles 3a, 3b and 3c have a rectilinear cross-section.

However, it could be curved with its concavity facing towards the element collection and storage 5 particles.

As best seen in Figures 2, 4 and 5, the frame 4 acts as a spacer between two adjacent deflectors. It has the shape of a ring extending in a plane perpendicular or substantially perpendicular to the axis of revolution XX ', for example the plane P. The frame 4 is pierced with openings 40 allowing passage of the flow 'air. These apertures 40 are advantageously distributed at regular intervals and preferably constitute a substantial part of the surface of the frame 4. They also help to lighten the frame.

In the case where the trapping device 2 comprises more than two baffles, for example three as in the figures, it then comprises a frame 4 between each wall adjacent baffles (see Fig. (5) The baffles of a pair of baffles contiguous are respectively fixed along the outer circumferential edge and the inner circular edge of the annular frame 4.

Advantageously, the deflector 3, 3a, 3b, 3c are fixed on the frames 4 by welding.

As best seen in Figures 2 and 4, preferably, the element 5 for the collection and storage of the particles comprises a full ring 50, coaxial to the axis of revolution XX 'baffles 3a to 3c and which extends in a plane perpendicular or substantially perpendicular to this axis.

Preferably there is a single collecting element 5 for all baffles 3, 3a, 3b, 3c.

This ring 50 is extended towards the front AV by an outer annular flange 51 and open by an inner annular flange 52 full.

Preferably, the inner annular flange 52 is located in the extension of the rear edge of the deflector 3c the innermost. Preferably, these two elements form one piece.

This element 5 therefore has the general form of a groove oriented in relation to the deflectors 3, 3a, 3b, 3c.

Finally, as best seen in FIGS 2 to 4, preferably, the fastening means 6 comprises an annular flange 60 planar, coaxial with the axis of revolution XX 'and baffles perpendicularly to said axis X-X' that extends forward by a cylinder 61 with a longitudinal axis X-X '.

The flange 60 is drilled with several holes 62 which allow the passage of fixing members 7 such as for example screws. The screws help secure the flange on a portion of the engine.

The cylinder 61 is pierced with a plurality of openings 63 allowing passage of the air flow circulating inside the turbine engine. Similarly to what has been described for frames 4, these openings 63 are an important part of the cylinder surface 61, so as not to inhibit or restrict the flow of air. They also help to reduce the overall weight of the device.

The cylinder 61 is linked to the element 5 of storage particles. Preferably, the cylinder 61 is welded to the inner end of the ring 50 of the element 5.

Operation of the device is as follows.

The air from the compressor 12, particulate laden P, penetrates inside of the bypass area 17, forward AV rearwardly AR between the outer radial wall 131 of the combustion chamber 13 and the housing 18 (arrow F in Figure 2).

This air flow charged with particles strikes the wall 180, so that the particles ricochet against it and then strike the outer faces 31 a, 31 b, 31 c of the deflectors 3a, 3b and 3c oriented towards this wall 180. the particles race is braked, these slide inwardly (toward the axis Χ-Χ '), along the deflectors to be gathered and collected in the element 5, where they can come out as the walls of it are full.

However, the openings 40 help limit the impact of the trapping device 2 on the circulation of the air flow and thus limit the pressure losses. In other words, the particles are retained by the element 5, but the air flow may continue to circulate around the outer walls 131 of the combustion chamber 13 to enter the holes 130 and provide the function cooling of these walls.

Finally, it is noted that, advantageously, the inner radius R1 of the outer deflector 3a (that is to say its smallest radius) is less than or equal to the outer radius R2 of the adjacent medial deflector 3b (that is, -dire its larger radius). It can be the same for each pair of adjacent baffles.

Thus, if a particle were to ricochet against the wall 180 of the housing 18 and turned back toward the front in a direction parallel to the axis X-X ', it is always mandatory trapped by the external baffle 3a.

particle trajectories of calculations must be performed for each turbine engine, depending on the shape of the walls delimiting the bypass area 17 of the combustion chamber, so as to position at best the particulate trap 2 so that the latter retains substantially all of the particles ingested by the turbomachine, and entering the bypass of the combustion chamber.

In addition, the values ​​of angles α, γ and 6 are also adjusted depending on the shape of the wall 180 and may be different from those mentioned previously.

During the maintenance of the turbine engine, the particles trapped in the element 5 can then be removed to avoid their accumulation.

CLAIMS

trapping device (2) for a turbomachine particles, these particles being in particular grains of sand or dust contained in a flow of air circulating inside of a turbomachine, in particular the air flow circulating in the area bypass the combustion chamber of said turbomachine, characterized in that it comprises:

- at least two deflectors of particles (3, 3a, 3b, 3c)

- an element (5) for collecting and storing the particles deflected by said deflector,

- means (6) for fixing said trapping device (2) on a portion of the turbomachine,

said deflectors (3, 3a, 3b, 3c) being annular and being fixed to at least one support frame (4) so ​​as to be coaxial, to be aligned radially and be radially spaced from each other or one another, said baffles (3, 3a, 3b, 3c) being inclined in the same direction relative to their axes of revolution (Χ-Χ ') so as to be turned towards said element (5) for collecting and storage of the particles.

Device according to Claim 1, characterized in that said support frame (4) is a ring which extends in a plane perpendicular or substantially perpendicular to the axis of revolution (Χ-Χ ') of the deflectors (3, 3a, 3b, 3c), in that the baffles of a pair of adjacent baffles are fixed along the outer circumference and the inner circular edge to edge respectively of said annular support frame (4) and in that this frame (4) support is pierced with openings (40) for passage of air flow. Device according to claim 1 or 2, characterized in that the inner surface of a deflector (3a, 3b) has an angle of inclination (α, β) relative to said axis of revolution (Χ-Χ ') greater than the angle of inclination (6,

Device according to one of the preceding claims, characterized in that the inner radius (R1) of the outermost baffle of a pair of adjacent baffles is less than or equal to the outer radius (R2) of a deflector located further inside.

5. Device according to one of the preceding claims, characterized in that it comprises three baffles (3a, 3b, 3c).

6. Device according to one of the preceding claims, characterized in that at least one of said deflectors (3, 3a, 3b, 3c) has a rectilinear cross-section.

7. Device according to one of claims 1 to 5, characterized in that at least one of said deflectors (3, 3a, 3b, 3c) has a curved cross-section whose concavity is turned towards the element (5 ) collection and storage of the particles.

8. Device according to one of the preceding claims, characterized in that the element (5) for collecting and storing comprises a full ring (50) coaxial with the axis of revolution (Χ-Χ ') of the deflectors (3 , 3a, 3b, 3c) and which extends in a plane perpendicular or substantially perpendicular to this axis, this ring (50) being extended towards said deflector by a solid outer annular flange (51) and with a solid interior annular rim (52), said element (5) of collection and storage being arranged facing the deflector.

9. Device according to one of the preceding claims, characterized in that said means (6) for fixing comprises a flat annular flange (60) coaxial with the axis of revolution (Χ-Χ ') of the deflectors (3, 3a, 3b, 3c) perpendicular thereto and which extends in the direction of the element (5) collection and storage of the particles, by a cylinder (61) having a longitudinal axis coaxial to said axis of revolution (Χ-Χ '), in that said cylinder (61) is pierced with a plurality of openings (63) for passage of the air flow and in that said annular flange (60) is drilled with several holes (62) passage of bodies fixing (7).

10. The turbomachine (1) comprising a combustion chamber (13) and a bypass region (17) formed between the wall (131) of said combustion chamber (13) and an outer casing (18) of said turbomachine, characterized in it is equipped with the particulate trapping device (2) according to any one of the preceding claims and in that said device (2) is disposed within said bypass zone (17).