PART INCLUDING A FIRE BARRIER

Abstract

The invention relates to a component (11) for an aircraft turbomachine, the component (11) comprising: - a body (12) comprising a composite material including an organic matrix and fibers embedded in the matrix, and - a fire barrier (13) arranged on at least one surface of the body (12), characterized in that the fire barrier (13) is multilayered and comprises: - a first perforated layer (14) comprising glass fibers, and - a second layer (15) comprising fibers other than glass fibers, the first layer (14) being located between the body (12) and the second layer (15). Abstract figure: Figure 2

Description

Title of the invention: PART INCLUDING A FIRE BARRIER Technical field of the invention

[0001] The invention relates to the technical field of parts comprising a body made of organic matrix composite material and a fire barrier.

[0002] The invention relates in particular to aircraft turbomachine parts. Technical background

[0003] Among composite materials, organic matrix composite materials, also known by the acronym "OMC", are well known. These composite materials typically comprise an organic matrix and fibers embedded in the organic matrix.

[0004] Such composite materials exhibit good mechanical strength and low density compared to metallic materials such as steel. Given these advantageous properties, these materials are increasingly preferred in the aeronautical field. It is already known to equip aircraft turbomachinery with parts made of organic matrix composite material.

[0005] An aircraft turbomachine typically extends around and along a longitudinal axis. It comprises, from upstream to downstream in the direction of gas flow along the longitudinal axis, an upstream zone, also called the fan zone, in which a fan is arranged, and a downstream zone in which a low-pressure compressor, a high-pressure compressor, at least one combustion chamber, a high-pressure turbine, and a low-pressure turbine are arranged.

[0006] The downstream zone is an area where temperatures can reach several hundred degrees, even up to 1500°C. Therefore, parts located in this downstream zone, such as housings, must withstand such temperatures. Furthermore, the blower zone, like the downstream zone, is a fire hazard area where a fire is likely to spread. Thus, parts located in this blower zone must also withstand high temperatures.

[0007] However, parts comprising a body made of organic matrix composite material are not resistant to high temperatures, and such materials are likely to degrade rapidly in a high-temperature environment such as the downstream area. Furthermore, due to their low thermal resistance, such parts must have additional safety features for use in areas of the turbomachine subject to fire hazards.

[0008] In this context, it has been proposed to equip these parts with a fire barrier for to protect the composite material body from thermal degradation and to allow their implementation in the downstream or blower zone.

[0009] Document FR-B1-3 016 187 describes a part, in particular a blower housing, having a body made of composite material comprising a matrix and fibers embedded in the matrix. According to this document, the part further comprises a fire barrier comprising sheets of glass fibers pre-impregnated with a polymerized resin. The resin is, for example, an epoxy resin, a phenolic resin, or a cyanate ester resin. The sheets of glass fibers embedded in the resin form a sacrificial fire-resistant layer. Indeed, under the effect of the temperature increase, for example during a fire, the resin degrades, creating a thermally insulating air gap. It is therefore the degradation of the resin that protects the body of the part against thermal attack.

[0010] Although such a fire barrier helps limit damage to the composite material body in the event of a temperature increase, it is not entirely satisfactory. Indeed, such a fire barrier must be quite thick to limit thermal damage to the composite material body, which tends to increase the mass and size of the part.

[0011] There is therefore a need to provide a part comprising a body made of organic matrix composite material that can be used in an environment subject to a risk of fire and / or high temperatures, which is lightweight, compact, easy to manufacture and inexpensive. Summary of the invention

[0012] To this end, the invention proposes a part for an aircraft turbomachine, the part comprising:

[0013] - a body comprising a composite material comprising an organic matrix and fibers embedded in the matrix, and

[0014] - a fire barrier arranged on at least one surface of the body.

[0015] The part is remarkable in that the fire barrier is multi-layered and comprises

[0016] - a first perforated layer comprising glass fibers, and

[0017] - a second layer comprising fibers other than glass fibers,

[0018] the first layer being located between the body and the second layer.

[0019] Thanks to the first and second layers of the fire barrier, and in particular, thanks to the different nature of the fibers in the first and second layers, in the event of fire and / or a sharp increase in temperature, the first and second layers undergo different thermal expansions, causing them to separate at their interface. This separation allows the creation of an air gap between the first and second layers allow thermal insulation of the body of the part and therefore slow down the degradation of the part in case of fire for example.

[0020] Furthermore, thanks to the openwork nature of the first layer, the separation between the first and second layers is localized at the interfaces where the first layer is not openwork. This limits the risk of degradation of the fire barrier due to complete delamination of the first and second layers of the fire barrier.

[0021] Thanks to the fire barrier of the invention, it is possible to slow down the thermal attacks that the body of the part is likely to undergo without considerably increasing the thickness and therefore the mass and bulk of the part.

[0022] The invention may comprise one or more of the following features, taken individually or in combination with each other:

[0023] - the second layer comprises carbon fibers,

[0024] - the first layer has regularly distributed openings in this first layer, the openness rate being between 30% and 50%,

[0025] - the first layer further comprises a fluorinated polymer material,

[0026] - the fluorinated polymer is polytetrafluoroethylene,

[0027] - the fire barrier further comprises:

[0028] - a third perforated layer comprising glass fibers, and

[0029] - a fourth layer comprising fibers other than glass fibers, the the third layer being located between the second layer and the fourth layer,

[0030] - the third layer has regularly distributed openings in this third layer, the openings of the first layer being offset relative to the openings of the third layer,

[0031] - the fire barrier further comprises a casing fixed to the body, the first and The second layer being located between the outer layer and the body,

[0032] - the casing has a central part and two connecting flanges fixed to the body, the first and second layers being located between the central part and the body,

[0033] - the envelope (18) comprises woven fibers,

[0034] — the fibers are chosen from glass, carbon, ceramic fibers or a a mixture of these,

[0035] — the first layer comprises a circular patterned armor including circles defining the openings,

[0036] — the third layer comprises a circular patterned armor comprising circles delimiting the openings, the circles of the first layer each having an axis that extends into the corresponding openings of the third layer,

[0037] — the axes of the openings of the first layer extend into the circles of the third layer. Brief description of the figures

[0038] Other features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings in which:

[0039] [Fig. 1] is a schematic perspective representation of an aircraft turbomachine to which the invention can be applied,

[0040] [Fig.2] is a schematic cross-sectional representation of a part according to the invention,

[0041] [Fig. 3] is another schematic cross-sectional representation of a part according to the invention,

[0042] [Fig.4] is a top view of the first or third layer of the fire barrier,

[0043] [Fig. 5] is a top view of the first and third layers,

[0044] [Fig.6] is a cross-sectional view passing through plane AA of [Fig.5],

[0045] [Fig. 7] is a block diagram of a manufacturing process for the part of the invention. Detailed description of the invention

[0046] An example of a turbomachine 1 for an aircraft and to which the invention can be applied is shown in [Fig. 1].

[0047] The invention can be applied to any type of turbomachine parts for which protection against an increase in temperature or even fire is required.

[0048] The turbomachine 1 extends around and along a longitudinal axis A.

[0049] Turbomachine 1 is, for example, a turbojet engine. It comprises, from upstream to downstream along the longitudinal axis A in the direction of gas flow F in the turbomachine 1, a blower 2, at least one compressor 3 such as a low pressure compressor and a high pressure compressor, a combustion chamber 4, at least one turbine 5 such as a high pressure turbine and a low pressure turbine, and a gas exhaust nozzle.

[0050] The low-pressure and high-pressure compressors and the high-pressure and low-pressure turbines each comprise at least one rotor. The rotor of the low-pressure compressor is connected to the rotor of the low-pressure turbine by a low-pressure shaft, and the rotor of the high-pressure compressor is connected to the rotor of the high-pressure turbine by a high-pressure shaft. The high-pressure shaft is centered on the longitudinal axis A and arranged coaxially around the low-pressure shaft.

[0051] The fan 2 comprises a disc 6 that rotates about the longitudinal axis A and blades 7 extending radially from the disc. The fan 2 further comprises a fan shaft (not shown) connected to the low-pressure shaft via, for example, a speed reducer. The fan 2 is of the ducted type. The tur- The machine 1 also includes a blower housing 8. The blower housing 8 is annular and centered on the longitudinal axis A. It is arranged around the blades 7. The blower housing 8 delimits a blower zone.

[0052] Advantageously, the turbomachine 1 further comprises an intermediate casing 9 arranged downstream of the blower casing 8. It is connected to the blower casing 8, for example, by flanges. The intermediate casing 9 is annular, centered on the longitudinal axis A, and delimits an intermediate zone in which the low-pressure compressor can be located.

[0053] The turbomachine 1 further includes a downstream casing 10 arranged downstream of the blower casing 8 and the intermediate casing 9. The downstream casing 10 extends around the high-pressure compressor, the combustion chamber 4 and the turbine 5. The downstream casing 10 is annular, centered on the longitudinal axis A and delimits a downstream zone.

[0054] The temperature within the downstream zone is between 100°C and 1500°C, in particular due to the presence of the combustion chamber 4. Furthermore, due in particular to the risk of fire within the blower zone and the intermediate zone, it is required that the blower housing 8 and the intermediate housing 9 be able to withstand temperatures up to 1100°C.

[0055] With reference to Figures 2 and 3, the turbomachine 1 is equipped with parts 11 comprising a body 12 made of a first composite material. These parts 11 can form one of the casings 8, 9, 10 of the turbomachine 1 or be arranged within one of the zones of the turbomachine 1, such as the fan, intermediate, or downstream zone. Each part 11 can be of revolution or planar. It can have an annular, tubular, polygonal, or any other shape depending on its application.

[0056] The first composite material of the body 12 comprises a matrix and fibers embedded in the matrix. The matrix is ​​of an organic type. The organic material of the matrix is ​​a polymer selected from thermoplastics or thermosets, or a mixture thereof. The thermoplastic polymer is, for example, selected from polyolefins such as polypropylene, polyethylene, fluoropolymers, or polyaryletherketones such as polyetheretherketone, or a mixture thereof. The thermosetting polymer is, for example, selected from epoxy resins.

[0057] The fibers are, for example, selected from carbon fibers, glass fibers, or aramid fibers. The fibers are, for example, woven. They are, for example, organized in the form of a three-dimensional fibrous preform.

[0058] Part 11 further includes a fire barrier 13 arranged on at least one surface of the body 12.

[0059] Advantageously, the fire barrier 13 has a thickness e of between 2 mm and 3 mm. The thickness e of the fire barrier 13 is less than the thickness of the body 12.

[0060] The fire barrier 13 extends along three directions D1, D2, D3, which are perpendicular to each other. The thickness e of the fire barrier 13 is measured along the third direction D3. The fire barrier 13 has two surfaces opposite and parallel to the surface of the body 12. The two opposite surfaces are parallel to the first and second directions D1, D2 and are perpendicular to the third direction D3.

[0061] The fire barrier 13 is multilayered. According to the invention, the fire barrier 13 comprises a first layer 14 and a second layer 15, and optionally third and fourth layers 16, 17. The fire barrier 13 may further comprise a casing 18.

[0062] The first layer 14 is located between the second layer 15 and the body 12. Advantageously, the first layer 14 is directly arranged on the surface of the body 12.

[0063] The first layer 14 advantageously has a thickness between 200 pm and 500 pm, preferably between 250 pm and 350 pm.

[0064] According to the invention, the first layer 14 comprises glass fibers. The glass fibers have a diameter between 5 pm and 10 pm, preferably between 6 pm and 10 pm.

[0065] Advantageously, the glass fibers are woven.

[0066] The first layer 14 advantageously comprises a fluoropolymer material. The fluoropolymer is preferably polytetrafluoroethylene (PTFE). The glass fibers are, for example, coated or impregnated with the fluoropolymer material. Preferably, the glass fibers are impregnated with the fluoropolymer after weaving.

[0067] The first layer 14 is, according to the invention, perforated. It has openings 14a and a reinforcement 14b carrying the openings 14a. The openings 14a are regularly distributed in the first layer 14. Preferably, the first layer 14 has an openness ratio of between 10% and 60%, preferably between 30% and 50%, the openness ratio being understood as the ratio between the cumulative surface area of ​​the openings and the total surface area of ​​the first layer 14. The openings 14a are through-holes. They open on both sides of the first layer 14. Each opening 14a has an axis parallel to the third direction D3.

[0068] As more clearly seen in [Fig. 4], each opening 14a has, for example, a star shape, preferably with four points. Each opening 14a is delimited by the weave 14b. Each opening 14a has a dimension between 10 mm and 70 mm, preferably between 30 mm and 50 mm. The openings 14a are advantageously arranged in rows and columns. The openings 14a are thus aligned along the first and second perpendicular directions D1, D2. The weave 14b has a pattern complementary to the openings 14a. The weave 14b thus has, for example, a circular pattern. Each circle 14b' of the weave 14b has a diameter between 10 mm and 70 mm, preferably between 30 mm and 50 mm. The circles 14b' are advantageously arranged in rows and columns. The circles 14b' are thus aligned along the first and second perpendicular directions D1, D2. The dimension of the circles 14b' is identical to the dimension of the openings 14a.

[0069] Each circle 14b' has an axis extending parallel to the third direction D3.

[0070] The armor 14b could feature a polygonal pattern, for example in the shape of a diamond, a hexagon or even a wave-shaped pattern.

[0071] The second layer 15 is arranged on the first layer 14. The second layer 15 advantageously has a thickness between 100 pm and 600 pm, advantageously between 400 pm and 600 pm, preferably between 450 pm and 550 pm.

[0072] The second layer 15 advantageously has at least two edges 15a, 15b for connection with the body 12 of the part 11. The two edges 15a, 15b are for example directly connected to the body 12 by bonding or co-molding.

[0073] According to the invention, the second layer 15 comprises fibers other than glass fibers, and preferably comprises carbon fibers. The carbon fibers have a diameter of between 5 µm and 15 µm, preferably between 5 µm and 10 µm.

[0074] Advantageously, the carbon fibers are woven.

[0075] Advantageously, the second layer 15 comprises at least one ply, and preferably, a plurality of ply. Each ply comprises bidirectional or unidirectional fibers. When the second layer 15 has ply of bidirectional fibers, the thickness of the second layer 15 is between 450 µm and 550 µm. When the second layer 15 has ply of unidirectional fibers, the thickness of the second layer 15 is between 100 µm and 200 µm.

[0076] Thanks to the first and second layers 14, 15 of the fire barrier 13, it is possible to limit the thermal attacks that the body 12 of the part 11 is likely to undergo. In particular, due to the different nature of the fibers in the first and second layers 14, 15, in the event of fire or a sharp temperature increase, the first and second layers 14, 15 will undergo different thermal expansions, causing delamination at the interface between the first and second layers 14, 15. This delamination is localized between the armor 14b of the first layer 14 and the second layer 15 in contact with the armor 14b. This localized delamination allows the creation of air gaps between the first and second layers 14, 15, thus thermally insulating the body 12 of the part 11 and slowing down potential thermal degradation.

[0077] Furthermore, the openings 14a in the first layer 14 advantageously control the delamination at the interface of the first and second layers 14, 15. Indeed, the openings 14a limit the delamination of the second layer 15 in order to maintain cohesion of the fire barrier 13 and effective protection against fire and / or temperature.

[0078] Advantageously, the second layer 15 is located between the third layer 16 and the first layer 14. The third layer 16 is advantageously identical to the first layer 14.

[0079] The third layer 16 advantageously has a thickness of between 200 µm and 500 µm, preferably between 250 µm and 350 µm. The thickness of the third layer 16 is advantageously identical to the thickness of the first layer 14.

[0080] The third layer 16 comprises glass fibers. The glass fibers have a diameter between 5 pm and 10 pm, preferably between 6 pm and 10 pm.

[0081] Advantageously, the glass fibers are woven.

[0082] The third layer 16 advantageously comprises a fluoropolymer material. The fluoropolymer is preferably polytetrafluoroethylene (PTFE). The glass fibers are, for example, coated or impregnated with the fluoropolymer material. Preferably, the glass fibers are impregnated with the fluoropolymer after weaving.

[0083] The third layer 16 is preferably perforated. It has openings 16a and an armor 16b bearing the openings 16a. The openings 16a are regularly distributed in the third layer 16. Preferably, the third layer 16 has an opening ratio of between 10% and 60%, preferably between 30% and 50%, the opening ratio being understood as the ratio between the cumulative area of ​​the openings and the total area of ​​the third layer 16. The openings 16a are through-holes. They open on both sides of the third layer 16. Each opening 16a has an axis parallel to the third direction D3.

[0084] As more clearly seen in [Fig. 4], each opening 16a has a star shape, preferably with four points. Each opening 16a is delimited by the armor 16b. Each opening 16a has a dimension between 10 mm and 70 mm, preferably between 30 mm and 50 mm. The openings 16a are advantageously arranged in rows and columns. The openings 16a are thus aligned along the two perpendicular directions D1, D2.

[0085] The armature 16b has a pattern that complements the openings 16a. The armature 16b thus has a circular pattern. Each circle 16b' of the armature 16b has a diameter between 10 mm and 70 mm, preferably between 30 mm and 50 mm. The dimensions of the circles 16b' are identical to the dimensions of the openings 16a.

[0086] The circles 16b' are advantageously arranged in rows and columns. The circles 16b' are thus aligned along the two perpendicular directions D1, D2.

[0087] Each circle 16b' has an axis parallel to the third direction D3.

[0088] The 16b armor could have a polygonal pattern, for example in the shape of diamond, hexagon or even a wave-shaped pattern.

[0089] As illustrated in Figures 5 and 6, according to an advantageous embodiment, the openings 14a of the first layer 14 are offset with respect to the openings 16a of the third layer 16. Preferably, the axes of the circles 14b' of the first layer 14 extend into the corresponding openings 16a of the third layer 16 and the axes of the openings 14a of the first layer 14 extend into the circles 16b' of the third layer 16. The openings 14a of the first layer 14 are thus aligned with the circles 16b' of the weave 16b of the third layer 16 along the third direction D3 and the circles 14b' of the first layer 14 are aligned with the openings 16a of the third layer 16 along the third direction D3. This allows for alternating delamination zones and the creation of multiple air cavities in case of fire, for example. Such a configuration prevents complete delamination of the layers of the fire barrier 13.

[0090] Advantageously, the third layer 16 is located between the second layer 15 and the fourth layer 17. The fourth layer 17 can be identical to the second layer 15.

[0091] The fourth layer 17 advantageously has a thickness between 100 pm and 600 pm, advantageously between 400 pm and 600 pm, preferably between 450 pm and 550 pm.

[0092] The fourth layer 17 advantageously has at least two edges 17a, 17b of connection with the envelope 18 or with the second layer 15. The two edges 17a, 17b are for example directly connected to the edges 15a, 15b of the second layer 15. The edges 17a, 17b, 15a, 15b of the second and fourth layers 15, 17 are aligned along the third direction D3, in other words in the direction of the thickness e of the fire barrier 13.

[0093] The fourth layer 17 comprises fibers other than glass fibers, and preferably carbon fibers. The carbon fibers have a diameter between 5 pm and 15 pm, preferably between 5 pm and 15 pm, preferably between 5 pm and 10 pm.

[0094] Advantageously, the carbon fibers are woven.

[0095] Advantageously, the fourth layer 17 comprises at least one ply, and preferably, a plurality of ply. Each ply comprises bidirectional or unidirectional fibers. When the fourth layer 17 has ply of bidirectional fibers, the thickness of the fourth layer 17 is between 450 µm and 550 µm. When the fourth layer 17 has ply of unidirectional fibers, the thickness of the fourth layer 17 is between 100 µm and 200 µm.

[0096] The fire barrier 13 may comprise a superposition of the first, second, third, and fourth layers 14, 15, 16, 17 described above. For example, the fire barrier 13 may comprise a fifth layer identical to the first layer 14 and a sixth layer identical to the second layer 15. The fifth layer is located between the sixth layer and the fourth layer and the sixth layer being located between the envelope 18 and the fifth layer.

[0097] The third and fourth layers 16, 17 improve the effectiveness of the fire barrier 13 by increasing the thickness of the air gaps, which thermally insulate the body 12 in the event of a sharp increase in temperature or even fire.

[0098] Advantageously, the first, second, third and fourth layers 14, 15, 16, 17 are located between the body 12 of the part 11 and the envelope 18.

[0099] The envelope 18 has a thickness between 200 pm and 500 pm, preferably between 250 pm and 350 pm.

[0100] The casing 18 comprises fibers. The fibers are preferably selected from carbon, glass, ceramic fibers or a mixture thereof. The fibers are preferably woven.

[0101] The envelope 18 advantageously has a central part 18a and two connecting flanges 18b, 18c bordering the central part 18a.

[0102] The connecting flanges 18b, 18c are directly fixed to the body 12 of the part 11. They are fixed for example by bonding or co-molding.

[0103] The casing 18 improves the attachment of the fire barrier 13 to the body 12 of the part 11. In particular, the connecting flanges 18b, 18c limit the risk of the fire barrier 13 detaching in the event of a fire. Since the first and second layers 14, 15 are located outside the connecting flanges 18b, 18c, the delamination of the fire barrier 13 in the event of a fire is contained within the central portion 18a of the casing 18.

[0104] The first, second, third and fourth layers 14, 15, 16, 17 are located between the body 12 of the part 11 and the central part 18a of the envelope 18.

[0105] A manufacturing process for part 11 will now be described with reference to [Fig.7].

[0106] The manufacturing process comprises the following steps:

[0107] (a) place the fibers of body 12 in a mold,

[0108] (b) place the glass fibers of the first layer 14 in the mold,

[0109] (c) place the carbon fibres of the second layer 15 in the mold,

[0110] (d) optionally place the glass fibers of the third layer 16 in the mold,

[0111] (e) optionally place the carbon fibres of the fourth layer 17 in the mold,

[0112] (f) optionally place the fibers of the envelope 18 in the mold.

[0113] In steps (a), (b), (c), (d), (e) and (f), the fibers are woven, for example.

[0114] According to a first embodiment, the fibers are pre-impregnated. According to this embodiment, After step (f), the process includes a step (g) of resin polymerization. By For example, the mold is placed under vacuum and in an autoclave for resin polymerization.

[0115] According to another embodiment, the process comprises, after steps (a), (b), (c), (d), (e) and (f), a step (g') of injecting a resin into the mold and a step (h) of polymerizing the resin. In step (h), the mold is, for example, placed in an oven.

Claims

Claims

1. Part (11) for an aircraft turbomachine (1), the part (11) comprising: - a body (12) comprising a composite material comprising an organic matrix and fibers embedded in the matrix, and - a fire barrier (13) arranged on at least one surface of the body (12), characterized in that the fire barrier (13) is multi-layered and comprises: - a first perforated layer (14) comprising glass fibers, and - a second layer (15) comprising fibers other than the glass fibers, the first layer (14) being located between the body (12) and the second layer (15).

2. Part according to the preceding claim, characterized in that the second layer (15) comprises carbon fibers.

3. Part according to any one of the preceding claims, characterized in that the first layer (14) has openings (14a) regularly distributed in this first layer (14), the opening rate being between 30% and 50%.

4. Part according to any one of the preceding claims, characterized in that the first layer (14) further comprises a fluoropolymer material.

5. Part according to the preceding claim, characterized in that the fluorinated polymer is polytetrafluoroethylene.

6. Part according to any one of the preceding claims, characterized in that the fire barrier (13) further comprises: - a third perforated layer (16) comprising glass fibers, and - a fourth layer (17) comprising fibers other than the glass fibers, the third layer (16) being located between the second layer (15) and the fourth layer (17).

7. Part according to the preceding claim, characterized in that the third layer (16) has openings (16a) regularly distributed in this third layer (16), the openings (14a) of the first layer (14) being offset relative to the openings (16a) of the third layer (16).

8. Part according to any one of the preceding claims, ca- characterized in that the fire barrier (13) further comprises a casing (18) attached to the body (12), the first and second layers (14, 15) being located between the casing (18) and the body (12).

9. Part according to the preceding claim, characterized in that the envelope (18) has a central part (18a) and two connecting flanges (18b, 18c) fixed to the body (12), the first and second layers (14, 15) being located between the central part (18a) and the body (12).

10. Part according to one of claims 8 or 9, characterized in that the envelope (18) comprises woven fibers.

Images