Hybrid heat-resistant ventilation duct for aircraft.

Abstract

The invention relates to an aircraft comprising a ventilation duct (200) located at the boundary of a fire hazard zone (FHZ) of the aircraft. This ventilation duct (200) comprises a first flange (200a) intended to be located in the fire hazard zone (FHZ), a second duct (200b) with a second flange (200c) intended to be located in an adjacent zone (AZ). The ventilation duct (200) further comprises an intermediate layer (201) made of a composite material and located between the first flange (200a) and the second flange (200c), and fastening means for securing them together. Advantageously, the heat resistance of such a ventilation duct (200) is improved because the heat transfer between the first flange (200a) and the second flange (200c) is reduced by the intermediate layer (201) made of composite material. Figure to be published with the abstract: Fig. 2

Description

Title of the invention: Hybrid heat-resistant ventilation duct for aircraft. technical field

[0001] This disclosure relates to ventilation ducts adapted to supply and / or exhaust air from various systems located in fire hazard areas of an aircraft. STATE OF PRIOR ART

[0002] Aircraft are known to include ventilation ducts adapted to supply and / or exhaust air from various aircraft systems, such as an engine pre-cooling system, located in areas of the aircraft at risk of fire. These ventilation ducts are positioned at the boundary of these areas at risk of fire.

[0003] By "fire hazard zone" is meant an area of ​​the aircraft in which there is a high risk of fire due to the presence of an aircraft component that could be a source of fire (e.g., engine, fuel tank...).

[0004] Fig. 1 schematically illustrates a longitudinal view of a ventilation duct 100 according to the prior art.

[0005] The ventilation duct 100 is adapted to supply and / or exhaust air from an inlet and / or outlet of a first duct 101, for example, from an aircraft engine pre-cooling system, and located in a fire hazard zone ZF. The ventilation duct is located partly within the fire hazard zone ZF and partly outside, in an area ZA adjacent to said fire hazard zone (also referred to hereafter as the "adjacent area ZA"). A fire-resistant thermal blanket 103, known from the prior art, separates the two areas ZF and ZA. Such a fire-resistant thermal blanket 103 is, for example, a very thin steel film that encapsulates insulation such as ceramic, glass, or rock fibers.

[0006] The ventilation duct 100 comprises a flange 100a located inside the fire hazard zone ZF and a duct, also hereafter referred to as the second duct 100b, located in the adjacent zone ZA. The first duct 101 is fitted with a gasket 102 which bears against the flange 100a which, by means of one or more fastening means (not shown), such as bolts, secures the fire-resistant thermal blanket 103.

[0007] In this example, the flange 100a and the second duct 100b form a ventilation duct 100 made of a single block of the same heat-resistant material, such as a titanium or steel alloy. Such a 100mm ventilation duct is heavy and / or expensive to manufacture.

[0008] It is therefore desirable to overcome this drawback of the prior art. In particular, it is desirable to provide a solution that makes it possible to lighten the duct while limiting heat transfer along the ventilation duct. Description of the invention

[0009] An aircraft is proposed here comprising a fire hazard zone through which a first duct of an aircraft system passes, and a zone adjacent to said fire hazard zone and separated from said fire hazard zone by a fire-resistant thermal blanket having a through-window opposite which the first duct opens. The aircraft comprises: a ventilation duct for supplying and / or exhausting air from the first duct. This ventilation duct comprises a first flange located in the fire hazard zone, and a second duct with a second flange located in the adjacent zone. The first and second flanges are arranged opposite the window to ensure fluid continuity between the first and second ducts.The ventilation duct further comprises an intermediate layer made of a composite material and located between the first flange and the second flange, and fastening means which fix the first and second flanges to the intermediate layer.

[0010] Advantageously, the heat resistance of ventilation ducts can be improved by reducing heat transfer between the first flange located in the fire hazard zone and the second flange located in the adjacent zone. More specifically, by reducing this heat transfer in the event of a fire, it is possible to limit the deformation or degradation of the second flange, particularly when the latter is made of a material less heat-resistant than that constituting the first flange of the ventilation duct.

[0011] According to one embodiment, the fire-resistant thermal cover is attached to the first flange of the ventilation duct using fastening means.

[0012] According to one embodiment, the fastening means are titanium or steel bolts.

[0013] A method for manufacturing an aircraft as described above is also proposed herein. The method comprises: a step of supplying an aircraft including a fire hazard zone through which a first duct of an aircraft system passes, and a zone adjacent to said fire hazard zone and separated from said fire hazard zone by a fire-resistant thermal blanket having a through-window opposite which the first duct opens; a step of supplying a ventilation duct including a first flange, a second conduit with a second flange and an intermediate layer made of a composite material. This method further comprises: a step of assembling the first flange and the second flange with the intermediate layer between said first flange and said second flange, and - a step of fixing said first flange, said intermediate layer and said second flange together, using fixing means.

[0014] According to one embodiment, the process further includes a polymerization step, between the assembly step and the fixing step, when the composite material constituting the intermediate layer comprises an epoxy, phenolic or polyester resin. Brief description of the drawings

[0015] The features of the invention mentioned above, as well as others, will become clearer upon reading the following description of at least one exemplary embodiment, said description being made in relation to the accompanying drawings, among which:

[0016] [Fig-1] schematically illustrates a longitudinal view of a ventilation duct of the state of the art; and

[0017] [Fig.2] schematically illustrates a longitudinal view of a ventilation duct according to the invention;

[0018] [Fig.3] schematically illustrates, in side view, an aircraft comprising a ventilation duct according to the invention

[0019] DETAILED DESCRIPTION OF IMPROVEMENTS

[0020] Figure 2 schematically illustrates a longitudinal view of a ventilation duct 200 according to the invention adapted for supplying and / or exhausting air from various systems of an aircraft. Elements common to the invention and the prior art bear the same reference numerals, such as the first duct 101 and the fire-resistant thermal cover 103.

[0021] The ventilation duct 200 is a so-called hybrid ventilation duct adapted to supply and / or exhaust air from a first duct 101 of a pre-cooling system of an aircraft engine and located in the fire risk zone ZF separated from the adjacent zone ZA by the fire-resistant thermal cover 103. The first duct 101 opens opposite a window F through the fire-resistant thermal cover 103.

[0022] The ventilation duct 200 includes a first flange 200a of the flat flange type (also called a free flange) located inside the fire hazard zone ZF and opposite the window F. The ventilation duct 200 includes a second duct 200b comprising a flange, also called the second flange 200c. The second Flange 200c and the second duct 200a form a single block of the same heat-resistant material and are located in the adjacent zone ZA. The second flange 200c is positioned opposite window F to ensure fluid continuity between the first duct 101 and the second duct 200b of the ventilation duct 200.

[0023] The first conduit 101 is mounted with a seal 102 which comes to rest against the first flange 200a of the ventilation conduit 200.

[0024] In the embodiment of the invention presented here, the first flange 200a holds the fire-resistant thermal cover 103 using one or more fastening means (not shown), such as bolts.

[0025] The first flange 200a is made of a first heat-resistant material, for example titanium or steel. The second flange 200c and the second duct 200b form a single block of a second heat-resistant material, for example aluminum. The separation of the first flange 200a and the second duct 200b, which includes the second flange 200c, allows the use of different materials better suited to different environments in terms of cost and weight, and thus makes it possible to lighten the ventilation duct 200.

[0026] Furthermore, it is possible to foresee that the heat resistance threshold of the first material is higher than the heat resistance threshold of the second material. Indeed, since the first flange 200a is located within the fire hazard zone ZF, the material constituting it (i.e., the first material) must have a higher heat resistance threshold than the material (i.e., the second material) constituting the second flange 200c and the second conduit 200b, which are located in the adjacent zone ZA.

[0027] According to the invention, the ventilation duct 200 further comprises an intermediate layer 201 forming a perforated washer allowing fluidic continuity between the first duct 101 and the ventilation duct 200, and more particularly the second duct 200b. This intermediate layer 201 is located between the first flange 200a and the second flange 200c, with its opening opposite the window F

[0028] This intermediate layer 201 is made of a composite material that reduces heat transfer between the first flange 200a and the second flange 200c in the event of a fire. This improves the heat resistance of the ventilation duct 200 in the event of a fire by limiting the deformation or destruction of the second flange 200c, which is made of a heat-resistant material with a lower heat resistance threshold than the material constituting the first flange 200a.

[0029] According to one embodiment, this composite material is a carbon fiber reinforced polymer or CFRP (Carbon Fiber Reinforced Polymer). Alternatively, this composite material is a glass fiber reinforced polymer or GRFP (Glass Fiber Reinforced Polymer).

[0030] According to one embodiment, the polymer is for example a resin such as an epoxy, phenolic or polyester resin.

[0031] In one embodiment, the first flange 200a, the second flange 200c, and the intermediate layer 201 made of composite material are assembled upstream of the attachment to the first conduit 101. Once assembled, the resin is polymerized (e.g., by drying, autoclave, etc.). The first flange 200a, the second flange 200c, and the intermediate layer 201 are then fastened together using fastening means that clamp the intermediate layer 201 between the flanges 200a and 200c. Such fastening means are, for example, bolts, for example, made of titanium or steel.

[0032] Thus, in the event of a fire, even if the polymer (e.g. resin) of the intermediate layer 201 degrades, the fibers (e.g., carbon fibers or glass fibers) remain to ensure the thermal barrier between the first flange 200a and the second flange 200c.

[0033] The ventilation duct 200 according to this disclosure is simple to manufacture and implement and is inexpensive.

[0034] Fig. 3 schematically illustrates, in side view, an aircraft equipped with the ventilation duct 200 according to the invention.

Claims

Demands

1. Aircraft (300) comprising a fire hazard zone (FH) through which runs a first duct (101) of an aircraft system (300), and an adjacent zone (AZ) to said fire hazard zone (FH) and separated from said fire hazard zone (FH) by a fire-resistant thermal blanket (103) having a through window (F) opposite which opens the first duct (101), said aircraft comprising: a ventilation duct (200) for supplying and / or exhausting air from the first duct (101), said ventilation duct (200) comprising a first flange (200a) located in the fire hazard zone (FH), a second duct (200b) with a second flange (200c) and located in the adjacent zone (AZ), said first and second flanges (200a, 200c) being arranged opposite the window (F) to ensure fluidic continuity between the first conduit (101) and the second conduit (200b),an intermediate layer (201) made of a composite material and located between said first flange (200a) and said second flange (200c) and fastening means that fix said first and second flanges (200b, 200c) to the intermediate layer (201).

2. Aircraft according to claim 1, characterized in that the fire-resistant thermal cover (103) is attached to the first flange (200a) of the ventilation duct (200) using fastening means.

3. Aircraft according to any one of claims 1 to 2, characterized in that the fastening means are titanium or steel bolts.

4. A method for manufacturing an aircraft (300) according to claims 1 to 3, said method comprising a step of supplying an aircraft (300) comprising a fire hazard zone (FH) through which a first duct (101) of a system of the aircraft (300) passes, and an area adjacent (AH) to said fire hazard zone (FH) and separated from said fire hazard zone (FH) by a fire-resistant thermal blanket (103) having a through window (F) opposite which the first duct (101) opens, a step of supplying a ventilation duct (200) comprising a first flange (200a), a second duct (200b) with a second flange (200c) and an intermediate layer (201) made of a composite material, a step of assembling the first flange (200a) and the second flange (200c) with the intermediate layer (201) between said first flange (200a) and said second flange (200c), and a step of fixing said first flange (200a), said intermediate layer (201) and said second flange (200c), together, using fixing means.

5. A manufacturing method according to claim 4, characterized in that it further comprises a polymerization step, between the assembly step and the fixing step, when the composite material constituting the intermediate layer (201) comprises an epoxy, phenolic or polyester resin.

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