Aircraft engine assembly with pylon thermal protection

Abstract

An aircraft engine assembly (1) comprising: a pylon (2) having an upper portion (2a) connected to an aircraft wing and a lower portion (2b) provided with connection elements designed to be fixedly connected to a turbofan engine (3); a nacelle (4) provided with internal thermal walls (5) defining an internal tubular compartment (6) that encloses the turbofan engine (3); a thermal separation device (7) interposed between the lower portion (2b) of the pylon (2) and the nacelle (4) and designed to reduce thermal transmission from the internal compartment (6) to the lower portion of pylon (2b) The thermal separation device comprises a single body (8) comprising a one-piece housing made of carbon fibre composite and extending along a direction (D) and which encloses a material (9) which is thermally insulating and which is also fire-resistant; the single body has a series of pass-through openings (10) designed to allow the passage of harnesses and tubes that extend from the lower portion of pylon (2b) and are connected to the turbofan engine (3).

Description

[0001] "Aircraft engine assembly with pylon thermal protection"

[0002] Cross-Reference to Related Applications

[0003] This Patent Application claims priority from Italian Patent Application No . 102025000005264 filed on March 14, 2025, the entire disclosure of which is incorporated herein by reference .

[0004] Technical Field of the Invention

[0005] The present invention relates to an aircraft engine assembly with pylon thermal protection.

[0006] State of the art.

[0007] An aircraft engine assembly comprises : a pylon having an upper portion connected to an aircraft wing and a lower portion provided with elements adapted to be fixedly connected to a turbofan engine; a nacelle provided with internal thermal walls defining an internal tubular engine compartment that encloses the turbofan engine; a thermal separation device interposed between a lower portion of the pylon and the nacelle and designed to reduce heat transmission from the internal compartment to the pylon.

[0008] The engine compartment is in fact very hot (200 - 400 °C) and usually classified as a fire risk zone, for this reason it is necessary to provide the aforementioned thermal separation device which is made, as a rule, from a series offlat metallic elements that are normally called "blankets" . The function of the blankets is to protect the pylon from the heat and from the working fluids of the engine that may leak into the engine compartment .

[0009] However, the use of a series of blankets is in any case related to a heat transmission from the engine compartment to the colder structure of the pylon as each blanket is provided with connection points .

[0010] There is therefore a need to provide an aircraft engine assembly in which the heat transfer from the engine compartment to the pylon is reduced.

[0011] Description of the known art

[0012] US 2015 / 175272 Al discloses a structural element for an aircraft comprising a portion of the primary structure of the attachment pylon. According to said document, the portion of the primary structure of the attachment pylon is at least partially covered by a protective assembly comprising a layer forming a firewall and a thermally insulating layer, wherein the thermally insulating layer is positioned between the layer forming a firewall and the portion of the primary structure of the attachment pylon.

[0013] US4767656 A discloses a load-bearing structure of composite material which has a plurality of layers of composite material which maintains its structural integrity at 1200 °F for at least five minutes . The preferred matrixmaterials are polyimide resins .

[0014] Solution to the problem

[0015] The aforementioned scope of protection is realised by the present invention in that it relates to an aircraft engine assembly as defined in claim 1.

[0016] Description of the drawings

[0017] The invention will be described with the following drawing which represents a non-limiting example, in which:

[0018] Figure 1 represents, in a perspective view, a nacelle in a closed position;

[0019] Figure 2 shows the nacelle in an open position;

[0020] Figure 3 represents an internal portion of the nacelle; and

[0021] Figure 4 represents in a perspective view a part of the engine assembly according to the present invention.

[0022] Description of the preferred embodiment

[0023] In figures 1, 2, and 3, element 1 indicates an engine assembly for an aircraft comprising:

[0024] a pylon 2 (of a known type) having an upper portion 2a connected to an aircraft wing and a lower portion 2b provided with connection elements (not shown) adapted to be fixedly connected to a turbofan engine 3 (the turbofan engine is shown in figure 2 ) ;

[0025] a nacelle 4 (the nacelle 4 is shown in a closed position in figure 1 and is shown in an open position in figure 2 )provided with internal thermal walls 5 defining an internal tubular compartment 6 ( figure 3) that encloses the turbofan engine 3;

[0026] a thermal separation device 7 interposed between the lower portion 2b of the pylon 2 and the nacelle 4 and adapted to reduce thermal transmission from the internal tubular compartment 6 to the lower portion of pylon 2b, thereby protecting the pylon.

[0027] According to the present invention, the thermal separation device 7 is a single body 8 and comprises a one-piece housing made of composite carbon fiber and extending along a direction D. The single body 8 made of composite carbon fiber is thermally insulating and is also fire-resistant . For example, the thermal conduction coefficient K of the single body is below 0.5 W / mK.

[0028] The one-piece housing internally encloses a material 9 which is thermally insulating, and which is also fire-resistant, for example ceramic material with incorporated carbon fibers .

[0029] For example, the thermal conduction coefficient K of the material 9 is below 0.05 W / mK.

[0030] It should also be noted that the single body 8 and the material 9 are both made of a material resistant to aggressive agents or fluids such as the fluid normally used in turbofan engines .The single body 8 has a series of pass-through openings 10 adapted to allow the passage of harnesses and tubes that extend from the lower portion of pylon 2b and are connected to the turbofan engine 3.

[0031] Connection devices having the same structure as the thermal separation device, i . e . including an external single body made of composite carbon fiber and an internal material 9 which is thermally insulating and which is also fire-resistant, are shaped so as to be housed in respective holes to realize a stable connection between the thermal separation device and the lower portion 2b of the pylon 2.

[0032] Typically, the single body 8 has a constant thickness, for example 1 cm.

[0033] According to the test carried out by the applicant, the thermal separation device provides good protection for the pylon (the following data relate to a body having a thickness of 1 cm) :

[0034] If the temperature of the internal compartment reaches approximately 300 °C, the face of the single body 8 in contact with the pylon reaches approximately 60 °C, if the temperature of the internal compartment reaches approximately 400 °C, the face of the single body 8 in contact with the pylon reaches approximately 80 °C and, if the temperature of the internal compartment is lower (approximately 200 °C) , the face of the single body 8 incontact with the pylon reaches approximately 50 °C .

[0035] Reference numerals

[0036] 1 engine assembly

[0037] 2 pylon

[0038] 3 turbofan engine

[0039] 4 nacelle

[0040] 5 internal thermal walls

[0041] 6 internal tubular compartment

[0042] 7 thermal separation device

[0043] 8 single body

[0044] D direction

[0045] 9 material

[0046] 10 pass-through openings

Claims

Claims1. An aircraft engine assembly ( 1 ) comprising:a pylon (2 ) having an upper portion (2a) connectable to a wing of the aircraft and a lower portion (2b) provided with connection elements adapted to be fixedly connected to a turbofan engine (3) ;a nacelle (4 ) provided with internal thermal walls (5) defining an internal tubular compartment ( 6) that is configured to enclose the turbofan engine (3) ;thermal separation means (7 ) interposed between the lower portion (2b) of the pylon (2 ) and the nacelle (4 ) and adapted to reduce thermal transmission from the internal compartment ( 6) to the lower portion of pylon (2b) ,the thermal separation means comprise a single body ( 8 ) comprising a one-piece housing made of composite carbon fiber and extending along a direction (D) ; the single body has a series of pass-through openings ( 10) adapted to allow the passage of harnesses and tubes that extend from the lower portion of pylon (2b) and are connected to the turbofan engine ( 3 ) ,characterised in that connection devices are provided having the same structure as the thermal separation device; said connection devices including an external single body made of composite carbon fiber and an internal material which is thermally insulating and which is also fire-resistant;the connection devices are shaped so as to be housed in respective holes to realize a stable connection between the thermal separation device and the lower portion (2b) of the pylon ( 2 ) .

2. - The engine assembly as claimed in claim 1, wherein the one-piece housing internally encloses a material ( 9) which is thermally insulating, and which is also fire-resistant .

3. - The engine assembly as claimed in claim 2, wherein the material is ceramic material with incorporated carbon fibers .

4. - The engine assembly as claimed in claim 2, wherein the thermal conduction coefficient K of the single body ( 8 ) is below 0.5 W / mK and the thermal conduction coefficient K of the material ( 9) is below 0.05 W / mK.

Images