Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02K—JET-PROPULSION PLANTS
  • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
  • F02K1/78—Other construction of jet pipes
  • F02K1/82—Jet pipe walls, e.g. liners
  • F02K1/822—Heat insulating structures or liners, cooling arrangements, e.g. post combustion liners; Infrared radiation suppressors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02K—JET-PROPULSION PLANTS
  • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
  • F02K1/78—Other construction of jet pipes
  • F02K1/82—Jet pipe walls, e.g. liners
  • F02K1/827—Sound absorbing structures or liners
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• the present invention relates, firstly, to a turbofan engine used in the field of aeronautics, and secondly, to a primary nozzle equipping such a turbojet engine.
• a turbojet engine comprising a motor housed completely in a tubular nacelle whose internal wall defines with the engine casing an annular passage in which flows a secondary flow delivered by a blower.
• This nacelle has an air inlet upstream of the engine, thrust reversal means in its middle section, and a common ejection nozzle primary flow and secondary flow whose output is located downstream of the engine.
• Means for cooling the common nozzle are provided, especially when the thrust reverser means are in the position during which the secondary flow is deflected outwards and towards the front of the nacelle, this flow no longer sweeping the wall external of said common nozzle.
• Such an arrangement ultimately allows to choose a less dense material to achieve the common nozzle.
• the primary nozzles usually employed are constituted by means of an outer wall and an inner wall respectively made of titanium and inconel, an alloy of Ni-Cr-Fe austenitic, because of the good performance in temperature and good intrinsic mechanical properties of these materials.
• the present invention aims to solve the problem mentioned above, and for this consists of a turbofan engine comprising a motor housed in a nacelle, said engine having a housing defining with the nacelle an annular passage in which can flow a secondary flow delivered by a blower located upstream of the engine, a primary nozzle being fixed to the casing downstream of the engine and having, on the one hand, an inner wall adapted to channel a main flow; heat delivered by the engine, and secondly, an outer wall in contact with the secondary flow, characterized in that acoustic attenuation means equip at least a portion of the inner wall, and in that the outer wall comprises means for cooling the inner wall.
• the presence of means for cooling the internal wall allows the use of lower density materials but less heat resistant to achieve the primary nozzle. This ultimately makes it possible to compensate for the additional mass resulting from the integration of the acoustic attenuation means into the internal wall.
• the means for cooling the inner wall comprise at least one cooling air withdrawal means.
• each means for withdrawing cooling air is produced using a scoop fitted into the outer wall and designed to take a flow of air from the secondary flow.
• the inner wall comprises a sheet provided with a cooling air distribution means along the inner wall.
• each cooling air sampling means is then brought to the level of the dispensing means, advantageously made in the form of a drilling pattern in the sheet, to then lick the surface of the inner wall, which ultimately protects the latter from the hot main flow delivered by the engine.
• the acoustic attenuation means equipping the inner wall are made in the form of a sandwich panel disposed downstream of the cooling air distribution means.
• the means for cooling the inner wall may comprise at least one channeling means arranged between a cooling air sampling means and a cooling air distribution means.
• the present invention also relates to a primary nozzle intended to be positioned downstream of a motor equipping an aircraft, characterized in that it comprises an outer wall provided with means for cooling an inner wall provided with acoustic attenuation means.
• the means for cooling the inner wall advantageously comprise at least one cooling air withdrawal means.
• the latter is preferably made using a scoop arranged in the outer wall and designed to take a flow of air from the secondary flow.
• the inner wall comprises a sheet provided with a cooling air distribution means located upstream of the acoustic attenuation means.
• the acoustic attenuation means equipping the inner wall are advantageously made in the form of a sandwich panel disposed downstream of the cooling air distribution means.
• the means for cooling the inner wall comprise at least one channeling means arranged between a cooling air sampling means and a cooling air distribution means.
• FIG. 1 is a diagrammatic sectional view of a turbojet engine equipped with a primary nozzle.
• Figure 2 is a partial schematic sectional view of a primary nozzle according to a first embodiment of the invention.
• Figure 3 is an enlarged partial view of the nozzle of Figure 2.
• Figure 4 is a front perspective view of a primary nozzle according to a second embodiment of the invention.
• Figure 5 is a side view of the nozzle of Figure 4.
• FIG. 6 is a cross-sectional view of the nozzle of FIG. 4.
• FIG. 7 is a perspective view of a scoop equipping the nozzle of FIG. 4.
• FIG. 8 is a view from above of the scoop of FIG. 7.
• FIG. 9 is a sectional view of the scoop of FIG. 7.
• a turbojet engine 1 as shown in FIG. 1, generally comprises a nacelle 2 surrounding a double-flow engine 3 comprising a combustion chamber 3b.
• this engine 3 By means of blades of a blower 3a in rotation, this engine 3 generates at the outlet of the nacelle 2 two air flows, namely a hot air flow 4 from the combustion chamber 3b, and a cold air flow 5, said secondary flow, which flows outside the engine between an inner wall 7 of the nacelle 2 and an outer wall of a cover 8 surrounding the engine 3.
• the air flow Hot 4 thus has a high temperature, located around 750 0 C, while the cold stream 5 has a much lower temperature, located at about 100 0 C.
• the primary nozzle 6 comprises an inner wall 9, swept by the hot air flow 4, and an outer wall 10 along which the cold air flow 5 flows.
• internal wall 9 and the outer wall 10 meet at the rear of the primary nozzle 6 and are connected to the front by a stiffener 11.
• the walls 9, 10, 11 thus define an interior space 12.
• the attachment of the primary nozzle 6 to the rear of the engine 3 is carried out by means of a fastening flange 13 extending the inner wall 9 and screwed to a fastening flange 14 of the engine 3.
• the outer wall 10 extends slightly upstream beyond the stiffener 11 and is terminated by an angle 15 not bonded to the stiffener 11 and formed of flexible strips intended to ensure the junction with the downstream end of the cover 8.
• the outer wall 10 is made under the form of a sheet in beta21 s in which are formed openings 16 for each receiving a bailer fixed by nuts 17.
• the openings 16 are made to be located at about 45 ° on either side of the point anchoring of the nacelle 2 and the engine 3.
• the beta21s is a titanium alloy commercially available under the name TIMETAL21S from TIMET. This material is particularly suitable for aeronautical construction because of its good mechanical properties and its low density, approximately equal to half the density of the inconel. The use of this material therefore allows a very significant mass gain.
• the fixing flanges 13, 14 and the stiffener 11 being directly exposed to the flow of hot air 4 at the outlet of the combustion chamber 3b, they are always made in inconel.
• inconel and beta21s are materials given solely by way of example as they are commonly used in this field, the device according to the invention being absolutely not limited to the use of these materials.
• the scoops are static scoops 20, so called because they do not exceed the aerodynamic flow lines of the cold air flow 5 along the outer wall 10 of the primary nozzle 6.
• a static scoop 20 comprises, on the one hand, a frame 21 defining an opening 22 and having two lateral lugs 23 intended to be traversed by the nuts 17 to fix the static scoop 20 to the wall 10, and on the other hand, a wall inclined 24 relative to the plane of the frame 21 and for directing the flow of cold air 5 penetrating into the static scoop 20.
• This inclined wall 24 is connected to the front of the 21, in the direction of the flow of the cold air stream 5, and is bordered by side walls 25. The length and inclination of this inclined wall 24 are of course adapted to capture and orient an adequate amount of cold air flow id 5
• the scoops are dynamic scoops 30.
• a scoop dynamic 30 differs from a scoop static 20 only in that it has a crown 31 covering a part downstream of the frame 21 and protruding aerodynamic lines. This top 31 has a ridge 32 profiled so as to block the flow of cold air 5 and guide it towards the opening 22.
• the choice between a static scoop 20 and a dynamic scoop 30 will be made according to the amount of cold air flow 5 they can capture and the need for pressurization of the interior space 12 of the primary nozzle 6.
• the inner wall 9 is also made from a sheet 40 in beta 21s, lighter than inconel but less resistant to high temperatures. However, as explained above, the inner wall 9 is intended to be in contact with the flow of hot air 4. It is therefore undesirable to expose it directly to the contact with the hot flow without providing a cooling system.
• the sheet 40 has, on the one hand, a ventilation zone 41 in which openings 42 are formed in a suitable drilling pattern. These openings form a cooling air distribution means.
• the sheet 40 also has an acoustic attenuation zone 43 situated downstream of the aeration zone 41 with respect to the direction of the hot air flow 4, comprising a acoustic sandwich panel 44 oriented towards the hot air flow 4.
• beta 21s The mass gain achieved by using beta 21s allows the establishment of this sandwich panel 44 which, if it had been made in inconel, would have too heavy the structure.
• the flow of hot air 4 flows, at the outlet of the combustion chamber 3b, inside the primary nozzle 6 along the bottom wall 9 while the cold air flow 5, after its passage passage between the inner wall 7 of the nacelle 2 and the outer wall of the cover 8, flows outside the primary nozzle 6 along the upper wall 10.
• the cold air flow 5 meets the static or dynamic scoops 30, according to the embodiment, and enters the interior space 12 which it increases the pressure.
• the flow of the hot air flow 4 creates a depression at the openings 42 of the ventilation zone 41 causing the escape of the cold air present in the interior space 12 to higher pressure. This is then driven along the bottom wall 9 and forms a layer of cold fluid between the latter and the flow of hot air 4.
• the piercing pattern formed by the openings 42 is designed in such a way that the cold air present in the interior space 12 escapes and flows as close as possible to the bottom wall 9.
• the interior space 12 which fulfills the role of channeling means between the static or dynamic scoops 30 and the openings 42.
• a specific channeling means such as a pipe making this connection.
• the volume of the channeling means being smaller, the pressurization will be easier and a static scoop 20 may be sufficient where a dynamic scoop 30 was needed.
• the described embodiments show the realization of a drilling pattern. It should be understood that it is also possible to provide other forms of openings, such as slots, or multiple openings each associated with a channeling means clean.
• the term drilling pattern must therefore be defined globally with respect to the distribution of all the cold air supplied at the level of the lower wall 9 and not individually with respect to a given pipe means.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=34947698

Family Applications (1)

Country Status (6)

Families Citing this family (18)

Family Cites Families (10)

• 2004
  • 2004-07-15 FR FR0407881A patent/FR2873167B1/fr not_active Expired - Fee Related
• 2005
  • 2005-05-17 RU RU2007104966/06A patent/RU2397350C2/ru not_active IP Right Cessation
  • 2005-05-17 WO PCT/FR2005/001221 patent/WO2006016017A1/fr active Application Filing
  • 2005-05-17 CA CA002564508A patent/CA2564508A1/fr not_active Abandoned
  • 2005-05-17 EP EP05773042A patent/EP1766219A1/fr not_active Withdrawn
  • 2005-05-17 US US11/630,032 patent/US7866141B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

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