Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/40—Casings; Connections of working fluid
  • F04D29/52—Casings; Connections of working fluid for axial pumps
  • F04D29/54—Fluid-guiding means, e.g. diffusers
  • F04D29/541—Specially adapted for elastic fluid pumps
  • F04D29/542—Bladed diffusers
  • F04D29/544—Blade shapes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/14—Form or construction
  • F01D5/141—Shape, i.e. outer, aerodynamic form
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D9/00—Stators
  • F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
  • F01D9/04—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector
  • F01D9/041—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector using blades
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
  • F04D29/661—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for elastic fluid pumps
  • F04D29/663—Sound attenuation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2220/00—Application
  • F05D2220/30—Application in turbines
  • F05D2220/32—Application in turbines in gas turbines
  • F05D2220/323—Application in turbines in gas turbines for aircraft propulsion, e.g. jet engines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2240/00—Components
  • F05D2240/10—Stators
  • F05D2240/12—Fluid guiding means, e.g. vanes
  • F05D2240/125—Fluid guiding means, e.g. vanes related to the tip of a stator vane
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2250/00—Geometry
  • F05D2250/30—Arrangement of components
  • F05D2250/38—Arrangement of components angled, e.g. sweep angle

Definitions

• TURBOMACHINE BLOWER RECTIFIER DRAWER TURBOMACHINE ASSEMBLY COMPRISING SUCH A BLADE AND TURBOMACHINE EQUIPPED WITH SAID DAUTHOR OR SUCH ASSEMBLY.
• the present invention relates to the field of turbomachines. It is aimed at a turbomachine blade and in particular a fan straightener blade.
• the invention also relates to an assembly comprising a nacelle and a fan casing secured to the nacelle and which is equipped with at least one stator blade and a turbine engine equipped with such a blade or such an assembly with a blade of rectifier.
• the natural evolution of multi-stream turbofan engines having a blower, in particular upstream, is to increase the propulsive efficiency via a reduction in the specific thrust obtained by decreasing the compression ratio of the blower, which results in an increase in the or BPR (Bypass Ratio), which is the ratio of the mass flow rate of air through the vein (s) surrounding the gas generator to the mass flow of air through the generator of gas, calculated at maximum thrust when the engine is stationary in an international standard atmosphere at sea level.
• BPR Battery Ratio
• the increase in the dilution rate affects the diameter of the turbomachine which is constrained by a minimum ground clearance to be respected because of the integration of the turbomachine most often under the wing of an aircraft.
• the increase in the dilution rate takes place primarily on the diameter of the fan.
• the blower is enveloped by a blower housing that surrounds the blower vanes and is connected to the gas generator by stator vanes known as rectifiers or exit guide vanes for the English designation "Outlet Guide”.
• the deflection angle formed between two leading edge segments or two trailing edge segments forms an obtuse angle or sharp angle.
• the arrow angles of the leading and trailing edges form a sudden change of direction, so there is no curvature between two segments of the leading edge or the trailing edge.
• An example of a straightener blade illustrated in FIG. 8c of this document shows a lower blade portion with an angle inclination A which is completely opposite to that of the upper blade portion.
• the present invention is intended in particular to limit the drag of the turbine engine nacelle and to limit the mass of the assembly of propulsion while acting on the acoustic phenomena occurring in the vicinity of a stator blade.
• a turbomachine stator vane with a longitudinal axis, the vane comprising a plurality of blade sections stacked radially with respect to the longitudinal axis along the longitudinal axis.
• a stack line between a foot end and a head end, each blade section comprising a bottom surface and an extrados surface extending axially between an upstream leading edge and a trailing trailing edge and being tangentially opposed, between the leading and trailing edges of each blade section being formed a profile cord of substantially constant length between the leading end and the foot end, and the stacking line having a curvature in a plane passing substantially through the longitudinal axis and the stack line, located in the vicinity of the head end and oriented from downstream to upstream.
• the shape of the stator vane with this curvature makes it possible to shorten the length of the nacelle surrounding the fan casing intended to carry this stator vane, which advantageously reduces drag. It also reduces the noise generated towards the end of the blade head when the latter is mounted in the nacelle.
• the acoustic intensity increases with the proximity between the fan blades and the stator vanes. The zones located around 75% of the height of the blade are particularly concerned by these interactions because of the observed speeds and the aerodynamic load involved. The profile of the stator blade thus makes it possible to maintain a minimum axial distance. required to the top of the stator vanes.
• the curvature of the stacking line is continuous and progressive. Such a configuration reduces vortex formation which also generates noise. Indeed, a change abrupt would significantly affect the vortices that can form in the upper part of the dawn and is a source of noise.
• the curvature is situated between
• the shape of the blade is determined by the following relationship: 0.1 ⁇ (L 2 / L 1) 5 O% H ⁇ H ⁇ 95% H ⁇ 0.5, L2 corresponding to the minimum distance between the leading edge of the blade and a line passing through the foot end and the leading end of the blade, L1 corresponding to the length between this same line and the trailing edge of the stator dawn and H being the height of the dawn.
• This configuration makes it possible, on the one hand, to limit the maximum angle at the foot end of the blade and, on the other hand, to limit the structural constraints.
• the curvature of the straightener blade is set between 50% and 95% of its height.
• the blade has a first foot portion whose stacking line extends along a straight line and a second head portion whose stacking line comprises the curvature.
• the stack line extending along a straight line is inclined with respect to the longitudinal axis.
• the leading edge has a concave portion and the trailing edge has a convex portion at the curvature.
• the directions of the leading edge and trailing edge of the blade are substantially parallel to the direction of the stack line.
• the invention also relates to an assembly comprising a turbomachine boat nacelle extending along a longitudinal axis and a fan casing secured to the nacelle, the fan casing surrounding a fan and delimiting downstream of the fan an annular vein in which circulates a flow of air, the fan casing comprising an annular row of stator vanes having any of the above characteristics arranged downstream of the fan blades transversely in the annular vein.
• a turbomachine boat nacelle extending along a longitudinal axis and a fan casing secured to the nacelle, the fan casing surrounding a fan and delimiting downstream of the fan an annular vein in which circulates a flow of air, the fan casing comprising an annular row of stator vanes having any of the above characteristics arranged downstream of the fan blades transversely in the annular vein.
• EPNdB Effective Perceived Noise
• the nacelle has a length substantially along the longitudinal axis of between 3000 and 3800 mm.
• the nacelle has a length substantially along the longitudinal axis and the fan has a diameter, substantially along the radial axis, the ratio of the length of the nacelle to the diameter of the fan being between 1 and 3
• the diameter of the blower is measured at a leading edge at its fan blade head.
• the relative axial distance between a fan blade and a stator blade is determined by the following condition: (d / C) where d is the distance between a trailing edge of the fan and the leading edge of the fan. the stator vane, and C being the length of the axial cord of the fan blade, the curvature of the stacking line making it possible to verify the following relation: (d / C) SO% H ⁇ H ⁇ 95% H (d / C) 100% H, with H the height of the straightener blade between the head end and the foot end.
• (d / C) 50% H ⁇ H ⁇ 95% H is the distance between the trailing edge of the blower and the leading edge of the straightener blade divided by the length of the axial rope of the blade of blower between 50% and 95% of the height of the stator vane
• (d / C) 100% H is the distance between the trailing edge of the blower and the leading edge of the divided stator vane by the length of the axial cord of the dawn of blower at the head of the dawn of rectifier.
• 100% H corresponds to the blade height in contact between the stator vane and the fan casing.
• the invention also relates to an assembly comprising a turbomachine boat nacelle extending along a longitudinal axis and a fan casing secured to the nacelle, the fan casing surrounding a blower and defining downstream of the blower an annular vein in which circulates a flow of air, the nacelle comprising an annular row of stator vanes having any of the aforementioned characteristics arranged downstream of the fan blades transversely in the annular vein and a downstream end of the leading end of which is located downstream of a downstream end of the fan casing.
• EPNdB Effective Perceived Noise
• the invention also relates to a turbomachine comprising at least one stator blade having at least one of the above-mentioned characteristics.
• FIG. 1 schematically represents a turbomachine with a fan upstream of a gas generator and to which the invention applies;
• FIG. 2 schematically illustrates, in front view, a turbomachine blade according to the invention
• Figure 3 schematically shows a cross section of blade according to the invention
• Figures 4 and 5 are schematic views in axial and partial sections of a nacelle housing a turbomachine fan according to the invention
• FIG. 6 is a diagrammatic representation of a graph on which is illustrated the variation of the angles with respect to the longitudinal axis of the turbomachine measured at the trailing edge of the turbomachine blade;
• FIG. 7 schematically illustrates, in axial and partial section, another embodiment of the invention in which a nacelle surrounds a fan and at least one stator blade, the stator blade comprising a downstream end at the end of head immediately downstream of a downstream end of the fan casing;
• FIG. 8 is another schematic representation of a graph showing the angles measured at the trailing edge of turbomachine vanes and in particular the prior art with respect to the stator vane according to the invention.
• FIG. 1 illustrates a turbine engine 100 for an aircraft to which the invention applies.
• This turbomachine 100 is here a double-flow turbomachine which extends along a longitudinal axis X.
• the double-flow turbomachine generally comprises an external nacelle 101 surrounding a gas generator 102 upstream of which a fan 103 is mounted.
• Downstream are defined with respect to the flow of gas in the turbomachine 100.
• the terms “upper” and “lower” are defined with respect to a radial axis Z perpendicular to the axis X and with respect to the distance from to the longitudinal axis X.
• a transverse axis Y is also perpendicular to the longitudinal axis X and to the radial axis Z.
• the gas generator 102 comprises in this example, from upstream to downstream, a low pressure compressor 104, a high pressure compressor 105, a combustion chamber 106, a high pressure turbine 107 and a low pressure turbine 108.
• the gas generator 102 is housed in an inner casing 109.
• the fan 103 is here faired and is also housed in the nacelle 101.
• the turbomachine comprises a fan casing 56 which surrounds the fan.
• a retention casing 50 which surrounds the plurality of moving fan blades 51 which extend radially from the fan shaft mounted along the longitudinal axis X.
• the fan casing 56 and the Retention casing 50 are integral with the nacelle 101 which surrounds them.
• the nacelle 101 has a generally cylindrical shape.
• the fan casing 56 is located downstream of the retention casing 50 ensuring the retention of the fan blades 51.
• the fan 103 compresses the air entering the turbomachine 100 which is divided into a hot stream circulating in an annular primary stream V1 which passes through the gas generator 102 and a cold stream flowing in a secondary annular duct V2 around the gas generator 102
• the primary vein V1 and the secondary vein V2 are separated by an annular interveinal casing 1 placed between the nacelle 101 and the inner casing 109.
• the hot flow circulating in the primary vein V1 is conventionally compressed. by compressor stages before entering the combustion chamber.
• the combustion energy is recovered by turbine stages which drive the compressor stages and the fan.
• the latter is rotated by a power shaft of the turbomachine via, in the present example, a power transmission mechanism 57 to reduce the speed of rotation of the fan.
• the power transmission mechanism 57 comprises a gearbox, arranged here axially, between a fan shaft integral with the fan and the power shaft of the gas generator 102.
• the cold air flow F circulating in the secondary vein V2 is oriented along the longitudinal axis X and participates for its part to provide the thrust of the turbomachine 100.
• each fan blade 51 has a leading edge 52, upstream and a trailing edge 53, downstream axially opposed (along the longitudinal axis X).
• the fan blades 51 each have a foot 54 implanted in a hub 30 which is traversed by the fan shaft and a head 55 opposite the retention housing 50.
• the fan blades 51 have a diameter DF inclusive, for example, between 1700 and 2800 mm.
• the diameter DF is measured at the leading edge 52 and at the level of the fan blade head 51, along the radial axis Z.
• the diameter DF is between 1900 and 2700 mm.
• the nacelle 101 it has an outer diameter DN of between 2000 and 4000 mm, for example.
• the external diameter DN is between 2400 and 3400 mm.
• stator vane 1 or fixed radial known as the blade of the fan straightener or fan flow guide vane.
• the straightener blade is also known by the acronym OGV for "Outlet Guide Vane” in English and thus allows to straighten the cold flow generated by the fan 103.
• OGV Outlet Guide Vane
• this stator vane is distinct and contrary to a rotor blade or rotor of the
• a plurality of stator vanes 1 is arranged transversely in the fan nacelle 101 substantially in a plane transverse to the longitudinal axis X.
• the nacelle 101 then surrounds the stator vanes. To straighten the flow of the fan 103, between ten and fifty stator vanes 1 are distributed circumferentially to form a rectifier stage. These blades of rectifier 1 are arranged downstream of the fan 103. In the present example, they are secured to the fan casing 56. These are also regularly distributed around the axis X of the turbomachine.
• each stator vane 1 comprises a plurality of transverse blade sections 2 stacked in a radial direction (parallel to the radial axis Z) along a stack line L between one end 3 and a leading end 4.
• the stacking line L passes through the center of gravity of each blade section 2 transverse.
• Each blade section comprises an intrados surface 7 and an extrados surface 8 extending substantially in an axial direction, between a leading edge 5, upstream and a trailing edge 6, downstream.
• the intrados and extrados surfaces 7, 8 are opposed to each other in a tangential direction (parallel to the Y axis).
• Between the trailing edge 6 and the leading edge 5 extends a CA profile rope.
• the blade section 2 comprises a curved transverse profile.
• the CA profile cord has a length, axial, substantially constant between the foot end 3 and the head end 4. In other words, the length of the profile cord at the foot end is substantially equal to the length of the profile cord at the head end.
• the stacking line L of the blade sections 2 forming the blade has a curvature in the vicinity of the head end 4 thereof.
• the stator dawn 1 has here substantially a boomerang shape.
• the curvature is oriented from the downstream to the upstream (radially outward).
• the leading edge 5 and the trailing edge 6 follow the bending motion of the stacking line L. That is, the direction of the leading edge 5 and the trailing edge 6 are substantially parallel to the direction of the curvature of the stacking line L in the upper part of the blade 1.
• the curvature is continuous and progressive. That is, there is no abrupt change of direction.
• the curvature of the stacking line L is oriented in a perpendicular plane passing through the longitudinal axis X.
• the stacking line L is therefore defined in this plane.
• Curvature is also located towards the head end 4. This is situated between 50% and 95% of the height H of the blade 1 taken between the root end 3 and the head end 4 of the blade as described later in the description.
• Each stator vane 1 is fixed to the inner casing 1 10 and to the fan casing 56 secured to the nacelle 101.
• the stator vanes 1 provide a structural role, they allow the recovery of efforts.
• the foot end 3 is connected in this example to the inner casing 1 10 while the leading end 4 is connected to the fan casing 56.
• the leading edge 5 is concave while the trailing edge 6 is convex.
• the blade 1 has a first portion whose stacking line L is substantially straight. This so-called right stacking line is located in the lower part of the blade 1.
• the latter has a downward inclination, in a plane containing the longitudinal axis X, with respect to the axis X.
• the inclination forms an angle a between 105 ° and 145 ° between the stacking line L and the X axis (the stack line being downstream).
• a first portion of the trailing edge 6 extends along a line forming an angle ⁇ 1 with the longitudinal axis.
• This angle ⁇ 1 is between 90 ° and 120 °, the trailing edge 6 being oriented downstream.
• This angle ⁇ 1 varies from the longitudinal axis from upstream to downstream.
• the blade 1 also has a second portion where the stacking line L has the curvature or an elbow.
• the trailing edge 6 also has a curvature or bend on the second portion of the blade 1.
• the curvature of the trailing edge 6, in the upper part of the blade 1 is determined by an angle ⁇ 1 formed between a tangent line T at the trailing edge 6 and the longitudinal axis X.
• the angle ⁇ 1 varies in the upper part of blade 1.
• the upper part of the trailing edge with the curvature is located between 50% and 95% of the height H of the blade 1 starting from the foot end of the blade.
• the angle ⁇ 1 of curvature of the trailing edge 6 is between 75 ° and 90 °, the trailing edge being oriented upstream and the value of 90 ° is not included.
• the angle ⁇ 1 between the longitudinal axis and the trailing edge 6 is substantially constant between 0 and 50% of the height of the blade.
• the angle ⁇ 1 then varies between 50% and 95% of the height of the blade 1. We therefore understand that there is no right angle and therefore no abrupt change of direction of the trailing edge.
• Such a configuration makes it possible, on the one hand, to reduce the space requirement and, on the other hand, to maintain a predetermined minimum axial distance d close to the initial predetermined minimum axial distance of a conventional rectifier blade.
• the minimum axial distance is measured between the trailing edge 53 of the fan blade 51 and the leading edge 5 of the stator blade.
• the curved shape avoids accentuating the vortex phenomena in the vicinity of the dawn which are responsible for the noise.
• angles ⁇ 1 which the trailing edge 6 has with respect to the longitudinal axis are represented in a graph of FIG. 6 and FIG. 8 in comparison with angles of the trailing edge of the stator vanes of the state of the 'art.
• the angles of the trailing edge of the blades of the state of the art have an angle whose value is between 90 ° and 120 ° and is constant along the height of the blade (OGV10 and OGV12) , or whose value varies between 90 ° and 120 ° between 50% and 95% of the height of the blade (OGV1 1), or whose value is between 0 and 90 ° and is constant along the height of dawn (OGV13).
• OGV14 rectifier blade shown in Figure 8 which corresponds to the blade of the prior art US-B1 -6554564 which has an arrow angle in the middle part of the height of the blade.
• the value of the angle is constant over the first 50% of the height of the dawn from the foot end and also constant but completely opposite on the last 50% of the height of the dawn from the middle part towards the head end of the dawn.
• the stator blade of the present invention has an angle whose value is constant and between 90 ° and 120 °, between 0 and 50% of the height of the blade, and whose value varies between 75 ° and 90 ° between 50% and 95% of the height of the blade.
• the line representing the variation of the angle of the blade 1 is continuous. In others In other words, there is no break in continuity in the line representing the variation of the angle.
• the head end 4 of the stator vane 1 is connected to the fan casing 56 in a fixing zone further upstream of the zone of attachment of an AR stator vane. of the prior art shown in dashed line.
• the head end 4 of the blade of the present invention is shifted upstream due to the curvature.
• This offset and / or the curvature makes it possible to shorten the length, substantially along the longitudinal axis X, of the nacelle 101.
• the nacelle here has a length LN between 3000 and 3800 mm taken between an upstream end 20 forming an air inlet lip and a downstream end 21 forming a nozzle edge.
• the length LN is between 3100 and 3500 mm.
• the reduction gain of the length of the nacelle is, for example, between 5 and 15% compared to a standard turbomachine nacelle without the invention as shown in dashed lines in FIG. 4.
• the arrangement of the blade 1 according to the invention allows the reduction of the length of the nacelle 101 without aggravating the noise nuisance for the same given fan diameter.
• the gain in length makes it possible to reduce the aerodynamic drag of the turbomachine and / or the integration of larger areas of acoustic panels for equivalent drag, as described later in the invention.
• the acoustic gain is about 2 EPNdB ("Effective Perceived Noise” in English or "noise level actually perceived, in decibels").
• the ratio of the length of the nacelle to the diameter of the fan can be between -5% and -15% compared to a turbomachine without the invention, which implies a reduction in the length of the nacelle between -5% and -15% compared to a turbomachine without the invention.
• the ratio LN / DF is for example between 1 and 3.
• the ratio is between 2.1 and 2.8.
• the relative minimum axial distance between the fan blades and the stator vanes is determined by the relation d / C.
• d is the predetermined minimum axial distance between the trailing edge 53 of the fan and the leading edge 5 of the stator vane 1.
• C is the length of the axial chord of the blower. The axial rope C of the fan is measured between the leading edge 52 and the trailing edge 53 of the fan blade.
• H corresponds to the outer radius of the stator vane 1 taken between the foot end and the head end of the vane 1. In other words, between 50% and 95% of the height H of the blade, the relative minimum axial distance between the fan 103 and the stator blade 1 is greater than the relative minimum axial distance measured at the head end of the blade. dawn, that is to say for 100% of the height H of the stator vane 1.
• the parameter a corresponds to an efficiency factor.
• the parameter considered to be greater than 1 .1 is defined as a condition to guarantee the effectiveness of the invention.
• the parameter ⁇ is a parameter characterizing the condition ⁇ ⁇ 3 to constrain the length of the nacelle and maintain the desired performance advantage.
• H height
• d (r) the percentage of height of the blade 1 with 0% H (at the foot end of the blade 1) and 100% H (at the head end of the blade 1).
• acoustic treatment of the nacelle may include the provision of acoustic panels to further reduce noise. These acoustic panels are advantageously, but not exclusively, disposed on an inner face of the nacelle 101 downstream of the stator vanes 1.
• the shape of the blade 1 is characterized by the following relation:
• L2 corresponds to the minimum distance between the leading edge 5 of the stator blade 1 and the line A passing through the foot end and the leading end of the blade taken at the leading edge 5.
• L1 corresponds to the length between this same line A and the trailing edge 6 of the stator vane.
• the lower (0.1) and upper (0.5) terminals are determined so as to limit the maximum angle of inclination of the stack line L to the foot end 3 of the stator vane 1 while limiting the curvature of the line stacking.
• the blade 1 has the same characteristics as that shown in FIGS. 4 and 5.
• the elements described above are designated in the rest of the description by the same reference numerals.
• the nacelle envelops the dawn 1 and the blower.
• the downstream end of the head end of the blade 1 is located downstream of the downstream end of the fan casing to reduce the mass of the turbomachine.
• the nacelle is made of materials lighter than the fan case. We seek to limit the extension of the fan case to replace it with the nacelle.
• the equipment of the nacelle such as a thrust reverser can be integrated further upstream, and in particular closer to the fan which reduces the axial extension of the nacelle and the turbomachine.
• the downstream end of the head end 4 is located vis-à-vis the nacelle 101.

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• Engineering & Computer Science (AREA)
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• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
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• Structures Of Non-Positive Displacement Pumps (AREA)

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• 2017
  • 2017-08-28 FR FR1757896A patent/FR3070448B1/fr active Active
• 2018
  • 2018-08-28 US US16/642,150 patent/US11377958B2/en active Active
  • 2018-08-28 CN CN201880059958.4A patent/CN111108262B/zh active Active
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