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
  • F04D29/26—Rotors specially for elastic fluids
  • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
  • F04D29/38—Blades
  • F04D29/384—Blades characterised by form
  • F04D29/386—Skewed 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
  • F04D29/26—Rotors specially for elastic fluids
  • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
  • F04D29/38—Blades
  • F04D29/384—Blades characterised by form
• • 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
  • F05D2240/20—Rotors
  • F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
  • F05D2240/301—Cross-sectional characteristics
• • 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
  • F05D2240/20—Rotors
  • F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
  • F05D2240/304—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the trailing edge of a rotor blade
• • 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 invention relates to fan propellers.
• a fan propeller comprising a hub and blades extending radially outwardly from the hub, in which each blade has a general profile, in particular an airplane wing, with a leading edge and a trailing edge, a neutral fiber and a rope between the leading edge and the trailing edge.
• a propeller may be used in particular in motor vehicle equipment, for example in a motor-fan unit to accelerate an air flow through a cooling module comprising one or more heat exchangers, including the cooling radiator of the vehicle engine.
• the propeller is then fixed on a shaft of an electric motor to be rotated.
• the blades of the propeller extend from the hub and their outer ends are free or joined by a profiled ring, also called “ferrule”.
• the propeller In the particular application to a motor vehicle fan unit, the propeller must operate under a wide range of conditions and must be able to produce a high airflow with a very low energy requirement. To satisfy such conditions, the propellers are conventionally equipped with a small number of blades (typically between 5 and 9), each blade having a rope of limited length to reduce the fan torque.
• the fan propellers low strength have the disadvantage of being very sensitive to operating conditions, the proximity of other mechanical components and air recirculation phenomena at the ends of the blades. Under adverse conditions, the overall efficiency drops leading to poor cooling conditions and / or higher energy requirements to drive the fan to a sufficient rotational speed.
• the blades of the propeller always have a classic profile in aircraft wing, in which the neutral fiber of the profile has a concavity of the same direction.
• the object of the invention is in particular to overcome the aforementioned drawbacks.
• the invention proposes, in a first embodiment of the invention, that the blade has, over at least part of its length, a flattened S shaped profile such that the neutral fiber has a point d and has two opposite concavities, namely a positive concavity between the leading edge and the inflection point and a negative concavity between the inflection point and the trailing edge.
• each of the blades is characterized by a specific conformation of the profile, over at least part of its length, which makes it possible to maintain the solidity at a suitable value without considerably increasing the drag and consequently the fan torque.
• This particular aerodynamic profile comes from the fact that the neutral fiber thereof has a point of inflection, which makes it possible to define two successive curvatures of opposite respective directions.
• the inflection point is advantageously located between 20% and 80% of the length of the rope from the leading edge.
• the inflection point be located closer to the trailing edge than the leading edge.
• the tangent to the neutral fiber at the point of inflection intersects the rope at a minimum angle of 4 °, preferably 10 to 20 °.
• the positive concavity of the profile has a camber of at least 2% and the negative concavity of the profile has a camber of at least 2%, the camber being defined as the ratio between the height of the neutral fiber relative to the rope and the length of the rope.
• the blade has on at least part of its length a shaped profile such that the neutral fiber has a positive concavity between the leading edge and an intermediate point and a generally flat portion between this intermediate point and the trailing edge.
• the tangent to the neutral fiber especially in the region of the intermediate point, intersects the cord at an angle of at least 4 °, said angle being considered at the point where the angle between the tangent to the neutral line and the rope is maximal.
• the intermediate point substantially corresponds to a point of inflection of the neutral fiber.
• the generally flat portion preferably has a length of between 20% and 60% of the length of the rope.
• the shaped profile according to the first or second embodiment of the invention is not necessarily present over the entire length of the blade, from its root at the hub to its outer end.
• the blade has an evolutionary profile which starts from said shaped profile in the region of the root at the hub and leads to an aircraft wing profile, without a point of inflection of the neutral fiber, in the end region of the blade.
• the fan impeller has a strength which is at least 0.5.
• the strength decreases from the root of the blades at the hub towards the end of the blades.
• the strength varies from about 0.9 to about 0.5 from the root of the blades to the end of the blades.
• FIG. 1 is a perspective view of a fan propeller according to the invention
• Figure 2 shows a developed cross section of a blade according to a first embodiment of the invention
• FIG. 3 is an enlarged detail of the blade of FIG. 2 in the region of the leading edge
• FIG. 4 is an enlarged detail of the blade of FIG. 2 in the region of the trailing edge
• FIG. 5 shows a flattened cross section of another blade according to the first embodiment of the invention, showing the respective camber of the positive concavity and the negative concavity of the profile
• - Figure 6 shows a developed cross section of a blade according to a second embodiment of the invention
• FIG. 7 is a partial perspective view of a fan propeller similar to that of FIG. 1, showing three cylindrical cups of a blade, respectively in a region close to the hub, in an intermediate region and in a region close to the helix ring
• FIGS. 8A, 8B and 8C respectively show the flattened cross-sections of the blade profile in correspondence of the three sections of FIG. 7
• Figure 9 shows schematically an air flow diagram between two blades of a propeller of the prior art
• FIG. 10 schematically shows an air flow diagram between two blades of a helix according to the invention.
• FIG. 1 shows a propeller 10 according to the invention intended to be part, in the example, a motorcycle fan unit of a motor vehicle.
• This helix is advantageously made in one piece by molding a suitable plastic material, for example a polyamide loaded with fibers or glass beads.
• the propeller 10 comprises a hub 12, also called “bowl”, adapted to be keyed on a motor shaft (not shown) of an electric motor to be rotated about an axis XX in a given direction of rotation. From the hub 12 extend radially a plurality of blades 14, in the example to the number of seven.
• blades have an inner end 16 (also called “root” or “foot”) which is attached to the hub 12 and an outer end 18 which is here connected to an outer ring 20 (also called “ferrule”).
• outer ends 18 of the blades may be free. Between the ends 16 and 18 extends an intermediate region 22.
• FIG. 2 shows the flattened cross-section of a blade 14, that is to say the plane closed curve obtained by cutting the blade by a cylindrical surface of revolution about the axis XX of the propeller, and unrolling this cylindrical surface flat.
• the blade 14 has a shaped profile having the shape of a flattened S. This profile is delimited by an inner line 24 of curved shape and an outer line 26 of curved shape, these two lines joining in a leading edge 28 and a trailing edge 30.
• the shaped profile here adopts a characteristic shape with a neutral fiber 32 which has a point of inflection 34.
• the neutral fiber corresponds to a mean line which, as a first approximation, is located halfway from the inner line 24 and the outer line 26 which delimit the profile. Due to this point of inflection, the neutral fiber 32 has a curvature or concavity inversion. It thus has two opposite concavities, namely a positive concavity C 1 between the leading edge 28 and the point of inflection 34 and a negative concavity C 2 between the point of inflection 34 and the trailing edge 30.
• the fiber Neutral 32 thus extends on both sides of the rope 36 which connects the leading edge 28 and the trailing edge 30.
• the point of inflection 34 is between 20% and 80% of the length L of the rope from the leading edge.
• the domain D on which the point of inflection 34 is located is materialized by a In general, it is preferred that the inflection point 34 be located closer to the trailing edge 30 than the leading edge 28, as is the case in FIG.
• this angle A will be between 10 and 20 °. The higher this angle, the more the concavities C x and / or C 2 will be pronounced.
• the positive concavity C 1 of the profile has a camber of at least 2%, the camber being defined as the ratio between the height H 1 of the neutral fiber 32 with respect to the cord 36 and the length L of the cord (FIG. ).
• This camber can for example be between 4 and 8%.
• the negative concavity C 2 of the profile has a camber of at least 2%, the camber being defined as the ratio between the height H 2 of the neutral fiber 32 with respect to the cord 36 and the length L of the cord ( Figure 4).
• This camber can for example be between 4 and 8%.
• H 1 is greater than H 2 , which results in the camber of the concavity C 1 is higher than the camber of the concavity C 2 .
• Figure 5 shows another profile of a blade similar to that of Figure 2 where the heights H 1 and H 2 and the angle A are indicated.
• FIG. 6 represents the flattened transverse section of a blade 14 according to a second embodiment of the invention which shows another blade profile which is similar to that of the first embodiment. supra.
• the blade has on at least part of its length a shaped profile such that the neutral fiber 32 has a positive concavity C 1 between the leading edge 28 and an intermediate point 38 and a generally flat portion P between this intermediate point 38 and the trailing edge 30.
• the tangent T to the neutral fiber in the intermediate point region 38 intersects the cord 36 at an angle B of at least 4 °.
• This angle B is considered where the angle between the tangent to the neutral line and the rope is maximal. It is preferably between 10 and 20 °, for example 8 ° and 12 °.
• the intermediate point 38 substantially corresponds to a point of inflection of the neutral fiber 32, located at the junction of the positive concavity C 1 and the generally flat portion P.
• the generally flat portion P has a length 1 generally between 10 and 80%, in particular between 20% and 60%, of the length L of the cord 36. In the example of FIG. 6, the length 1 corresponds substantially to a third of the length L.
• the intermediate point 38 is thus located in the example, closer to the trailing edge 30 than the leading edge 28.
• the shaped profile according to the first or second embodiment of the invention may be present over the entire length of the blade, or only a part of this length.
• the blade has an evolutionary conformal profile from the region of the root of the blade at the hub to the end region of the blade.
• FIG. 7 is a partial view of a helix of which one of the blades is cut in three places by cylindrical sections VIIIA, VIIIB and VIIIC, respectively in the region of the root near the hub, in an intermediate region and in a region near the outer end near the ring.
• Figs. 8A, 8B and 8C are the corresponding expanded cross-sections. They show the variations of the profile from the region of the inner end 16 (root) to the region of the outer end 18, passing through the intermediate region 22 ( Figure 5B). It can be seen that the profile is much more arched in the root region ( Figure 8A) than in the outer region ( Figure 8C) through a transition ( Figure 8B).
• blade profiles are possible as long as the shaped profile (in the S-flattened example) is present on at least a part of the length of the blade.
• the profile can progressively change from a specific form according to the first or second embodiment of the invention to a conventional plane wing shape, without inversion of curvature and without point of inflection.
• the positive concavity is prolonged by a negative concavity
• the positive concavity is prolonged by a generally flat portion.
• the positive concavity has an extension (negative concavity or generally flat part) which extends to the trailing edge and which influences the flow of the fluid set in motion by the propeller.
• FIG. 10 shows that, because of the shaped profile of the invention (in the flattened S-shaped example), the air flow lines F 1 remain attached, without separating or creating turbulence as in FIG. The case of Figure 9. These lines are thus guided and clamped between the blades 14. The same result can be obtained with a shaped profile according to the second embodiment of the invention.
• the strength is preferably at least 0.5 and may vary from about 0.9 to about 0.5 from the root of the blades to the end of the blades. As a comparison, for a conventional blade, this strength varies from about 0.7 at the root to 0.3 at the end. Thus, with a higher strength, but with a shaped profile according to the first or second embodiment of the invention, better performance without generating turbulence or other disturbances, and without requiring a higher torque.
• the invention finds a preferential application to motorcycle fan units of motor vehicles.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (2)

Family

ID=42371499

Family Applications (1)

Country Status (8)

Cited By (2)

Families Citing this family (20)

Family Cites Families (12)

• 2009
  • 2009-12-07 FR FR0905893A patent/FR2953571B1/fr not_active Expired - Fee Related
• 2010
  • 2010-11-08 PL PL10773918T patent/PL2510243T3/pl unknown
  • 2010-11-08 JP JP2012542424A patent/JP6022941B2/ja not_active Expired - Fee Related
  • 2010-11-08 US US13/514,153 patent/US9353764B2/en active Active
  • 2010-11-08 CN CN201080063289.1A patent/CN102753835B/zh active Active
  • 2010-11-08 IN IN5065DEN2012 patent/IN2012DN05065A/en unknown
  • 2010-11-08 EP EP10773918.7A patent/EP2510243B1/fr active Active
  • 2010-11-08 WO PCT/EP2010/067007 patent/WO2011069762A2/fr not_active Ceased

Non-Patent Citations (1)

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