EP2935870A1 - Pale de turbine - Google Patents

Pale de turbine

Info

Publication number
EP2935870A1
EP2935870A1 EP13811916.9A EP13811916A EP2935870A1 EP 2935870 A1 EP2935870 A1 EP 2935870A1 EP 13811916 A EP13811916 A EP 13811916A EP 2935870 A1 EP2935870 A1 EP 2935870A1
Authority
EP
European Patent Office
Prior art keywords
turbine
turbine blade
opening
blade according
root
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP13811916.9A
Other languages
German (de)
English (en)
Inventor
Luke MCEWEN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gurit UK Ltd
Original Assignee
Gurit UK Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gurit UK Ltd filed Critical Gurit UK Ltd
Publication of EP2935870A1 publication Critical patent/EP2935870A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B17/00—Other machines or engines
    • F03B17/06—Other machines or engines using liquid flow with predominantly kinetic energy conversion, e.g. of swinging-flap type, "run-of-river", "ultra-low head"
    • F03B17/061—Other machines or engines using liquid flow with predominantly kinetic energy conversion, e.g. of swinging-flap type, "run-of-river", "ultra-low head" with rotation axis substantially in flow direction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B3/00—Machines or engines of reaction type; Parts or details peculiar thereto
    • F03B3/12—Blades; Blade-carrying rotors
    • F03B3/121—Blades, their form or construction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03B—MACHINES OR ENGINES FOR LIQUIDS
    • F03B13/00—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates
    • F03B13/12—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy
    • F03B13/26—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using tide energy
    • F03B13/264—Adaptations of machines or engines for special use; Combinations of machines or engines with driving or driven apparatus; Power stations or aggregates characterised by using wave or tide energy using tide energy using the horizontal flow of water resulting from tide movement
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D1/00—Wind motors with rotation axis substantially parallel to the air flow entering the rotor 
    • F03D1/06—Rotors
    • F03D1/065—Rotors characterised by their construction elements
    • F03D1/0658—Arrangements for fixing wind-engaging parts to a hub
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2230/00—Manufacture
    • F05B2230/60—Assembly methods
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2280/00—Materials; Properties thereof
    • F05B2280/60—Properties or characteristics given to material by treatment or manufacturing
    • F05B2280/6003—Composites; e.g. fibre-reinforced
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/20—Hydro energy
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a turbine blade, such as a water turbine blade or a wind turbine blade.
  • the present invention also relates to a turbine such as a water turbine or a wind turbine incorporating such a blade.
  • the present invention particularly relates to a turbine blade for use in a tidal generator.
  • Wind and tidal turbine blades are typically of laminated composite material (for fatigue resistance), bolted to the turbine hub using steel bolts. A connection therefore needs to be made between the bolts and the composite blade. Tidal hubs are usually sealed, and hence there is no access inside the hub for tightening the nuts on the blade connecting bolts. Small wind turbines also have limited or no manual access due to the size of the hub.
  • each hub spindle includes an enlarged circumferential flange to which the blade root is affixed using T-bolts.
  • that structure exhibits the problem of poor hydrodynamics.
  • the spindle is susceptible to fatigue failure at the internal radius of the flange.
  • the blade root incorporates a radially outwardly directed circumferential flange, and studs are screwed into blind holes in a hub spindle. Nuts are fitted onto the outboard end of the studs.
  • This arrangement suffers from the problem that the flanges are not strong enough when fabricated from fibre reinforced resin matrix composite material due to through thickness tensile (Brazier) loads at the tight radius, and so the flange tends to be made in steel or spheroidal graphite iron (SGI), which then needs to be connected to the composite blade, typically by an adhesive joint.
  • the difference in stiffness between the composite material and steel/SGI can lead to the existence of stress concentrations in the adhesive joint.
  • the present invention aims at least partially to meet that need.
  • the present invention provides a turbine blade adapted for fitting to a turbine member, the turbine blade comprising a root mounting portion which mounts an end of the turbine blade to the turbine member and is composed of fibre reinforced resin composite material, the root mounting portion having an end mounting surface for mating with a complementary mounting surface of the turbine member, a plurality of elongate bores spaced around and extending inwardly from the end mounting surface of the blade, and a plurality of openings in the root mounting portion, each opening being located at an end, remote from the end mounting surface, of a respective one of the bores, each opening being elongated in a direction extending longitudinally along a longitudinal axis of the respective elongate bore.
  • the present invention further provides a turbine including a turbine blade according to the invention fitted to a turbine member by a fitting system, the end mounting surface mating with a complementary mounting surface of the turbine member.
  • the invention relates to the attachment of a blade root to the rest of the turbine, typically to a central hub of the rotor in the case of an axial-flow turbine.
  • the turbine may be a water turbine, for example a tidal turbine, or a wind turbine
  • the turbine blades incorporating the embodiments of the present invention may be used in any type of turbine which generates electrical power from flow of water or air relative to the turbine blade, which causes motion of the turbine blade which in rum drives an electrical generator, either directly or via a gearbox or hydraulic pump.
  • the water turbine is most typically disposed in the sea, but may be disposed in a river, or even a lake or other body of moving water.
  • the turbine is a tidal turbine which is adapted to cause electrical power generation from tidal motion, either on a rising sea tide or a reverse falling sea tide, with the turbine moving by water flow relative thereto in either of two opposite directions.
  • the turbine is typically an axial flow turbine, in which plural radial turbine blades are fixed to a rotatable hub which is caused to rotate about an axis by water or wind movement over the turbine blade surfaces.
  • Figure 1 is a schematic perspective side view, partly in phantom, of a blade root structure and fitting system for fitting a tidal turbine blade root end to a rotatable hub in accordance with a first embodiment of the present invention
  • Figure 2 is a schematic side view, partly in phantom, of a blade root structure and fitting system for fitting a tidal turbine blade root end to a rotatable hub in accordance with a second embodiment of the present invention
  • Figure 3 is a part-sectional schematic plan view of a blade root structure and fitting system for fitting a tidal turbine blade root end to a rotatable hub in accordance with a third embodiment of the present invention
  • Figure 4 is a schematic longitudinal cross-section through a blade root structure and fitting system for fitting a tidal turbine blade root end to a rotatable hub in accordance with a fourth embodiment of the present invention.
  • Figure 5 is a schematic longitudinal side view of a bolt-style tensioner for use in a modification of the previous embodiments of the present invention to provide a fifth embodiment of the present invention.
  • FIG. 1 there is shown part of a water-driven turbine, in particular a tidal turbine, in accordance with a first embodiment of the present invention.
  • the turbine may be a wind turbine.
  • the tidal turbine 2 includes a turbine blade 4 having a root end 5 comprising a root mounting portion fitted by a fitting system 6 to a turbine member in the form of a rotational hub 8. A portion of only one turbine blade 4 is shown, although plural turbine blades 4 are fitted annul arly around the rotational hub 8.
  • the turbine blade 4 is composed of fibre reinforced resin composite material, for example produced from prepreg or resin-infused plies.
  • the hub 8 is typically formed of a metal.
  • the turbine blade 4 and rotational hub 8 define opposite respective annular load bearing mounting surfaces 12, 14 which are complementary and engage in a mating relationship at an interface 16.
  • the load bearing mounting surfaces 12, 14 and interface 16 are generally substantially annular and may be continuous or discontinuous.
  • the fitting system 6 extends across the interface 16 to fix the turbine blade 4 to the rotational hub 8.
  • the fitting system 6 comprises an annular array of a plurality of mutually spaced threaded studs 18.
  • a first helically threaded end 20 of each stud 18 is threadably received in a respective blind helically threaded hole 21 in the rotational hub 8 which extends into the hub 8 from the load bearing surface 14 of the hub 8.
  • a hollow elongate bore 22 extends inwardly of the turbine blade 4 from the load bearing surface 12 of the turbine blade 4 and terminates in an opening 24 which is elongated in the axial direction of the stud 18 to receive the stud 18.
  • the opening 24 is oval or elliptical in shape, with the major axis being aligned along the blade axis and/or along the longitudinal axis of the elongate bore 22 and stud 18.
  • the edges of the opening 24 are curved, so as to avoid or minimise stress concentrations in the composite material of the blade 4.
  • the opening 24 includes a near end portion 26 having a shaped support surface 28, typically a part-cylindrical, for example a semi-cylindrical, surface, adjacent to and surrounding the hollow bore 22.
  • a bearing element 30 has a correspondingly shaped surface 32 which is shaped to mate complementarily with the shaped surface 28 of the end portion 26 of the opening 24.
  • the bearing element 30 includes a non-threaded bore 34 extending therethrough, coaxial with the hollow bore 22, which has a larger diameter than the stud 18. Therefore the stud 18 can freely slide in the bearing element 30.
  • the bearing element 30 includes an upper substantially planar surface 33 remote from the lower surface 32.
  • the bearing element 30 is typically part-cylindrical, for example semi-cylindrical, and most typically comprises a semi-cylindrical barrel bearing.
  • a nut 36 is threadably fitted to the second helically threaded end 38 of the stud 18.
  • the nut 36 comprises an end member of the helically threaded element in the form of the stud 18, bearing directly or indirectly against the opening 24.
  • the free end 38 of the stud 18 extends into the opening 24 and is spaced from a far end portion 42 of the opening 24.
  • a central portion 40 of the opening 24 has sufficient length in the axial direction of the stud 18 that the free end 38 of the stud 18 is spaced a sufficient distance, for example 10 to 50 mm, from the far end portion 42 of the opening 24 so that a nut tightening tool (not shown), such as a hexagonal socket and associated wrench, can be fitted into the opening 24 and over the free end 38 of the stud 18 to tighten the nut 36.
  • the elongated opening 24 has a width greater than the width of the nut 36.
  • the width of the openings 24 may leave only a narrow strip 44 of fibre-reinforced resin composite material between adjacent openings 24. A full blade bending load must be transmitted through these strips 44, and therefore minimising the width of the opening 24 is of paramount importance and drives the required thickness of the fibre-reinforced resin composite material at the root 5 of the blade 4.
  • each stud 18 is threaded into a respective one of the blind helically threaded holes 21.
  • the free end 38 of the stud 18 is passed through a respective one of the hollow bores 22 and the respective bearing element 30 and into the opening 24.
  • a nut 36 is threaded onto the end 38 and tightened to the required preset torque setting using a tool such as a socket torque wrench.
  • Each of the pairs of stud 18/nut 36 is fitted in this manner annularly around the blade root 5.
  • FIG. 2 there is shown a modification of the embodiment of Figure 1 in which like parts are identified with like reference numerals.
  • the nut 36 is replaced by a multi-jackbolt tensioner (MJT) 50.
  • the MJT 50 comprises a cylindrical helically threaded annular body 52 which has an internal helical thread (not shown) which is coupled with the helical thread 54 of the second helically threaded end 38 of the stud 18.
  • An annular array of tensioning bolts (jackbolts) 56 surrounds the stud 18 and each tensioning bolt 56 is threadably coupled with the body 52.
  • the tensioning bolts 56 are parallel with the stud 18.
  • Each tensioning bolt 56 has a head 58, for example a hexagonal head, located remote from the bearing element 30 and a free end 60 which bears directly or indirectly (for example using an intermediate washer, for example of hardened steel) against the outer surface 62 of the bearing element 30 or a washer 63 thereon.
  • a head 58 for example a hexagonal head
  • free end 60 which bears directly or indirectly (for example using an intermediate washer, for example of hardened steel) against the outer surface 62 of the bearing element 30 or a washer 63 thereon.
  • each stud 18 is threaded into a respective one of the blind helically threaded holes 21.
  • the free end 38 of the stud 18 is passed through a respective one of the hollow bores 22 and the respective bearing element 30 and into the opening 24.
  • the body 52 of the MJT 50 is threaded onto the free end 38 of the stud 18 until the body 52 contacts or is slightly spaced from the bearing element 30.
  • the tensioning bolts 56 are rotated so as to be urged downwardly against the bearing element 30. As the tensioning bolts 56 are rotated, they apply an upward force on the body 52 of the MJT 50 away from the bearing element 30, and thereby apply a tensioning force on the stud 18.
  • Each head 58 of the tensioning bolts 56 is tightened to the required preset torque setting using a tool such as a socket torque wrench.
  • Each of the stud 18/ MJT 50 pairs is fitted in this manner annularly around the blade root 5.
  • each tensioning bolt 56 requires a smaller torque wrench as compared to the torque wrench, or possibly a hydraulic tensioner, required to tighten the single nut 36.
  • the opening 24 extends inwardly from a radially outer surface 27 of the blade root 5 and terminates inwardly of a radially inner surface of the blade root 5 to define a rear wall 29 of the opening 24 on the radially inner side of the blade root 5.
  • the opening 24, or at least a part thereof, may extend wholly or only partly through the thickness of the blade root 64.
  • the width of the opening 24 on the radially outer side 65 of the blade root 64 is larger than on the radially inner side 66, and the opposed sides 68, 70 of the central portion 40 of the opening 24 are not parallel but rather are mutually inclined to form a substantially angular segment in cross-section.
  • the opposed sides 68, 70 may be radially oriented towards the blade axis or alternatively may be oriented so as to provide a more pronounced angular segment, with the opposed sides 68, 70 being oriented toward each other on the radially inner side 66 by an acute angle even greater than that provided by radially oriented sides 68, 70.
  • This provides a relatively large opening width L on the radially outer side 65 and a relatively small opening width 1 on the radially inner side 66.
  • a conventional T-bolt mounting configuration for a substantially circular blade root provides minimum composite material width at the inside face of the blade root.
  • the strength of the composite material between the holes, and correspondingly between the fittings of the fitting system is enhanced. This in turn increases blade strength, because the minimum width of the composite material is increased.
  • Such an angular segment structure for the cross-section of the opening 24 also provides, for a given area of composite material in a transverse cross-section through the root 64 orthogonal to the longitudinal direction of the blade, a wider opening 24 for torque wrench 72 access on the radially outer side 65 of the blade root 64 than if the opening 24 had a substantially rectangular cross-section.
  • This configuration permits the torque wrench 72 to have a wider arc of operation when tightening the tensioning bolts 56 of the MJT 50, and furthermore permits the tensioning bolts 56 on the radially inner side 66 of the root 64 to be effectively accessed by a torque wrench entering the opening 24 on the radially outer side 65 of the blade root 64.
  • the result is that the blade root 64 can be effectively fitted to the hub 8 using the MJTs 50 without requiring any access to the inside of the blade root 64.
  • FIG. 4 there is shown part of a water-driven turbine, in particular a tidal turbine, in accordance with a fourth embodiment of the present invention.
  • the turbine may be a wind turbine.
  • the tidal turbine 102 includes a turbine blade 104 having a root end 105 fitted by a fitting system 106 to a turbine member in the form of a rotational hub 108. A portion of only one turbine blade 104 is shown, although plural turbine blades 104 are fitted annularly around the rotational hub 108.
  • the turbine blade 104 is composed of fibre reinforced resin composite material, for example produced from prepreg or resin-infused plies.
  • the hub 108 is typically formed of a metal.
  • the turbine blade 104 and rotational hub 08 define opposite respective load bearing surfaces 1 12, 1 14 which engage at an interface 1 16.
  • the fitting system 106 extends across the interface 1 16 to fix the turbine blade 4 to the rotational hub 108.
  • the fitting system 106 comprises an annular array of a plurality of threaded studs 1 18, although only one stud 1 18 is illustrated in Figure 4.
  • a first helically threaded end 120 of each stud 1 18 is threadably received in a respective blind helically threaded hole 121 in the rotational hub 108 which extends into the hub 108 from the load bearing surface 1 14 of the hub 108.
  • a hollow bore 122 extends inwardly of the turbine blade 104 from the load bearing surface 1 12 of the turbine blade 104 and terminates in an opening 124 which is elongated in the axial direction of the stud 1 18 to receive the stud 1 18.
  • the opening 124 is an open-ended recess 123 in a radially outer surface 125 of the blade root 5, the recess 123 being oriented along the longitudinal axis of the respective elongate bore 122.
  • the opening/recess 124/123 has no material located above the hollow bore 122.
  • the recess 123 has been cut, for example, by a rotating milling cutter moving downwardly in a single direction towards the hollow bore 122, the milling cutter comprising a cutting cylinder having an axis orthogonal to the axis of the hollow bore 122.
  • the edges of the opening 124 are curved, so as to avoid or minimise stress concentrations in the composite material of the blade 4.
  • the opening 124 includes a near end portion 126 having a shaped surface 128, typically a part-cylindrical, for example a semi-cylindrical, surface, adjacent to the hollow bore 122.
  • a bearing element 130 has a correspondingly shaped surface 132 which is shaped to mate complementarily with the shaped surface 128 of the near end portion 126 of the opening 124.
  • the bearing element 130 includes a non-threaded bore 134 which has a larger diameter than the stud 1 18. Therefore the stud 1 18 can freely slide in the bearing element 130.
  • the bearing element 130 is typically part-cylindrical, for example semi-cylindrical, and most typically comprises a semi-cylindrical barrel bearing. In alternative embodiments, the bearing element 130 is planar and bears against a planar surface adjacent to and surrounding the hollow bore 122.
  • a MJT 150 or a nut (not illustrated), is threadably fitted to the second helically threaded end 138 of the stud 1 18.
  • the open-ended opening 124/recess 123 provides a number of advantages.
  • the open-ended opening 124 allows the MJT or nut freely to be applied onto, and removed from, the stud along the stud direction, as shown by the arrow in Figure 4, without any blocking or interference from an upper end of the opening.
  • the opening 124 is freely accessible on the radially outer side 125, allowing easier access for a torque wrench.
  • the width of the opening 124 can be made even narrower as compared to the opening 24 of the previous embodiments, increasing blade strength.
  • a MJT 150 is employed, this provides the advantage that the opening 124 can be made narrower, and so the composite material of the blade root 105 can be made thinner, between the outer side 125 and an inner side 127 and so less expensive.
  • the first helically threaded end 120 of the stud 1 18 may have an enlarged diameter as compared to the remainder of the stud 1 18 so that the stud portion which is threadably received in the blind helically threaded hole 121 in the rotational hub 108 has greater thread diameter. This in turn provides a greater thread load-bearing area which extends into the hub 108 from the load bearing surface 1 14 of the hub 108. This strengthens the stud 1 18 and increases the fatigue resistance of the stud fittings.
  • a modified bolt for use in any of the embodiments is illustrated in Figure 5.
  • the bolt 200 is a bolt-style tensioner rather than a stud plus nut-style tensioner as shown in Figures 1 to 4.
  • the bolt 200 has a fixed head 202 and a shaft 204 extending therefrom, with a radially enlarged threaded end 206 of the shaft 204.
  • the enlarged thread diameter increases fatigue resistance.
  • Tensioning bolts 208 in the head 202 extend through the head 202 aligned with the direction of the shaft 204 and have lower ends 210 which bear against a planar bearing 212 on or in an annular support 214 surrounding the shaft 204.
  • the bolt-style tensioner of Figure 5 provides a more compact tension element which can permit a smaller hole and opening in the blade root. Also, the helical thread on the outer end of the stud can be omitted, thereby increasing the fatigue life.
  • the load bearing surfaces 1 12, 1 14 of the turbine blade 104 and rotational hub 108 are inclined at an acute angle a, typically from 2 to 30°, more typically from 5 to 10°, to the plane P which is transverse to the longitudinal axis of the blade root 105.
  • the interface 1 16 is similarly inclined, and is oriented towards the blade root 105 and away from the hub 108 so that the radially outer circumference of the interface 1 16 is located nearer to the blade tip than the radially inner circumference of the interface 1 16.
  • the blade/hub interface 1 16 is therefore frusto-conical when the interface is annular.
  • the frusto-conical interface is directed upwardly and outwardly and the angle a may be regarded as a "positive" angle, but in an alternative embodiment the frusto- conical interface is directed downwardly and outwardly and the angle a (which may have the same values described above) may be regarded as a "negative" angle.
  • the interface is oriented away from the blade root and towards the hub so that the radially inner circumference of the interface is located nearer to the blade tip than the radially outer circumference of the interface.
  • Such a frasto-conical blade/hub interface 1 16 provides a number of advantages.
  • the frusto- conical interface 116 permits the blade geometric taper to be initiated precisely at the free end of the blade root.
  • the root contact face is inclined or coned so that it is not perpendicular to the bolt axis or blade axis, the tendency of the blade to slide across the hub spindle contact surface is reduced.
  • such sliding forces are large due to tidal turbine blades generating large lift forces over a relatively short blade span (compared for instance to a wind turbine blade).
  • the provision of a "positive” or “negative” inclined angle for the contact surfaces of the blade root and hub results in the reaction forces from the bending moment serving to counteract the sliding force and/or the bolt preload serving to counteract the sliding force.
  • the geometric taper of the blade can be more rapid, hence reducing the drag of the blade, without excessive curvature of the laminate, which could otherwise lead to delamination of the composite material due to Brazier loads.
  • the blade is easier to laminate as the degree of double curvature in this area is reduced, i.e. the blade root can become more conical.
  • the provision of the open-ended elongated holes 124 also provides a number of technical advantages.
  • the studs can be removed from the outboard side without removing the blade, which can reduce the time taken to inspect or replace the studs.
  • the bolts can be tightened from directly outboard, allowing the open-ended elongated holes 124 to be made narrower because reduced width for torque wrench access is required.
  • the machining of the open-ended elongated holes can be done in a single cutting operation in the blade axial direction with a milling cutter. Depending on the depth of cut, the open-ended hole can be left blind so that the blade remains watertight. This can be beneficial to avoid marine fouling inside the blade. Alternatively a watertight plate can be fitted to the inside face of the hole after machining if required.
  • a bolt-style tensioner can be used instead of a stud plus nut-style tensioner as shown in Figure 4.
  • Such a bolt-style tensioner can be made more compact and removes the need for a thread on the outboard end of the stud, which determines its fatigue life. Since the only limitation on the size of the inboard end of the stud is the size of the hole in the blade through which it must pass, the thread at the inboard end can be much larger, and hence is more resistant to fatigue. Alternatively for a given size of thread, a smaller bolt can be used, allowing the elongated hole 124 to be narrower and hence the blade laminate can be made thinner and be less expensive.
  • the present invention has application in the manufacture of oscillating foil tidal turbine blades, cross-flow tidal turbine blades and axial flow tidal turbine blades, because all of these blade types have very high loading and relatively thin blade sections and their root connections can generate high shear loads.
  • the cost of maintenance and repair of submerged tidal turbines is high, for example much greater than for onshore wind turbines.
  • the preferred embodiments of the present invention provide an advantage that the constructions can eliminate the use of highly-loaded adhesive joints in an underwater environment, which enhances the reliability of the tidal turbine incorporating the tidal turbine blade.
  • the preferred embodiments of the present invention can also provide significant labour cost savings, efficiency and reliability improvements compared to other methods, particularly for an axial-flow turbine construction.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Oceanography (AREA)
  • Power Engineering (AREA)
  • Hydraulic Turbines (AREA)

Abstract

L'invention porte sur une pale de turbine (4), laquelle pale est apte à l'adaptation sur un élément de turbine (8), et laquelle pale de turbine (4) comprend une partie de montage de racine qui permet de monter une extrémité de la pale de turbine (4) sur l'élément de turbine (8) et qui est constituée par un matériau composite en résine renforcé par des fibres, la partie de montage de racine ayant une surface de montage d'extrémité pour s'accoupler avec une surface de montage complémentaire de l'élément de turbine, une pluralité de perçages allongés (22) espacés autour de la surface de montage d'extrémité de la pale et s'étendant vers l'intérieur à partir de celle-ci, et une pluralité d'ouvertures (24) dans la partie de montage de racine, chaque ouverture (24) étant située à une extrémité, éloignée vis-à-vis de la surface de montage d'extrémité, d'un perçage respectif des perçages (22), chaque ouverture (24) étant allongée dans une direction s'étendant longitudinalement le long d'un axe longitudinal du perçage allongé (22) respectif.
EP13811916.9A 2012-12-19 2013-12-18 Pale de turbine Withdrawn EP2935870A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB1222943.1A GB2509082B (en) 2012-12-19 2012-12-19 Turbine Blade
PCT/EP2013/077235 WO2014096100A1 (fr) 2012-12-19 2013-12-18 Pale de turbine

Publications (1)

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EP2935870A1 true EP2935870A1 (fr) 2015-10-28

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EP13811916.9A Withdrawn EP2935870A1 (fr) 2012-12-19 2013-12-18 Pale de turbine

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EP (1) EP2935870A1 (fr)
GB (1) GB2509082B (fr)
WO (1) WO2014096100A1 (fr)

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Publication number Priority date Publication date Assignee Title
GB2512608B (en) * 2013-04-03 2015-09-16 Aviat Entpr Ltd Rotor blade
WO2015084467A2 (fr) * 2013-09-19 2015-06-11 Obermeyer Henry K Fixation de rotor de machine hydromotrice
DK3710691T3 (da) * 2017-11-16 2022-04-11 Wobben Properties Gmbh Forbindelse af en rotorvinge med rotornavet af et vindenergianlæg
DE102018130895A1 (de) * 2018-12-04 2020-06-04 Wobben Properties Gmbh Rotor für eine Windenergieanlage und Verfahren
CN116146582B (zh) * 2023-04-17 2023-06-27 新创碳谷集团有限公司 一种分段式风电叶片螺栓连接结构及其更换方法

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Publication number Priority date Publication date Assignee Title
NL1013807C2 (nl) * 1999-12-09 2001-07-05 Aerpac Holding B V Windturbinerotor, alsmede naaf en extender daarvoor.
US20070264121A1 (en) * 2006-05-10 2007-11-15 Miller James W Torsion blade pivot windmill
GB0822681D0 (en) * 2008-12-12 2009-01-21 Aviat Entpr Ltd Rotor blades
US9995271B2 (en) * 2011-04-11 2018-06-12 Lm Wp Patent Holding A/S Wind turbine blade with tapering root bushings

Non-Patent Citations (1)

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Title
See references of WO2014096100A1 *

Also Published As

Publication number Publication date
GB201222943D0 (en) 2013-01-30
GB2509082B (en) 2015-06-17
GB2509082A (en) 2014-06-25
WO2014096100A1 (fr) 2014-06-26

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