초록 ▼

A tiered structural assembly for wind turbine blades that reduces stress on the airfoil profile is shown. The wind turbine blades and rotor assemblies for capturing the wind resources show significant improvements in both cost of manufacture and site assembly compared to three-bladed horizontal axis

A tiered structural assembly for wind turbine blades that reduces stress on the airfoil profile is shown. The wind turbine blades and rotor assemblies for capturing the wind resources show significant improvements in both cost of manufacture and site assembly compared to three-bladed horizontal axis turbines. A simple, easily manufactured blade pivoting mechanism is shown to improve the performance of vertical axis turbines. A related improvement for varying blade pitch along the axis of horizontal axis turbine blades allows for production using continuous mass-production methods rather than the labor and cost intensive current practice of molding the blades. The blade assemblies are scalable and suited to areas with moderate wind resources.

대표청구항 ▼

1. A blade construction for a wind turbine comprising an assembly of an airfoil profile and an unsymmetrical I beam, said airfoil profile elongated in a first direction and having;a single interior surface having features congruent to said unsymmetrical I beam in at least three locations of contact

1. A blade construction for a wind turbine comprising an assembly of an airfoil profile and an unsymmetrical I beam, said airfoil profile elongated in a first direction and having;a single interior surface having features congruent to said unsymmetrical I beam in at least three locations of contact for receiving and aligning said unsymmetrical I beam along the length of said airfoil profile, andan exterior surface corresponding to a uniform aerodynamic shape along the length of said airfoil profile with a leading edge and a trailing edge, said leading edge and said trailing edge connected by a chord line, with said airfoil profile divided by said chord line into a convex upper side and an opposing lower side,said interior surface being roughly congruent to said exterior surface except at said at least three locations of contact,said unsymmetrical I beam elongated in said first direction and having perpendicular to said first direction; a web section of constant width and thickness with a roughly flat medial plane and a longitudinal central axis,said web section integral with two flanges; a first flange near said leading edge and a second flange near said trailing edge, with both said flanges aligned roughly perpendicular to said medial plane and each having flange tips,said flange tips positioned asymmetrically about said central axis, said first flange and said second flange having constant widths along said first direction and having variable widths, relative to one another, withboth said flanges directly bonded to said single interior surface at said flange tips along roughly parallel lines extending from said at least three locations of contact in said completed blade construction along the length of said airfoil profile,said medial plane forming a designed angle with said chord line perpendicular to said first direction and said blade construction defining a surface of rotation during operation of said wind turbine, withsaid web section, said lower side between said two flanges and said two flanges comprising a roughly triangular structural member running the length of said blade construction, andsaid web section, said upper side between said two flanges and said two flanges comprising a shallow box beam structural member running the length of said blade constructionsaid web section comprising a principal attachment surface to said wind turbine near at least one end of said blade construction with said wind turbine additionally including; at least one mating hub that overlaps said attachment surface and conventional fasteners that secure said attachment surface to said at least one mating hub,whereby: said triangular structural member and said box beam structural member form a tiered structural assembly running along the length of said blade construction and said tiered assembly resists deformation by aerodynamic and rotational forces incurred during operation of said wind turbine. 2. The blade construction of claim 1, wherein said first flange forms a shallow draft angle with said second flange when viewed from the perspective of said trailing edge, said flange tips of said at least one flange directly connected to said congruent features of said single interior surface withsaid attachment surface located at one end of said blade construction and with said wind turbine including one mating hub that overlaps said attachment surface and conventional fasteners that secure said attachment surface to said mating hub, with said surface of rotation lying roughly perpendicular to a rotational axis of said wind turbine. 3. The blade construction of claim 1, wherein said attachment surface is located near both ends of said airfoil profile, and with said wind turbine having two mating hubs that overlap said attachment surface near both ends of said blade construction and conventional fasteners that secure said attachment surface to said two mating hubs, said surface of rotation being co-axial to a rotational axis of said wind turbinewhereby: said two mating hubs, said designed angle and said variable widths of said two flanges can define an initial angle of attack of said blade construction measured between said chord line and said surface of rotation. 4. The blade construction of claim 3, wherein at least parts of said two flanges and said airfoil profile have been removed in selected areas near both ends of said blade construction, andsaid attachment surface is retained near both ends of said blade construction, with said wind turbine still including; said two mating hubs that overlap said attachment surface at both ends of said blade construction and said conventional fasteners that secure said attachment surface to said mating hubs, whereina limited amount of torsional displacement of said blade construction about said centerline of said web section relative to said initial angle of attack can occur within said selected areas where said two mating hubs do not overlap said attachment surface in response to said aerodynamic and rotational forces, whereby: said limited amount of torsional displacement can allow a limited change to said initial angle of attack of said blade construction during a circuit of rotation around said surface of rotation where said limited change can improve the performance of said wind turbine. 5. The blade construction of claim 1, wherein at least three locations of contact comprise three step transitions between thickened areas of said airfoil profile and relatively thinner areas of said airfoil profile at said interior surface, each of said thickened areas having a linear extent of slightly less than the width of said web section when projected onto said medial plane,whereby: said airfoil profile can be precisely aligned and directly bonded to said unsymmetrical I beam. 6. The blade construction of claim 1, wherein said flange tips are directly bonded to said airfoil portion using an adhesive. 7. The blade construction of claim 1, wherein said unsymmetrical I beam is composed of a fibrous reinforcement within a matrix of resin material, with said fibrous reinforcement selected from the group consisting of;fiberglass unidirectional rovings and stitched triaxial fiberglass fabric and non-woven glass fabric and 0/90 glass fabrics,and said resin material is selected from the group consisting of; epoxy polymers and urethane polymers and phenolic polymers and polyester polymers and vinyl based polymers. 8. The blade construction of claim 1, wherein said overlap between said principal attachment surface and said at least one mating hub occurs within said shallow box beam structural member. 9. The blade construction of claim 1, wherein said overlap between said principal attachment surface and said at least one mating hub occurs within said roughly triangular structural member. 10. A strut for a wind turbine comprising a tubular profile and an I beam, said tubular profile elongated in a first direction and having;a single interior surface having features congruent to said I beam in four locations of contact for receiving and aligning said I beam along the length of said tubular profile,said I beam elongated in a first direction and having perpendicular to said first direction;a web portion integral with two flanges, each having two flange tips said web portion having a medial plane perpendicular to each of said two flanges and a longitudinal central axis parallel to each of said two flanges, withsaid two flanges directly bonded to said interior surface at said flange tips along roughly parallel lines extending from said four locations of contact, along the length of said I beam,said tubular profile having a roughly cylindrical exterior surface, with said interior surface being roughly congruent to said exterior surface except at said four locations of contact, said web portion comprising a principal attachment surface to said wind turbine near both ends of said strut with said wind turbine additionally including two mating hubs that overlap said attachment surface and conventional fasteners that secure said attachment surface to said two hubs,whereby: said tubular profile can be strengthened at mid-span and said two hubs can be additionally utilized with other wind turbine components.