According to some embodiments, a drum may be submerged in water and extend horizontally along a center axis between a first point on a first side of the drum and a second point on a second side of the drum opposite the first side. Three curved vanes may be attached to the drum such that the vanes, when acted upon by a water flow perpendicular to the axis, are operable to cause rotation about the axis, wherein an edge portion of each vane, located substantially opposite the drum, defines a plane substantially parallel to a plane defined by a surface of the drum located between the edge portion and the axis. An electrical generator coupled to the drum may convert rotational energy produced by the rotation about the axis into electrical energy.

Disclosed is a wind turbine blade and a method for its manufacture. A lower shell part and an upper shell part are provided, each shell part having a leading edge end and a trailing edge end. A flatback profile component and web for connecting an inner surface of the lower side shell part with an inner surface of the upper side shell part are connected. The assembly which comprises the flatback profile component and the at least one web are placed on the lower shell part and the upper shell part is mounted. The wind turbine blade comprises a flatback profile component being arranged at the trailing edge, wherein the flatback profile component is coupled by at least one distance holder with at least one web, wherein the web couples the interior surface of the upwind side shell part with the interior surface of the downwind side shell part.

Wind turbine blade having at least one longitudinal hollow element that defines an aerodynamic outer surface and an inner cavity having an inner surface. The blade also comprises at least one spar (1), disposed in the inner cavity and bonded to the inner surface by at least two bonding surfaces (13) located on bonding surfaces (2) of the spar (1). The spar (1) comprises, on at least one bonding zone (2), at least three fibre fabric layers (3) and at least one central core (4) and at least one lateral core (5) disposed between the at least three fibre fabric layers (3). This makes it possible to increase the resistance to shear stresses in the adhesive bond of the spar (1) to the inner surface of the longitudinal hollow element and decrease the required amount of adhesive.

A wind turbine assembly comprising a generally cylindrical wind turbine rotor that is supported by a rotor support and operable to rotate about a rotational axis, the rotor comprising a plurality of aerofoil blades with each aerofoil blade having a leading edge, a trailing edge, a suction surface, a pressure surface, and an aerofoil chord having a chord length between the leading edge and the trailing edge, the aerofoil blades being in a generally cylindrical arrangement around the rotational axis with the leading edges at a larger radial separation from the rotational axis than the trailing edges, and the chords being angled relative to radii through the rotational axis such that the suction surfaces and pressure surfaces respectively face generally outwardly and inwardly from and to the rotational axis, wherein the minimum separation (S) between the leading edge of a first aerofoil and the suction surface of an adjacent aerofoil is less than the chord length (L.sub.C), and wherein the location of the maximum thickness of each aerofoil blade (L.sub.Tmax) along the chord (L.sub.C)) is less than 20% of the chord length (L) from the leading edge.

Embodiments of the present invention are related to a shrouded Kaplan and shrouded propeller-type hydraulic turbine. More in particular, the embodiments relate to a blade for such shrouded turbines. An object of the embodiments of the present invention is to add a winglet on the pressure side of a blade to eliminate a large gap between the blade and the shroud, in order to improve performances, decrease marginal cavitation, and improve fish friendliness.

A rotor blade of an aerodynamic rotor of a wind turbine having a rotor axis of rotation and an outer radius, comprising a blade root for fastening to a rotor hub, a blade tip which faces away from the blade root, a blade longitudinal axis which extends from the blade root to the blade tip, a blade front edge which faces toward the front in the direction of movement of the rotor blade, a blade rear edge which faces toward the rear in the direction of movement of the rotor blade, and profile sections which change along the blade longitudinal axis, wherein each profile section has a profile chord which extends from the blade front edge to the blade rear edge, and each profile chord has an installation angle as an angle in relation to a rotor plane, wherein the installation angle from the blade root to the blade tip first decreases in a blade inner region oriented toward the blade root, increases again in a blade central region and decreases again in a blade tip region oriented toward the blade tip. A rotor of a wind turbine and to a corresponding wind turbine.

A pultruded fibrous composite strip, a spar cap made from such strips, a wind turbine rotor blade having such a spar cap and a method for making a spar cap from such strips is provided. The strip is stacked with similar strips to form the spar cap. The strip has a substantially constant cross-section defined by first and second mutually opposed and longitudinally extending sides, and by first and second longitudinal edges. The first and the second sides include first and second abutment surfaces, respectively. The first and the second abutment surfaces are non-planar. When the strip is stacked with similar strips, and subsequently integrated within shell of the wind turbine blade, the non-planar profile of the strips at least partially obviates formation of resin rich pockets at the interface of the spar cap and the shell and/or stress concentration between the edges of the spar cap and the shell.

A cross-flow fan includes a plurality of fan blades provided to be circumferentially spaced apart from each other. The fan blade has an inner edge portion arranged on the radially inner side to/from which air flows in/out, and an outer edge portion arranged on the radially outer side to/from which air flows in/out. Fan blade has a blade surface extending between the inner edge portion and the outer edge portion. The blade surface includes a pressure surface arranged on the rotation direction side of the cross-flow fan and a suction surface arranged on the back side of the pressure surface. When cut along a plane orthogonal to the rotation axis of the cross-flow fan, the fan blade has a blade cross-sectional shape in which a concave portion concave from the pressure surface is formed.

An axial ventilator has multiple fan wheel blades (2) arranged around an axis of rotation (RA) in a blade ring. At least one of the fan wheel blades (2) has an inner section (3) located on the radial inside. A blade edge section (4) directly adjoins the inner section (3) and borders a blade edge (5). The at least one fan wheel blade (2) has a local projection (6) over a radial extension of the blade edge section (4). The local projection (6) is formed as an extension of the chord length of the fan wheel blade. The projection locally enlarges the fan wheel blade (2) in the blade edge section (4). An average angle of attack (α) of the fan wheel blade (2), in relation to a plane of rotation (RE), of the fan wheel (1), is larger than an average angle of attack (β) of the projection (6), in relation to the plane of rotation (RE).

A wind turbine blade is described having a de-icing system which is arranged to heat at least a portion of the leading edge of the wind turbine blade, to prevent the formation of ice on the blade, or to remove any existing surface ice. The de-icing system comprises insulated flow channels which are arranged to circulate a heated fluid from a heating element to the tip end of the blade, and to de-ice the blade leading edge starting from the tip end towards the root end of the blade. The de-icing system is arranged to operate in the outboard portion of the blade, where the de-icing effect provides the most benefits to turbine operation. Further features of the de-icing system include an improved mounting arrangement of the de-icing system, an improved tip end configuration of the de-icing system, and providing portions of the de-icing system as double-walled inflatable insulating tubes.