A fluid power generator can enhance power generation efficiency by efficiently using the drag force of wind without increasing the size of blades, and includes: an ascending air current-forming body provided at a rotary shaft; a plurality of spiral blades which are spirally formed along the outer circumferential surface of the ascending air current-forming body; and a generator which generates electricity by rotation of the ascending air current-forming body.

A centrifugal compressor impeller includes a plurality of blades on a front side that extend from a first axial side to an outer radial end of the impeller. The centrifugal impeller includes a back side having a nonlinear backwall. The backwall can include a flat area hear a bore of impeller, a flat area near a tip of the impeller, and a convex surface between the flat areas of the bore and the tip. In some forms the impeller further includes a concave surface between the convex surface and the tip to form an s-shape. A transition or inflection point can denote the change from convex to concave. The convex and/or concave surfaces can take any variety of forms such as constant radius sections and/or compound curves.

Wind turbine blade having a length L, an airfoil with a chord C, and a first Gurney flap attached to the pressure or the suction surface of the airfoil near the trailing edge of the wind turbine blade. The first Gurney flap extends along at least 50% of the length of the outer ⅓rd of the wind turbine blade. By mounting the Gurney flap to the outer portion of the blade, the lift of the outer portion of the blade can be increased or decreased depending on the conditions in which the wind turbine is operating.

A rotor blade of a wind turbine, to an associated wind turbine and to an associated method. A rotor blade for a wind turbine, which extends in the longitudinal direction with a profile course from a blade connector to a blade tip, wherein the profile course comprises a course of a lift coefficient, comprising a hub portion adjacent to the blade connector and a tip portion adjacent to the blade tip, a middle portion adjacent to the hub portion and to the tip portion, wherein the middle portion substantially comprises those profile sections which have a relative profile thickness, which is defined as the ratio of maximum profile thickness to profile depth, of between 20% and 30%, and wherein the middle portion comprises a local minimum of the course of the lift coefficient.

A reinforcing structure for a wind turbine blade is in the form of an elongate stack of layers of pultruded fibrous composite strips supported within a U-shaped channel. The length of each layer is slightly different to create a taper at the ends of the stack; the centre of the stack has five layers, and each end has a single layer. The ends of each layer are chamfered, and the stack is coated with a thin flexible pultruded fibrous composite strip extending the full length of the stack. The reinforcing structure extends along a curved path within the outer shell of the blade. The regions of the outer shell of the blade on either side of the reinforcing structure are filled with structural foam, and the reinforcing structure and the foam are both sandwiched between an inner skin and an outer skin.

An impeller for wind power generation includes: a plurality of blades; and a hub which is provided with a rotating shaft at a center and around which the plurality of blades are arranged at substantially equal intervals in a circumferential direction. The blade is formed to extend while widening a width toward an outer periphery of the impeller, a line segment connecting a leading edge and a trailing edge of the blade is inclined at an angle of approximately 10 degrees or more and approximately 20 degrees or less with respect to a plane perpendicular to a rotating shaft of the impeller, and in the plurality of blades, a trailing edge of a blade on a front side in a rotation direction of the impeller and a leading edge of a blade on a rear side in the rotation direction partially overlap each other in a front view of the impeller.

A rotor blade of a wind turbine, to an associated wind turbine and to an associated method. A rotor blade for a wind turbine which extends in the longitudinal direction with a profile course from a blade connector to a blade tip, wherein the profile course comprises a course of a lift coefficient, comprising a hub portion adjacent to the blade connector and a tip portion adjacent to the blade tip, a middle portion adjacent to the hub portion and to the tip portion, wherein the middle portion substantially comprises those profile sections which have a relative profile thickness, which is defined as the ratio of maximum profile thickness to profile depth, of between 20% and 30%, and wherein the middle portion comprises a local minimum of the course of the lift coefficient.

A rotor blade for a wind energy installation includes a blade root, a blade tip, and at least one rotor blade shell extending in a longitudinal direction from the blade root to the blade tip, and having an inner shell region and an outer shell region. The inner shell region includes a first fiber composite with at least two first fiber layers, and the outer shell region includes a second fiber composite with at least two second fiber layers. The first and second fiber layers extend substantially in the longitudinal direction. At least a first fiber layer of the first fiber composite terminates in the region of at least one end position in the longitudinal direction, whereas the remaining first fiber layers extend beyond the end position. At least a second fiber layer of the second fiber composite terminates in the region of the end position in the longitudinal direction, whereas the remaining second fiber layers extend beyond the end position.

A centrifugal compressor impeller includes a plurality of blades on a front side that extend from a first axial side to an outer radial end of the impeller. The centrifugal impeller includes a back side having a nonlinear backwall. The backwall can include a flat area hear a bore of impeller, a flat area near a tip of the impeller, and a convex surface between the flat areas of the bore and the tip. In some forms the impeller further includes a concave surface between the convex surface and the tip to form an s-shape. A transition or inflection point can denote the change from convex to concave. The convex and/or concave surfaces can take any variety of forms such as constant radius sections and/or compound curves.

A propeller fan includes a rotary shaft portion that rotates around an axial center and a plurality of blades disposed around an outer circumferential portion of the rotary shaft portion. Each of the plurality of blades has at least one recessed portion that opens at a trailing edge of the blade. The at least one recessed portion has a first side that is close to an inner circumference of the blade. The first side stretches from the trailing edge toward a leading edge of the blade, and is bent toward an outer circumference of the blade.