There is provided a turbine with a turbine body, a support frame, and a generator. The turbine body has a plurality of turbine blades, a shaft defining a rotational axis, and a bottom apex. Each of the turbine blades has a lower edge, and the lower edges taper upward relative to the bottom apex such that the lower edges trace a convex surface as the turbine body rotates about the rotational axis. The support frame is connected to the shaft by an angularly adjustable connection that adjusts the angle of the shaft relative to the support frame. The angularly adjustable connection permits rotation of the shaft about the rotational axis, and the generator is powered by the rotation of the shaft.

An impeller includes: a disc having a disc shape; a plurality of blades formed on a surface facing a first side in an axial direction of the disc; and a cover surrounding the plurality of blades. The cover includes: an inner circumferential surface connected to the blades with a diameter decreasing from the second side toward a first side in the axial direction; and a distal end surface extending from an end portion of the inner circumferential surface on the first side in the axial direction toward the outside in a radial direction and facing the first side in the axial direction. A front edge portion extends from a boundary between the inner circumferential surface and the distal end surface toward the inside in the radial direction.

Fan for ovens for cooking foods, which comprises: a support plate arranged substantially orthogonal to the rotation axis of the fan; and multiple blades projectingly fixed on the support plate and radially arranged around the rotation axis. Each blade of the fan is provided with an internal edge, which is shaped with a convex portion that is projectingly extended between a first and a second concavity of the internal edge itself.

A heat dissipation fan including a hub and a plurality of heat dissipation blades is provided. The heat dissipation blades are arranged around the periphery of the hub. Each of the heat dissipation blades includes a curved surface body and a flow guiding portion. The curved surface body has a pressure bearing surface and a negative pressing surface opposite to the pressure bearing surface. The flow guiding portion is connected to the curved surface body. The flow guiding portion has a concave surface and a convex surface opposite to the concave surface, wherein the concave surface is recessed in the pressure bearing surface and the convex surface protrudes outward from the negative pressing surface.

A drag-based wind turbine device is disclosed. The device is an improved wind turbine comprised of two sets of stacked and coupled, drag-based vertical axis wind turbines, wherein drag from the first turbine helps propel the second turbine. Additionally, the surface of the first turbine is convex to ensure wind is always deflected toward the second turbine, wherein the wind is then received by the concave side of the second turbine. Further, the blades are arranged in a horizontal and sloping manner. In the convex position, each slope blade deflects incoming wind to the other set of turbines in a concave direction. Additionally, the gap between two turbines can be adjusted for different wind/current speeds, viscosities, compressibility, and densities for the best efficiency.

A blade for a wind turbine defines an airfoil with a leading edge section and a trailing edge section, notably a flat-back trailing edge. A rounded connecting section interconnects a pressure side section of the airfoil and the trailing edge section. The rounded connecting section attaches to the pressure side section at a transition point, in which the pressure side section's tangent does not coincide with the rounded connecting section's tangent, so that the outer surface of the airfoil has a sharp corner at said transition point. The truncated radius, i.e. geometrical discontinuity, thus formed at the transition between the pressure side section and the trailing edge section increases the aerodynamically effective surface of the pressure side and enables forced and hence controlled flow separation without compromising ease of manufacture and structural stability of a fiber-reinforced structure making up a shell of the blade.

Provided is a blade capable of efficiently utilizing low-velocity fluid. The blade includes a main wing component, the main wing component has a streamlined cross section, an outer profile of which forms a first airfoil, the blade further includes a head wing piece in form of a sheet, the head wing piece has an arc-shaped cross section with a convex surface at one side and a concave surface at the other side, the head wing piece is arranged obliquely above a leading-edge point of the main wing component with the concave surface of the head wing piece facing the main wing component and a first ventilation space is formed between the head wing piece and the main wing component. By improving the configuration of the wing pieces of the blade, Cp of the blade is improved, and the manufacture cost of the blade can be significantly reduced.

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.

An exhaust diffuser for a gas turbine includes an annular duct. A row of struts is arranged in the duct. In a region downstream of the trailing edges of the struts, the cross-sectional area of the duct decreases to a local minimum and then increases again towards the outlet end of the duct. Thereby the gas flow is locally accelerated downstream of the struts. This stabilizes the boundary layer of the flow in this region and leads to a marked increase in pressure recovery for a wide range of operating conditions.

A radial compressor has at least one compressor stage. The compressor stage includes: an impeller having moving blades on a rotor side arranged in a flow channel of the compressor stage. The flow channel is bounded by a hub contour and a housing contour or cover disc contour. Each moving blade has a flow inlet edge and a flow outlet edge. In the region of the compressor stage on the hub contour of the flow channel, initially a curvature change from a first concave curvature into a convex curvature and following this a curvature change from the convex curvature into a second concave curvature is formed; and/or on the housing contour or cover disc contour of the flow channel, initially a curvature change from a first convex curvature into a concave curvature and following this a curvature change from the concave curvature into a second convex curvature is formed.