Various embodiments of an airfoil and machines with airfoils are disclosed. The airfoils include a thicker leading airfoil portion and a thinner trailing airfoil portion. In one embodiment, the leading airfoil portion is formed by bending a body of the airfoil back toward itself. In another embodiment, the leading airfoil portion has a solid geometry and includes two elliptic surfaces. To prevent detachment of airflow, the leading airfoil portion includes at least two arc portions or surfaces that act to direct the airflow down to the trailing airfoil portion in a manner that stabilizes vortexes that may form in the region of changing thickness.

A ram air turbine rotor comprises at least one intra-flow path shroud structure coupled between rotor blades, along a radial position between a support disc and an outer rim. The shroud structure includes shroud sectors each coupled between a respective pair of blades. The sectors each include a first edge adjacent to leading edges of the respective pair of blades, the first edge including a first curved segment, and a second edge adjacent to trailing edges of the respective pair of blades, the second edge including a second curved segment. The curved segments are each partially defined by a respective ellipse having a semi-major axis and a semi-minor axis. The semi-major axis is a portion of a spanwise distance between the respective pair of blades. The semi-minor axis is a portion of an axial distance between the leading edge of one blade and the trailing edge of an adjacent blade.

Various embodiments of an airfoil and machines with airfoils are disclosed. The airfoils include a thicker leading airfoil portion and a thinner trailing airfoil portion. In one embodiment, the leading airfoil portion is formed by bending a body of the airfoil back toward itself. In another embodiment, the leading airfoil portion has a solid geometry and includes two elliptic surfaces. To prevent detachment of airflow, the leading airfoil portion includes at least two arc portions or surfaces that act to direct the airflow down to the trailing airfoil portion in a manner that stabilizes vortexes that may form in the region of changing thickness.

Disclosed is a wave energy power generation apparatus, comprising a plurality of wave energy collecting units. Each of the wave collecting units comprises: a potential energy collecting assembly used for collecting wave potential energy, a kinetic energy collecting assembly used for collecting wave kinetic energy and a positioning assembly used for vertically limiting and horizontally positioning buoyancy compartments. The apparatus is beneficial for improving the collection efficiency of wave energy, and simultaneously can satisfy the purposes of long-term safe and stable operation, of being adapted for scaled construction.

Disclosed is a multiple blade wind turbine (MBWT). The MBWT includes: at least one rotor comprising two closed loop tracks positioned parallel or equidistant to one another and a plurality of airfoils interspaced within the tracks. The plurality of airfoils are connected at each end to one of said tracks and are fully rotatable with respect to said closed loop tracks. A transmission is connected to one of the tracks. The track drives the transmission and an electric generator is connected to said transmission for generating electricity. The rotors are oriented vertically or horizontally with respect to a vertical support structure that is used to support the rotors. The MBWT's design allows the electric generator(s) and transmission system to be housed relatively close to ground level. This configuration reduces the mass of the central support tower and reduces the construction and ongoing maintenance costs.

A fluid connection for a hydromotive machine or fluid-control valve having a first duct and a second duct. The first duct includes a mid-portion between a first end of the first duct and a second end of the first duct that has a non-circular cross-section. A second end of the first duct is wholly within the second end of the second duct. A first end of the second duct is wholly outside of the first duct.

A hull that is part of a system for producing energy through the action of waves. The hull's shape, dimension and orientation make the system less costly and increase the energy provided by the system.

Various embodiments of an airfoil and machines with airfoils are disclosed. The airfoils include a thicker leading airfoil portion and a thinner trailing airfoil portion. In one embodiment, the leading airfoil portion is formed by bending a body of the airfoil back toward itself. In another embodiment, the leading airfoil portion has a solid geometry and includes two elliptic surfaces. To prevent detachment of airflow, the leading airfoil portion includes at least two arc portions or surfaces that act to direct the airflow down to the trailing airfoil portion in a manner that stabilizes vortexes that may form in the region of changing thickness.

A Current Energy Collection Unit (1) is provided, having a turbine (2) housed within a tubular trapezoid wall (3), forming a densely opaque circular area perpendicular to a natural direction of an upstream water volume flow line (11) capable of causing a variation in the momentum of an upstream water mass (10) absorbing energy from the upstream water mass.

The combined pump and energy recovery turbine includes at least one fluid flow pressurizing a sliding vane pump and a sliding vane energy recovery turbine that recovers energy from a second fluid flow, such as the brine discharge from an RO seawater desalination system. A cylindrical rotor has two sliding vanes in respective slots, the rotor being concentrically disposed within an oval-shaped enclosure defining two mirror image crescent-shaped chambers, each chamber having inlet and outlet passageways. The first chamber pressurizes the first fluid flow, and the second chamber functions as a second outflow-driven energy recovery turbine, thus enabling the single rotor device to operate as a pressurizing pump on the first fluid flow, and second outflow-driven energy recovery turbine recovering energy from the pressure drop in the second fluid flow.