Hydroelectric/hydrokinetic turbine and methods for making and using same

A unidirectional hydrokinetic turbine, having a water entrance end and a water exit end defining a direction of water flow through the turbine, comprising:

• a generally cylindrical accelerator shroud that comprises a radially inner wall and a radially outer wall spaced apart from the radially inner wall, to form a radial wall cross-section that defines within its cylindrical cross-section a water flow area that contains therein structure that consists essentially of an integral hydrokinetic force-generating member that rotates during force generation within the accelerator shroud, the integral force generating member comprising:
• a center hub member having an open center surrounded by an inner wall and having a hydrofoil profile;
• and
• a plurality of rotor blades, each rotor blade having two edges and extending radially outwardly from a radially inner base end thereof, at which base end each rotor blade is mounted on said center hub member for rotation therewith, said rotor blades terminating at radially outer blade tips, wherein said force-generating member is mounted at said outer blade tips for its support and for rotation, within the wall cross-section of said accelerator shroud;
• wherein the accelerator shroud has a forward portion upstream of the rotor blades and a rearward portion downstream of the rotor blades, comprising a hydrofoil shape with a generally S-shaped profile in which a radially outer surface comprises a forward convex portion and a rearward concave portion, and the radially inner surface comprises a rearward convex portion and a forward portion, measured from the rotor blades to the water entrance end that has a shape that is either straight or concave;
• and
• wherein the radially inner surface of the forward portion of the generally S-shaped profile is concave.

A unidirectional hydrokinetic turbine having a water entrance end and a water exit end defining a direction of water flow through the turbine, comprising:

• a generally cylindrical accelerator shroud that has a wall cross-section that comprises an asymmetrical hydrofoil shape and defines within its cylindrical cross-section a flow area, said hydrofoil shape serving to accelerate the flow of water through the accelerator shroud and to create a negative pressure field behind the accelerator shroud, in the direction of water flow;
• a rotor assembly that is mounted for rotation within the accelerator shroud around an axis that is generally parallel to the direction of water flow through the turbine, the rotor assembly comprising:
• a plurality of rotor blades extending radially outwardly from an open center of the turbine and terminating at rotor blade tips, which blades have an asymmetrical hydrofoil-shaped cross-sectional configuration, wherein said blades have a profile thickness at their radially outer ends that is greater than the profile thickness at their radially inner ends;
• and
• a rotor outer ring to which the blade tips are directly attached, and the outer ring being configured to support the rotor assembly within the accelerator shroud and having a radially outer circumference which is configured for rotation within said accelerator shroud wall cross-section;
• and
• a first annular diffuser comprising, a generally cylindrical ring member that has a wall cross-section comprising an asymmetrical hydrofoil shape, said annular diffuser having a diameter greater than the diameter of said accelerator shroud, being radially spaced from said accelerator shroud, and being positioned behind the accelerator shroud, in the direction of water flow through the turbine, whereby the hydrofoil shape of the annular diffuser serves to accelerate the flow of water through the annular diffuser and to create a negative pressure field behind the annular diffuser, and in cooperation with the hydrofoil of said accelerator shroud and said blades to augment acceleration of water flow through the accelerator shroud at the rotor assembly.