Segmented wind turbine
Disclosed are wind turbines comprising a turbine shroud and optionally an ejector shroud. The shrouds are segmented, or in other words have longitudinal spaces between segments. Such wind turbines have reduced drag load, particularly those loads due to off-axis wind forces.
1. A wind turbine comprising a turbine shroud, the turbine shroud being formed from:
a plurality of turbine shroud segments, each turbine shroud segment having a cambered cross-section and having a first mixing lobe formed on a trailing edge;
wherein the turbine shroud segments are spaced circumferentially apart to form a discontinuous airfoil, second mixing lobes being defined by the spaces between the turbine shroud segments, the turbine shroud segments being oriented to produce low pressure on an interior side of the turbine shroud.
2. The wind turbine of claim 1 , wherein the turbine shroud further comprises a continuous leading edge ring member.
3. The wind turbine of claim 1 , wherein the turbine shroud segments form a discontinuous leading edge of the turbine shroud.
4. The wind turbine of claim 1 , further comprising a center body, the turbine shroud segments being attached to the center body.
5. The wind turbine of claim 1 , wherein the mixing lobe has a circumferential surface and two side surfaces.
6. The wind turbine of claim 1 , further comprising an ejector shroud located concentrically about and overlapping an outlet end of the turbine shroud, the ejector shroud having an airfoil shape that produces low pressure on an interior side of the ejector shroud.
7. The wind turbine of claim 6 , wherein the ejector shroud is formed from a plurality of ejector shroud segments.
8. The wind turbine of claim 7 , wherein the ejector shroud segments are spaced circumferentially apart to form a discontinuous airfoil.
9. The wind turbine of claim 8 , wherein spaces between the ejector shroud segments are covered with a thin film material to form a continuous surface.
10. The wind turbine of claim 7 , wherein at least one ejector shroud segment is attached to each turbine shroud segment by at least one support member.
11. The wind turbine of claim 10 , wherein two ejector shroud segments are attached to each turbine shroud segment.
12. The wind turbine of claim 7 , wherein the turbine shroud further comprises a continuous leading edge ring member, and each ejector shroud segment is attached to the leading edge ring member by at least one support member.
13. The wind turbine of claim 7 , wherein each ejector shroud segment is located over a first mixing lobe.
14. The wind turbine of claim 7 , wherein each ejector shroud segment is located over a second mixing lobe.
15. The wind turbine of claim 1 , wherein each turbine shroud segment comprises an inflatable member.
16. The wind turbine of claim 1 , wherein each turbine shroud segment comprises a skeleton and a skin covering the skeleton, the skin being formed from a fabric or a polymer.
17. The wind turbine of claim 16 , wherein the fabric is a fiberglass, polyester, or polyamide.
18. The wind turbine of claim 16 , wherein the polymer is a fluoropolymer, a polyolefin, a polyethylene terephthalate, a polyester, an ethylene vinyl acetate, a polyurethane, polybutylene terephthatlate, or polytrimethylene terephthalate.
19. A wind turbine comprising:
a continuous turbine shroud and an ejector shroud located concentrically about an outlet end of the turbine shroud;
wherein the turbine shroud comprises a leading edge ring member and a plurality of mixing lobes along a trailing edge, the leading edge ring member having an airfoil shape that produces low pressure on an inside of the turbine shroud;
wherein the ejector shroud is formed from a plurality of ejector shroud segments attached to the turbine shroud; and
wherein the ejector shroud segments are spaced circumferentially apart to form a discontinuous airfoil shape and oriented to produce low pressure on an inside of the ejector shroud.
20. The wind turbine of claim 19 , wherein each ejector shroud segment is attached to the leading edge ring member by at least one support member.
21. The wind turbine of claim 19 , wherein each ejector shroud segment is attached to a turbine shroud mixing lobe by at least one support member.
22. A method of making a wind turbine comprising:
(a) providing a wind driven turbine;
(b) forming a plurality of turbine shroud segments having an airfoil cross-section with a first mixing lobe on a trailing edge; and
(c) disposing the turbine shroud segments about the turbine in circumferentially spaced arrangement to form a segmented turbine shroud, the spaces between the segments defining second mixing lobes, the turbine shroud segments being oriented to produce low pressure on an interior side of the turbine shroud.
23. The method defined in claim 22 , further comprising disposing an ejector shroud at the trailing edge of the turbine shroud to partially enclose the first and second mixing lobes of the turbine shroud, the ejector shroud including a ring airfoil that produces low pressure on an interior side of the ejector shroud.
24. The method defined in claim 23 , wherein the step of disposing an ejector shroud includes forming a plurality of spaced ejector shroud segments about the trailing edge of the turbine shroud.