FLUID TURBINE WITH INTEGRATED PASSIVE YAW
Example embodiments are directed to shrouded fluid turbines that include a turbine shroud and a rotor. The turbine shroud includes a an inlet, an outlet and a plurality of mixer lobes circumferentially spaced about the outlet. The rotor can be disposed within the turbine shroud and downstream of the inlet. The rotor includes a hub and at least one rotor blade engaged with the hub. The shrouded fluid turbines further include a passive yaw system for regulating a yaw of the shrouded fluid turbine. The shrouded fluid turbine defines a center of gravity and a center of pressure. The center of gravity can be offset from the center of pressure. Example embodiments are also directed to methods of yawing a shrouded fluid turbine.
1 . A shrouded fluid turbine, comprising:
a turbine shroud including an inlet, an outlet and a plurality of mixer lobes circumferentially spaced about the outlet,
a rotor disposed within the turbine shroud and downstream of the inlet, the rotor including a hub and at least one rotor blade engaged with the hub, and
a passive yaw system for regulating a yaw of the shrouded fluid turbine,
wherein the shrouded fluid turbine defines a center of gravity and a center of pressure, the center of gravity being offset from the center of pressure.
2 . The shrouded fluid turbine according to claim 1 , further comprising an ejector shroud surrounding the plurality of mixer lobes, the ejector shroud defining an ejector shroud inlet and an ejector shroud outlet.
3 . The shrouded fluid turbine according to claim 2 , wherein the plurality of mixer lobes extend downstream of the ejector shroud inlet.
4 . The shrouded fluid turbine according to claim 2 , further comprising a support structure for connecting the turbine shroud to the ejector shroud.
5 . The shrouded fluid turbine according to claim 4 , wherein the support structure provides vertical stabilization to the ejector shroud relative to the turbine shroud and provides yaw characteristics that support passive yaw of the shrouded fluid turbine.
6 . The shrouded fluid turbine according to claim 1 , wherein the turbine shroud is aerodynamically contoured.
7 . The shrouded fluid turbine according to claim 1 , further comprising a nacelle including therein electrical generation equipment.
8 . The shrouded fluid turbine according to claim 1 , further comprising a support structure rotationally engaged with the shrouded fluid turbine.
9 . The shrouded fluid turbine according to claim 1 , further comprising an active yaw system for yawing the shrouded fluid turbine into a fluid-flow direction.
10 . The shrouded fluid turbine according to claim 9 , wherein the passive yaw system is a continuous-passive yaw system and the active yaw system is at least one of a momentary-active yaw system, a controlling-active yaw system and a supporting-active yaw system.
11 . The shrouded fluid turbine according to claim 10 , wherein the passive yaw system is engaged from a cut-in fluid velocity to a cut-out fluid velocity, the controlling-active yaw system is engaged from the cut-in fluid velocity to a predetermined fluid velocity range, and a combination of the passive yaw system and the supporting-active yaw system is engaged between the predetermined fluid velocity range and the cut-out fluid velocity.
12 . The shrouded fluid turbine according to claim 11 , where the predetermined fluid velocity range is between 8 m/s and 12 m/s.
13 . The shrouded fluid turbine according to claim 9 , wherein the active yaw system further comprises brakes.
14 . The shrouded fluid turbine according to claim 13 , wherein the brakes automatically disengage during a loss of grid power to the shrouded fluid turbine.
15 . The shrouded fluid turbine according to claim 2 , wherein at least one of the turbine shroud and the ejector shroud includes faceted sides.
16 . A method of yawing a shrouded fluid turbine, comprising:
providing a shrouded fluid turbine, the shrouded fluid turbine including (i) a turbine shroud including an inlet, an outlet and a plurality of mixer lobes circumferentially spaced about the outlet, (ii) a rotor disposed within the turbine shroud and downstream of the inlet, the rotor including a hub and at least one rotor blade engaged with the hub, and (iii) a passive yaw system for regulating a yaw of the shrouded fluid turbine, wherein the shrouded fluid turbine defines a center of gravity and a center of pressure, the center of gravity being offset from the center of pressure, and
yawing the shrouded fluid turbine via the passive yaw system.
17 . The method according to claim 16 , further comprising providing an active yaw system.
18 . The method according to claim 17 , wherein the passive yaw system and the active yaw system yaw the shrouded fluid turbine into a fluid-flow direction.
19 . The method according to claim 18 , wherein the passive yaw system is a continuous-passive yaw system and the active yaw system is at least one of a momentary-active yaw system, a controlling-active yaw system and a supporting-active yaw system.
20 . The method according to claim 19 , wherein engaging the passive yaw system from a cut-in fluid velocity to a cut-out fluid velocity, engaging the controlling-active yaw system from the cut-in fluid velocity to a predetermined fluid velocity range, and engaging a combination of the passive yaw system and the supporting-active yaw system between the predetermined fluid velocity range and the cut-out fluid velocity.