Patent Application
20120134829
According to a first aspect, the present disclosure relates to a fluid turbine comprising a rotor and a phase-adjustable mechanism. The rotor has an axis of rotation, and comprises at least two rotor blades disposed at a radius from the axis of rotation, each rotor blade having a pitch axis and a variable pitch angle. The phase-adjustable mechanism is operable to control the pitch angle of at least one rotor blade about its pitch axis and to vary the pitch angle of the rotor blade from a first pitch angle at a first circumferential location about the axis of rotation to a second pitch angle at a second circumferential location about the axis of rotation.
According to a second aspect, the present disclosure relates to a fluid turbine comprising a rotor and a pitch angle control mechanism. The rotor has an axis of rotation, and comprises at least two rotor blades disposed at a radius from the axis of rotation, each rotor blade having a first end, a second end, a first mounting point, a second mounting point, a pitch axis and a variable pitch angle, each of the first and second mounting points being disposed inboard of the first and second ends. The pitch angle control mechanism is operable to control the pitch angle of at least one rotor blade about its pitch axis and to vary the pitch angle of the rotor blade from a first pitch angle at a first circumferential location about the axis of rotation to a second pitch angle at a second circumferential location about the axis of rotation.
According to a third aspect, the present disclosure relates to a fluid turbine comprising a rotor and a pitch angle control mechanism. The rotor has an axis of rotation and comprises a first hub, a second hub, an array of at least two struts, having strut covers disposed thereabout, extending from each of the first and second hubs, and at least two rotor blades, each secured to the distal end of a strut and having a pitch axis and a variable pitch angle. The mechanism is operable to control the pitch angle of at least one rotor blade about its pitch axis and to vary the pitch angle of the rotor blade from a first pitch angle at a first circumferential location about the axis of rotation to a second pitch angle at a second circumferential location about the axis of rotation.
A system and method of the present patent application will now be described with reference to various examples of how the embodiments can best be made and used. Like reference numerals are used throughout the description and several views of the drawings to indicate like or corresponding parts, wherein the various elements are not necessarily drawn to scale.
Structurally, turbine 100 consists of a rotor assembly comprising a torque tube 102. Torque tube 102 is designed to prevent rotor hubs 108 from rotating independently of one another. Torque tube 102 is oriented along a central axis which is intended to be disposed generally perpendicular to the direction of fluid flow. The turbine 100 comprises arrays of radially-disposed struts 104, each mounted to one of rotor hubs 108 at its proximal end and a rotor blade 106 at its distal end. Braces 110 between the struts provide additional structural integrity. The rotor blades 106 shown in
The rotor blades 106 are pivotably attached to the struts 104 in such a manner as to allow the rotor blades 106 to be individually pivoted with respect to the axis of rotation of turbine 100, thus altering the pitch angle of each rotor blade 106 with respect to the direction of fluid flow through turbine 100. The angle of the rotor blades may be controlled via mechanical linkages, hydraulics, pneumatics, linear or rotary electromechanical actuators, or any combination thereof. In certain embodiments, the rotor pitch angle profile may be controlled by a cam-and-follower mechanism operating in concert with one or more of the above systems of actuation, as set forth in further detail below.
Each actuation rod 208 is secured to a rocker assembly 206 at its proximal end and to a rotor blade at its distal end. Each actuation rod 208 controls the pitch of a particular rotor blade according to the position of a particular rocker assembly 206, which is, in turn, controlled by the profile of the outer surface of the cam 204 at the point of contact between the cam 204 and the cam follower of the rocker assembly 206. Thus, a rotor blade at a given radial location will be articulated to a given blade pitch. As a rotor blade moves about the axis of rotation of the rotor, it will be articulated according to the pattern of the cam.
A clocking motor 222 actuates a clocking mechanism 220 secured to the cam 204. The clocking mechanism is operable to vary the phase relationship between the cam 204 and the rotor blades 106 by advancing or retarding the angular position of the cam 204 with respect to the angular position of the rotor blades 106. The structure of the clocking mechanism is set forth in further detail below.
Within worm gear assembly 230, the helical worm teeth 234 of worm gear 232 mesh with the helical gear teeth 236 of gear 238. As the worm gear 232 rotates, the helical worm teeth 234 exert pressure on the helical gear teeth 236, thus imparting a torque on gear 238, which is secured to cam 204. Through the use of clocking mechanism 220, the clocking motor 222 is able to vary the angle of cam 204, and thereby vary the phase of the cam profile with respect to the rotor blades in order to optimize the blade pitch profile to match the prevailing conditions, which may include fluid velocity, fluid flow direction, fluid turbulence and fluid density, as examples.
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It is believed that the operation and construction of the embodiments of the present patent application will be apparent from the detailed description set forth above. While the exemplary embodiments shown and described may have been characterized as preferred, it should be readily understood that various changes and modifications could be made therein without departing from the scope of the present invention as set forth herein.
