CROSS-REFERENCE TO RELATED APPLICATIONS
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U.S. Utility patent application Ser. No. 12/803,079 Filed Jun. 18, 2010, Applicant: Keith Michael Werle, Atlanta, Ga., U.S. Provisional Patent Application No. 61/269,606 Filed Jun. 26, 2009, “Method and Apparatus to Improve Wake Flow and Power Production of Wind and Water Turbines”.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
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Not Applicable
REFERENCE TO SEQUENCE LUSTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX
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Not Applicable
BACKGROUND OF THE INVENTION
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The present invention is in the general field of turbines. More particularly, the present invention is in the technical field of wind turbines and water turbines.
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One of the fundamental principals governing all wind turbines, open-flow hydro (water) turbines and ocean tidal or current turbines is that the total power that can be harvested from a given flow of air or fluid is constrained by, among other things, the velocity and pressure of the fluid or air in the wake of the rotor. In layman's terms, as the water or air passes through a turbine, the turbine harvests energy from the flow across the turbine blades. After passing through the turbine, the air or water has less energy than it did before passing through the turbine. Since the volume of the flow is unchanged by the turbine, the lower energy flow behind the turbine has a reduced average pressure. As this low energy/low pressure flow moves downstream, it's pressure must rise back to the overall ambient level, which causes the flow velocity to decrease as it proceeds aft of the turbine. This slower moving air or fluid in the wake behind the turbine impacts the upstream flow by “damning up” the flow—thus limiting the flow speed and the volume at the turbine rotor.
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This principal is at the heart of what is known as the “Betz” limit. First documented by A. Betz in 1926, the calculated theoretical limit of an “open flow” rotor to convert fluid (or wind) power to rotating power is 59.3% of the total energy or power of the ambient, or unobstructed flow contained within the swept area of the turbine rotor. This theoretical limit, or maximum efficiency is derived from the ratio of the ambient up-stream velocity (V1) and the terminal, or wake velocity of the fluid or air right after it passes through the turbine rotor (V2).
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Ducted or shrouded turbines are not subject to the “Betz” limit and often achieve efficiencies well above the 59.3% maximum for open-flow turbines. A recent theoretical breakthrough for calculating the maximum efficiency for ducted or shrouded turbines (with and without injection of bypass fluid), like their open-flow counterparts, shows that they are still subject to the same impacts from their wake-flow velocities.
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However, the duct or shroud around a turbine offers designers opportunities to employ a number of aerodynamic effects to improve the wake flow. These effects can be in the form of vanes or crenulated edges designed to induce down-stream axial vortices in the wake flow. These entrained vortices can rapidly mix higher energy bypass flow from outside the shroud with lower energy, slower moving flow in the wake. The impact of this is to more rapidly “mix-out” the wake, and increase the efficiency of the turbine. This is also referred to as energizing, or re-energizing the wake-flow.
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The impact of this is to increase the velocities of the flow in the wake area and more rapidly clear the low-energy, slower moving flows from the back of the turbine. This allows more air or fluid to pass through the turbine, at higher velocity, and thus more energy can be captured.
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However, these methods, which represent the prior art in the field, are limited by the flow area at the circumference, or outer diameter of the shroud. Prior art is not only limited by the total area at the boundary, but it is also limited by a number of other constraints—including the ability to capture energy from a particular target area in or around the primary or bypass flow and re-direct that energy to specific area within the wake-flow.
BRIEF SUMMARY OF THE INVENTION
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The present invention is method and apparatus to directly inject high-energy fluid or air directly into the wake flow region of a wind or water turbine, thereby re-energizing the wake flow and more rapidly “mixing out” the slower moving air or fluid behind a turbine rotor.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
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FIG. 1. is a side view of the present invention deployed on a ducted open flow hydro-turbine.
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FIG. 2. is a frontal view of the embodiment of present invention shown in FIG. 1.
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FIG. 3. is a side view of the present invention with two wake flow injectors installed on a ducted open flow hydro-turbine of similar embodiment to FIG. 1.
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FIG. 4. is a frontal view of the present invention with two wake flow injectors installed on a ducted open flow hydro-turbine of similar embodiment to FIG. 1.
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FIG. 4A. is a frontal view of the present invention with four wake flow injectors installed on a ducted open flow hydro-turbine of similar embodiment to FIG. 1.
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FIG. 5. is a top view of an alternate embodiment of the present invention. In this embodiment, there are four wake flow injectors deployed on an open flow tidal turbine designed to extract energy from the flow of water into and out of an ocean tidal area. During alternating incoming and outgoing tidal flows, the flow of water is from right to left or left to right on the figure presented. There are two wake flow injectors deployed in each of the relevant flow directions. A simple flap or closing mechanism 90 is added to the outlet of wake flow injector to prevent the reversing flow into the outlets of each wake flow injector during reverse flow periods.
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FIG. 6. is a side view of the embodiment of the present invention shown in FIG. 5.
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FIG. 7. is a frontal view of the embodiment of the present invention shown in FIG. 5.
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FIG. 8. is a top view of an alternate embodiment of the present invention. In this embodiment, two wake flow injectors 10 have separate inlets 20 but share a single outlet 30A within the wake flow region.
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FIG. 8A. is a frontal view of the embodiment of the present invention shown in FIG. 8.
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FIG. 9. is a top view of an alternate embodiment of the present invention. In this embodiment, there are three wake flow injectors. Two wake flow injectors outside the upstream diameter of the shroud or duct intake as shown above, as well as a third wake flow injector in the center of the shroud or duct. This center wake flow injector has an inlet 20, a pipe or tube 10 passing through the center axel area, and an outlet 30 behind the rotor or turbine blades.
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FIG. 10. is a top view of an alternate embodiment of the present invention similar to that shown in FIG. 9. In this embodiment, the center wake flow injector has a different diameter and length than the two radial, or perimeter wake flow injectors.
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FIG. 11. is a top view of an alternate embodiment of the present invention similar to that shown in FIG. 9. In this embodiment, the center wake flow injector has a larger diameter and shorter length than the two radial, or perimeter wake flow injectors. In this embodiment, the turbine rotor or blades are centered around either a large diameter axel or is of a “centerless” or hubless” design configuration. The intake 20 of the central wake flow injector is just in front of the turbine rotors and the outlet 30 is just behind the turbine rotor and just inside the wake flow area.
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FIG. 12. is a top view of an alternate embodiment of the present invention similar to that shown in FIG. 11. In this embodiment, the three wake flow injectors are deployed on a turbine with a straight duct or shroud.
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FIG. 12A. is a frontal view of the alternate embodiment presented in FIG. 12.
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FIG. 13. is a top view of an alternate embodiment of the present invention. In this embodiment, only a single centered wake flow injector is deployed on a turbine with a short, asymmetric shroud or duct.
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FIG. 14. is a top view of an alternate embodiment of the present invention. In this embodiment, only a single centered wake flow injector is deployed on a turbine with a short, symmetric shroud or duct.
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FIG. 14A. is a frontal view of an alternate embodiment of the present invention shown in FIG. 14.
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FIG. 15. is a top view of an alternate embodiment of the present invention. In this embodiment, only a single centered wake flow injector is deployed on a turbine with a short, symmetric shroud or duct that also acts as a structural outer-ring or support of the turbine rotor blades 150.
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FIG. 15A. is a frontal view of the alternate embodiment of the present invention shown in FIG. 15.
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FIG. 15B. is a frontal view of the alternate embodiment of the present invention shown in FIG. 15 utilizing turbine rotor and stator type blades.
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FIG. 16. is a side or top view of an alternate embodiment of the present invention. In this embodiment, the wake flow injector has an inlet 120 or source that is outside the primary and secondary (bypass) flow.
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FIG. 17. is a side view of an alternate embodiment of the present invention. In this embodiment, a turbine is shown with no shroud or duct and a single wake flow injector centered in the turbine or rotor blades. The wake flow injector has an inlet 20 just in front of the turbine blades, a pipe or tube 10 and an outlet 30 just behind the rotor in the wake flow area.
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FIG. 17A. is a frontal view of the alternate embodiment of the present invention shown in FIG. 17.
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FIG. 18. is a side view of an alternate embodiment of the present invention. In this embodiment, a turbine is shown with no shroud or duct and a single wake flow injector centered in the turbine or rotor blades. The wake flow injector has an inlet 20 just behind the turbine blades, a pipe or tube 10 and an outlet 30 just behind the rotor in the wake flow area.
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FIG. 18A. is a frontal view of the alternate embodiment of the present invention shown in FIG. 19.
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FIG. 19. is a perspective view of an alternate embodiment of the present invention. In this embodiment, a centered wake flow injector is deployed on a turbine with no shroud or duct as in FIG. 18. This embodiment also includes two wake flow injectors with inlets 20 in the bypass flow above and outside the diameter of turbine swept and outlets 30 inside the wake flow area behind the turbine blades.
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FIG. 20. is a frontal view of an alternate embodiment of the present invention. In this embodiment, a centered wake flow injector is deployed on a turbine with a shroud or duct having a squared opening on inlet.
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FIG. 21. is a frontal view of an alternate embodiment of the present invention. In this embodiment, a number of turbines of the type shown in FIG. 20 are deployed in a matrix layout all having the same frontal orientation into the direction of fluid or air flow and parallel axes of rotation. In this embodiment of the present invention, the matrix of turbines is deployed with a number of wake flow injectors of similar embodiment presented earlier in FIG. 1 through 19. In this embodiment, each turbine is shown with a center wake flow injector through the axis of rotation. In addition, the matrix is shown with a number of bypass wake flow injectors deployed around the periphery as well as in between the individual turbines.
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FIG. 21A. is a frontal view of an alternate embodiment of the present invention. In this embodiment, a number of turbines of the type shown n FIG. 20 are deployed in a matrix layout as shown in FIG. 21. In this embodiment of the present invention, the matrix is shown with a the bypass wake flow injectors deployed in between the individual turbines are shown as having square or non-circular inlets 10A and/or non-circular outlets 30A.
DETAILED DESCRIPTION OF THE INVENTION
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Referring now to the invention in more detail in FIG. 1 and FIG. 2, there is shown a turbine with a duct or shroud 40, a rotor or turbine blades 60 attached to a center axel of rotation 80, supported by stays or struts 70 that hold the axel and turbine in place. In addition, the present invention in FIG. 1 and FIG. 2 is shown with a duct, pipe or tube 10 having an inlet 20 and an outlet 30 with a crenulated trailing edge; this sub-assembly in this presented embodiment of the present invention is referred to as the wake flow injector.
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Referring now to the invention in more detail in FIG. 1 and FIG. 2, in FIG. 1, the fluid or air flow is from left to right. The fluid approaching directly in front of the shroud 40 opening is directed into the shroud and accelerated across the turbine rotor blades 60. The turbine rotor blades 60 extract energy from the flow through the shroud 40. The lower energy, slower moving fluid exits behind the rotor 60 and flows into the wake area downstream. The upstream fluid or air flow that is outside the area directly in front of the shroud 40 flows outside the shroud 40 on all sides. This flow outside the shroud 40 or turbine 60 is considered the bypass flow. The bypass flow directly in front of the inlet 20 for the bypass intake pipe 10 above and outside the shroud 40 enters the bypass tube or pipe 10. The fluid or air flow that enters the bypass tube or pipe 10 is directed down the pipe 10 and exits into the wake flow area via the outlet 30.
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The present invention of the embodiment presented in FIG. 1 and FIG. 2 should be deployed with sufficient distance from obstacles, obstructions, embankments or other turbines so as to allow for undisturbed bypass flow around the sides, top and/or bottom of the shroud—or turbine blades if no shroud or duct is employed.
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In the present invention of the embodiment presented in FIG. 1 and FIG. 2, the source of the bypass wake flow injector inlet 20 need not be from bypass flow outside or directly adjacent to the primary flow. The alternate embodiments of the present invention demonstrating this are presented below in FIG. 9 through FIG. 19 below.
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In the present invention of the embodiment presented in FIG. 1 and FIG. 2, the inlet 20 need not be round and the pipe or tube 10 and outlet 30 need not be of the same shape or diameter as other the other components of the wake flow ejector 10. Nor does the pipe or tube 10 need to be of the same shape or diameter from one end to the other. The shapes and diameters of the components are best determined by the particular application and/or embodiment of the present invention and the conditions under which it will operate. Similarly, the aerodynamic effects employed at the trailing edge of the outlet 30 need not be of a simple crenulated form.
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Referring now to the invention in more detail in FIG. 1 and FIG. 2, the materials used for the bypass wake flow ejector pipe 10 should be of sufficient stiffness to avoid structural failure and excessive vibration during expected operating conditions. Similarly, the material should also be of sufficient strength and have sufficient support to avoid warping or distortion of the pipe 10, the inlet 20 or outlet 30.
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The material used for the wake flow ejector pipe 10 should be relatively smooth along the inside diameter of the inlet 20, the pipe or tube 10 and the outlet 30 to minimize drag and turbulence of the bypass fluid or air flowing through the bypass wake flow injector.
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Referring now to the invention in more detail in FIG. 5, FIG. 6 and FIG. 7, there is shown four wake flow injectors with inlets 10, a pipe or tube for each 20 and an outlet 30 for each. In this embodiment, the bypass wake flow injectors are deployed on an open flow tidal turbine designed to extract energy from the flow of water into and out of an ocean tidal area. During alternating incoming and outgoing tidal flows, the flow of water is from right to left or left to right on the figure presented. There are two wake flow injectors deployed in each of the relevant flow directions. A simple flap or closing mechanism 90 is added to the outlet of each wake flow injector to prevent the reversing flow into the outlets of each wake flow injector during reverse flow periods.
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Referring now to the invention in more detail in FIG. 8 and FIG. 8A, there is shown an embodiment of the present invention similar to that of the primary embodiment shown in FIG. 1 and FIG. 2. In this embodiment, the outlet 30 is shared by both wake flow injectors with inlets 20. Both wake flow injectors share a common outlet 30 with a large diameter, crenulated trailing edge located at or near the center of the wake flow area behind the rotor or turbine blades.
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Referring now to the invention in more detail in FIG. 9 through FIG. 15B, there is shown a number of embodiments of the present invention that include a wake flow injector located along the center axis of the rotor or turbine blades. This center wake flow injector has an inlet 20 located in the area directly in front of the rotor turbine blades and a pipe or tube 10 that passes through the center axis or hub of the turbine and an outlet 30 behind the turbine in the wake flow area. In this embodiment, high energy flow is directed from an area directly in front of the swept area of the turbine rotor or blades and is passed through the center of the turbine and injected into the wake flow directly behind the rotor.
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Referring now to the invention in more detail in FIG. 16, there is shown an embodiment of the present invention similar to that of the primary embodiment shown in FIG. 1 and FIG. 2. In this embodiment the wake flow injector has an inlet 120 or source that is outside the primary and secondary (bypass) flow. The source of the bypass wake flow injector inlet 20 can be from a separate or outside source from the primary or bypass flows. This secondary, or outside source could include a nearby intersecting stream, rainwater nm-off, industrial or commercial water release, or in the case of a wind turbine, a nearby steam, blown cooling tower release or pressurized exhaust source.
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Referring now to the invention in more detail in FIG. 17 and FIG. 17A, there is shown an alternate embodiment of the present invention deployed on open flow hydro and wind turbines without ducts or shrouds. In FIG. 17 and FIG. 17A, the open flow hydro turbine has a large diameter center axel, hub or ring with a centered wake flow injector.
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Referring now to the invention in more detail in FIG. 18 and FIG. 18A, there is shown an alternate embodiment of the present invention deployed on traditional three bladed wind turbine without a duct or shroud. In this embodiment of the present invention, the turbine is deployed with a large diameter centered wake flow injector with an inlet 20 that is directly behind the rotor turbine blades, a short tube or pipe 10 and an outlet 30 that is inside the wake flow area down stream.
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Referring now to the invention in more detail in FIG. 19, there is shown a perspective view of the embodiment of the present invention shown in FIG. 18 and FIG. 18A and includes an additional two bypass wake flow injectors; one with intake 20 in the upper left area of the bypass flow outside the primary flow area, and one with intake 20 in the upper right area of the bypass flow outside the primary flow area.
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Referring now to the invention in more detail in FIG. 21, in this embodiment of the present invention, a number of turbines of the type shown in FIG. 20 are deployed in a matrix layout all having the same frontal orientation into the direction of fluid or air flow and parallel axes of rotation. In this embodiment of the present invention, the matrix of turbines is deployed with a number of wake flow injectors of similar embodiment presented earlier in FIG. 1 through 19. In this embodiment, each turbine is shown with a center wake flow injector through the axis of rotation. In addition, the matrix is shown with a number of bypass wake flow injectors deployed around the periphery as well as in between the individual turbines.
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While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiments, methods, and examples, but by all embodiments and methods within the scope and spirit of the invention as claimed.
