Abstract:
A system for improved power generation through movement of water having a turbine with a generally cylindrical housing, where the turbine is positioned to receive kinetic energy from moving water, and a member positioned circumferentially about the housing for inducing a pressure drop across the turbine. The member may be a rotating blade, cantilevered duct, circumferential flange, radial eductor, and air tube for injection of ambient air into said water source.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is based on provisional application Ser. No. 60/920,255, filed on Mar. 27, 2007, which is incorporated as if fully set forth herein. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]    Not Applicable 
       DESCRIPTION OF ATTACHED APPENDIX  
       [0003]    Not Applicable 
       BACKGROUND OF THE INVENTION  
       [0004]    This invention relates generally to the field of hydroelectric power and more specifically to a system and apparatus for improved turbine pressure and pressure drop control. 
         [0005]    There are a variety of prior art systems for increasing power through conventional turbines. None of these patents shows the innovative combination of the present invention and its use of various enhancements to control pressure drop at the rotating turbine. This invention works with both horizontal and vertical axis hydrokinetic turbines. 
       BRIEF SUMMARY OF THE INVENTION  
       [0006]    The primary advantage of the invention is to provide improved turbine throughput from higher velocity than ambient conditions. 
         [0007]    Another advantage of the invention is to provide improved enhancements to turbine flow properties. 
         [0008]    Another advantage of the invention is to provide eductors or ejectors to enhance turbine flow characteristics. 
         [0009]    Another advantage of the invention is to provide counter rotating members to enhance turbine flow characteristics. 
         [0010]    Another advantage of the invention is to efficiently increase velocity through a turbine and have the greatest impact on power output. 
         [0011]    The present invention accomplishes the foregoing objects by incorporating in a hydrokinetic turbine installation a variety of mechanisms and devices to modify water flow and increase the pressure drop between the inducted water flow and the outflow across a hydrokinetic turbine, thus increasing water velocity and hence increase energy produced by the hydrokinetic turbine installation. 
         [0012]    In accordance with a preferred embodiment of the invention, there is shown a system for improved power generation through movement of water having a turbine with a generally cylindrical housing (also called a runner), where the turbine is positioned to receive kinetic energy from moving water, and has a member positioned circumferentially about the runner for inducing a pressure drop, swirl or vortex across the turbine 
         [0013]    Other objects and advantages of the present invention will become apparent from the following descriptions, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0014]    The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention. 
           [0015]      FIG. 1A  shows a side cross sectional view of a stationary or rotating exterior blade mounted on a turbine in accordance with a preferred embodiment of the invention.  FIG. 1B  shows a longitudinal elevation view of  FIG. 1A . 
           [0016]      FIG. 2A  shows a side cross sectional view of a cantilevered system in front of or behind the turbine unit in accordance with a preferred embodiment of the present invention.  FIG. 2B  shows a longitudinal elevation view of  FIG. 2A . 
           [0017]      FIG. 3A  shows a cross sectional view of a circumferential fixed flange about a turbine that creates turbulence in accordance with a preferred embodiment of the present invention.  FIG. 3B  shows a longitudinal elevation view of  FIG. 3A . 
           [0018]      FIG. 4A  shows a side cross sectional view of a radial eductor positioned about the circumference of the turbine housing to create turbulence in accordance with a preferred embodiment of the present invention.  FIG. 4B  shows a longitudinal elevation view of  FIG. 4A . 
           [0019]      FIG. 5A  shows a side cross sectional view of a turbine having an air inlet that directs into the stream of flow through the input side of the turbine in accordance with a preferred embodiment of the present invention.  FIG. 5B  shows a longitudinal elevation view of  FIG. 5A . 
           [0020]      FIG. 6A  shows a cross sectional view of a front ejector about the circumference of the turbine housing in accordance with a preferred embodiment of the invention. 
           [0021]      FIG. 6B  shows a cross sectional view of a rear ejector about the circumference of the turbine housing in accordance with a preferred embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]    Detailed descriptions of the preferred embodiment are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner. 
         [0023]    In accordance with a preferred embodiment of the invention, there is disclosed a method to control pressure drop for current based hydro kinetic devices for generating power in stand alone or array based structures in ocean currents, tidal currents, river currents, canals, conduits, and aqueducts that significantly enhance power generation versus non ducted and simple ducted (single or double) devices. Within those structures the primary objective to increase power output in a hydrokinetic current based system is by controlling pressure drop across the whole device or specifically sections/areas of the device. By controlling pressure drop one can increase velocity relative to the ambient velocity which has the highest impact on increased power output. 
         [0024]    This can be done in a number of ways according to the invention. Aerofoils (hydrofoils) around the rotating turbine, slip streams, nested sets of ducts, or bubbling upstream or downstream components which may or may not rotate to modify pressure drop (velocity) at the rotating turbine will achieve some of the benefits of the present invention. Alternatively, one can use eductors, ejectors or counter rotating members to enhance velocity and thus increase power. In yet another embodiment, a nested set of counter rotating elements can also help increase velocity both in axial shaft and shaftless (circumferential generator) also called permanent magnet or magnetically levitated designs. 
         [0025]    In its operation, the hydrokinetic turbine installation of the present invention converts the kinetic energy in a current into usable power. Traditional hydroelectric turbine/generator systems installed using dammed water sources convert potential energy into usable power. More particularly, water flow from undammed sources that has the water flow characteristics modified, i.e. water flow pressure drop is modified to increase velocity across a hydrokinetic turbine installation to increase energy production further. The present invention can also be applied at an existing hydroelectric facility. 
         [0026]    The present invention deals specifically with provisions for a stationary or rotating or counterrotating exterior blade about a hydrokinetic turbine to increase the pressure drop across the turbine, the desired result being that the turbine is enabled to operate using higher water velocity relative to the ambient, substantially increasing power production and enabling individual elements operating near the modes of their peak efficiencies. 
         [0027]    Turning now to  FIG. 1A , there is shown in side cross section a stationary or rotating exterior blade  10  circumferentially mounted on housing  16  about turbine  12 . Blade  10  induces a swirl or vortex that increases flow across the turbine  12 , thereby increasing velocity of water  14  across turbine  12  as the water pressure drop increases. Blade  10  may also be counter rotating depending on the flow characteristics that are desired.  FIG. 1B  shows a cross sectional longitudinal view of the system where blade  10  may also be fixed but positioned in such a way as to lower pressure on the output side and create turbulence, swirl, a vortex or other flow features further increasing velocity. As blade  10  rotates, a pressure drop is achieved around turbine  12  thus increasing velocity  14  through turbine  12 . Blade  10  can also be fixed, acting like vanes to induce a vortex which can increase velocity  14  and thus power output. 
         [0028]      FIG. 2A  shows a side cross section of a cantilevered system  20  for guiding water flow behind turbine  26  and turbine unit housing  22 .  FIG. 2B  shows a longitudinal front view of the same system is shown on the front side of turbine  26 . In either configuration with the cantilevered system being placed in front of or behind the turbine  26 , the added duct  24  operates to increase velocity  28  through turbine  26  and achieve the benefits of the present invention. In an alternative preferred embodiment the water flow and velocity  28  is reversed with cantilevered system  20  and duct  24  guiding the water flow into turbine  26 . The position of the cantilevered system  20  can be such that the vertical cross section of the end of the cantilevered system  20  is in front or behind the vertical cross section of the end of the duct/housing  22  relative to the direction of flow. In another embodiment, the vertical cross section of the end of the cantilevered system  20  can be inside the vertical cross section of the end of the duct/housing  22  relative to the direction of flow. 
         [0029]      FIG. 3A  shows a circumferential fixed flange  30  with an angle relative to the horizontal housing greater than 20 degrees about turbine  36  that creates turbulence  32  and thus pressure drop which in turn enhances velocity through turbine  36  and increases power output.  FIG. 3B  shows a cross sectional longitudinal view of turbine  36  turbine housing  34  and flange  30 . In an alternative preferred embodiment, flange  30  may also have freedom of movement for rotation  38  either clockwise or counterclockwise about turbine  36 . 
         [0030]      FIG. 4A  shows a side cross section view of a radial eductor  40  positioned about the circumference of turbine housing  42  to create and control pressure drops thus increasing velocity  49  and thereby increasing power output.  FIG. 4B  shows a cross sectional longitudinal view of radial eductor  40  which has an opening inlet  44  on input side of turbine  48  and an exit outlet  46  on the output side of turbine  48  and turbine housing  42 . 
         [0031]      FIG. 5A  shows a side cross sectional view of turbine  58  and turbine housing  56  having an air tube system comprising an air tube  50 , air inlet  52  and air outlet  59  that directs air into the water flow through the input side of the turbine  58  to affect the flow characteristics of turbine  58  and increase velocity  52 .  FIG. 5B  shows a cross sectional longitudinal view of turbine  54  with air inlet  56  to direct air into the water flow to increase velocity  68  and thus energy for extraction by turbine  54 . 
         [0032]      FIG. 6A  shows in a cross sectional view a front ejector  60  about the circumference of turbine housing  62  and turbine  64  to decrease pressure across turbine blade  64  and thus increase velocity  68  and power output. 
         [0033]      FIG. 6B  show in a cross sectional view a rear ejector  66  about turbine  64  and the circumference of turbine housing  68 , rear ejector  66  injecting water flow to decrease pressure across turbine blade  69  and thus increase velocity and power output. 
         [0034]    While the invention has been described in connection with several preferred embodiments, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the claims.