Underwater ducted turbine

Abstract

An apparatus is disclosed for a turbine for generating electrical power from water or air flow comprising at least one rotor disk having a plurality of hydrofoil blades, guide vanes, a cylindrical housing, and a generator means. A rim generator comprising a magnet race rotor rim and fixed stator coils in the housing is used. The apparatus is fitted with a screen to stop the ingress of debris and marine life, and a skirt augmenter device to reduce the Betz effect. The apparatus is preferably for sub-sea deployment and driven by tidal currents, but may be powered by river current or wave driven air or by wind. The apparatus may be deployed on at least one telescoping pole, tethered to the sea-bed and kept buoyant by buoyant concrete in the housing, or inserted in a darn, under a barge or in a tidal power array.

1 . A hydro turbine generator apparatus for generating electrical power from water flow, said apparatus comprising at least one magnetic generator and characterized by:
 (a) at least one rotor disk comprising a plurality of blades rotatable about a central axis;   (b) a generally cylindrical housing defining a duct, said duct being proximate to the tips of said blades; and   (c) wherein said at least one magnetic generator is unsealed.   
     
     
         2 . The apparatus according to  claim 1 , wherein at least one of: said tips of said blades and roots of said blades located distally from said tips, are attached to a rotor rim. 
     
     
         3 . The apparatus according to  claim 1  wherein said blades are symmetric in cross section. 
     
     
         4 . The apparatus according to  claim 2  wherein said rotor rim is attached to said roots of said blades, and is substantially annular and defines a hole located substantially in the center of said rotor disk. 
     
     
         5 . The apparatus according to  claim 1  wherein said rotor rim defines a hub, and wherein said unsealed magnetic generator is disposed in at least one of said rotor rim, said duct, and said hub. 
     
     
         6 . The apparatus according to  claim 5  further comprising a bypass hole defined by said hub such that a portion of said water flow passes longitudinally through said hub. 
     
     
         7 . The apparatus according to  claim 1 , wherein said unsealed magnetic generator is flooded with ambient fluid. 
     
     
         8 . The apparatus according to  claim 2  wherein said rotor rim is attached to said roots of said blades, and defines a hub, and wherein said unsealed magnetic generator comprises:
 one or more magnets disposed in at least one of: said roots of said blades and said rotor rim; and   one or more stator coils disposed in said hub.   
     
     
         9 . The apparatus according to  claim 1  wherein said unsealed magnetic rim generator is at least one of: a dual or single axial flux generator, and a dual or single radial flux generator. 
     
     
         10 . The apparatus according to  claim 1  wherein said hydro turbine generator is bi-directional and can accept said water flow from either of two open ends of said housing for the generation of electrical power. 
     
     
         11 . The apparatus according to  claim 1  further comprising an augmentor disposed on or about an outer surface of, or integrated with said duct. 
     
     
         12 . The apparatus according to  claim 1  wherein said duct has a converging inner surface such that a venturi effect is created. 
     
     
         13 . The apparatus according to  claim 1  wherein one or more of: at least one said rotor disk and at least one said unsealed magnetic generator, are adapted to be removed as a modular unit or cassette. 
     
     
         14 . The apparatus according to  claim 1  further comprising a first rotor disk and a second rotor disk, said first rotor disk being upstream and rotating in a first direction to the water flow and said second rotor disk being downstream and counter-rotating in relation to said first rotor disk in a second direction to the water flow. 
     
     
         15 . The apparatus according to  claim 5 , further comprising one or more magnetic bearings situated between said rotor disk and at least one of said duct, housing and hub. 
     
     
         16 . A hydro turbine generator apparatus for generating electrical power from water flow, said apparatus comprising at least one magnetic generator and characterized by:
 (a) at least one rotor disk comprising a rotor rim and a plurality of blades attached to said rotor rim;   (b) a generally cylindrical housing defining a duct, said duct being proximate to the tips of said blades; and   (c) wherein said at least one magnetic generator is a flooded magnetic generator.   
     
     
         17 . The apparatus according to  claim 16  wherein said rotor rim defines a hub, and wherein said flooded magnetic generator is disposed in at least one of said rotor rim, said duct, and said hub. 
     
     
         18 . The apparatus according to  claim 16  wherein said rotor rim defines a hub, and wherein said flooded magnetic rim generator comprises one or more stator coils disposed in said hub, and one or more magnets disposed at one or more of: the roots of said blades located distal to said tips of said blades, and said rotor rim. 
     
     
         19 . A method of installing a hydro turbine generator apparatus comprising a generally cylindrical housing, at least one rotor disk and an unsealed magnetic generator, the method comprising:
 installing a foundation structure on the bottom of a body of water, wherein said foundation structure comprises mounting means;   attaching the housing of said hydro turbine generator apparatus to said foundation structure using said mounting means.   
     
     
         20 . The method according to  claim 20  additionally comprising installing one or more of: said at least one rotor disk, and said unsealed magnetic generator, into said housing of said hydro turbine generator apparatus as a modular unit or cassette.