Turbomachinery Having Self-Articulating Blades, Shutter Valve, Partial-Admission Shutters, and/or Variable-Pitch Inlet Nozzles

Abstract

An axial-flow turbine assembly that includes one or more features for enhancing the efficiency of the turbine's operation. In one embodiment, the turbine assembly includes a turbine rotor having blades that adjust their pitch angle in direct response to working fluid pressure on the blades themselves or other part(s) of the rotor. In other embodiments, the turbine assembly is deployable in an application, such as an oscillating water column system, in which the flow of working fluid varies over time, for example, as pressure driving the flow changes. In a first of these embodiments, the turbine assembly includes a valve that allows the pressure to build so that the flow is optimized for the turbine's operating parameters. In a second of these embodiments, one or more variable-admission nozzle and shutter assemblies are provided to control the flow through the turbine to optimize the flow relative to the turbine's operating parameters.

What is claimed is: 
     
         1 . An oscillating water column (OWC) system, comprising:
 a structure containing an air-water chamber designed and configured to receive water waves in a manner that changes the volume of air within said air-water chamber during operation, wherein said structure includes an opening between said air-water chamber and an air environment outside said chamber when said structure is deployed;   an air-turbine mounted in said opening and designed and configured to be driven by air flowing through said opening during operation of the OWC system;   a valve located in said opening and designed and configured to modulate the flow of air through said air-turbine during operation of the OWC system; and   a control system designed and configured to modulate said valve in a manner that allows pressure within said air-water chamber to build to a predetermined magnitude before opening said valve.   
     
     
         2 . An OWC system according to  claim 1 , wherein said valve is a shutter valve having pivotable blades, and the OWC system further comprises an actuation mechanism that is responsive to said control system and is designed and configured to pivot said pivotable blades between open positions and closed positions. 
     
     
         3 . An OWC system according to  claim 2 , wherein said air-turbine includes a rotor having a plurality of blades disposed in a first annular region within said opening, and said pivotable blades of said shutter valve are arranged in a second annular region similar in size to said first annular region but spaced from said first annular region. 
     
     
         4 . An OWC system according to  claim 3 , wherein said plurality of blades of said rotor are self-articulating in response to pressure of air on said rotor, and said control system is designed and configured to pivot said pivotable blades of said shutter valve in coordination with the self-articulation of said plurality of blades of said rotor. 
     
     
         5 . A partial-admission axial-flow turbine assembly, comprising:
 a first annular working-fluid flow region;   a turbine-rotor having a plurality of blades located in said first annular working-fluid flow region; and   a first nozzle and shutter assembly having a second annular working-fluid flow region spaced from said first annular working-fluid flow region and including:
 a first plurality of articulatable nozzle blades disposed in a first portion of said second annular working-fluid flow region; and 
 a first plurality of articulatable shutter blades disposed in a second portion of said second annular working-fluid flow region. 
   
     
     
         6 . A partial-admission axial-flow turbine assembly according to  claim 5 , wherein said first plurality of articulatable shutter blades are self articulating in direct response to flow of working fluid through said second annular working-fluid flow region. 
     
     
         7 . A partial-admission axial-flow turbine assembly according to  claim 5 , wherein said first plurality of articulatable nozzle blades are designed and configured to provide nozzling for working fluid flow from a first direction and said first plurality of articulatable shutter blades are designed and configured to be closed when working fluid flow is from the first direction and open when working fluid flow is from a second direction opposite the first direction. 
     
     
         8 . A partial-admission axial-flow turbine assembly according to  claim 5 , wherein said first plurality of articulatable nozzle blades are arranged into groupings that are separately controllable relative to blade pitch. 
     
     
         9 . A partial-admission axial-flow turbine assembly according to  claim 8 , wherein said groupings are arranged by sectors. 
     
     
         10 . A partial-admission axial-flow turbine assembly according to  claim 9 , each of said groupings has a corresponding blade-pitch actuator designed and configured to pivot only the ones of said first plurality of articulatable nozzle blades in that one of said groupings. 
     
     
         11 . A partial-admission axial-flow turbine assembly according to  claim 10 , further comprising a control system operatively configured to control each said blade-pitch actuator as a function of the rotational speed of said turbine rotor and the flow rate of working fluid into the partial-admission axial-flow turbine assembly. 
     
     
         12 . A partial-admission axial-flow turbine assembly according to  claim 5 , further comprising a second nozzle and shutter assembly having a third annular working-fluid flow region spaced from said first annular working-fluid flow region on a side of said first annular working-fluid flow region opposite said second annular working-fluid flow region, said second nozzle and shutter assembly including:
 a second plurality of articulatable nozzle blades disposed in a first portion of said third annular working-fluid flow region; and   a second plurality of articulatable shutter blades disposed in a second portion of said third annular working-fluid flow region.   
     
     
         13 . A partial-admission axial-flow turbine assembly according to  claim 12 , wherein said first portion of said second plurality of articulatable nozzle blades are located opposite said first plurality of articulatable shutter blades and said second plurality of articulatable shutter blades are located opposite said first plurality of articulatable shutter blades. 
     
     
         14 . A partial-admission axial-flow turbine assembly according to  claim 13 , wherein said first plurality of articulatable shutter blades are designed and configured to be open when working fluid is flowing in a first direction and said second plurality of articulatable shutter blades are designed and configured to be closed when working fluid is flowing in the first direction. 
     
     
         15 . A method of optimizing efficiency of an air-turbine in an oscillating water column (OWC) system, wherein the air-turbine is designed for an optimal air flow, comprising:
 providing a valve designed and configured to control flow of air through the air-turbine;   monitoring at least one condition inside an air-water chamber of the OWC system; and   modulating the valve as a function of the at least one condition in a manner that maximizes the time that the air-turbine receives the optimal air flow.   
     
     
         16 . A method according to  claim 15 , wherein said providing a valve includes providing a shutter valve having shutter blades, and said modulating the valve includes pivoting the shutter blades between open and closed positions. 
     
     
         17 . A method according to  claim 15 , wherein said monitoring at least one condition includes monitoring air pressure within the air-water chamber.