Fluid turbine with vortex generators

Abstract

The present disclosure relates to fluid turbines having a turbine shroud assembly formed with mixing elements (e.g., both inwardly and outwardly curving elements) having airfoil cross sections. These airfoils form ringed airfoil shapes that provide a means of controlling the flow of fluid over the rotor assembly or over portions of the rotor assembly. The fluid dynamic performance of the ringed airfoils directly affects the performance of the turbine rotor assembly. The mass and surface area of the shrouds result in load forces on support structures. By delaying or eliminating the separation of the boundary layer over the ringed airfoils, boundary layer energizing members (e.g., vortex generators, flow control ports) on the ringed airfoils increase the power output of the fluid turbine system and allow for relatively shorter chord-length airfoil cross sections and therefore reduced mass and surface area of the shroud assemblies.

What is claimed is: 
     
         1 . A shrouded fluid turbine system comprising:
 a rotor assembly;   a turbine shroud assembly disposed about the rotor assembly, the turbine shroud having a low pressure side and a high pressure side, the low pressure side in fluid communication with the rotor assembly; and   at least one boundary layer energizing member associated with the turbine shroud assembly, the at least one boundary layer energizing member configured and dimensioned to alter a fluid boundary layer over a surface of the turbine shroud assembly to alter the performance of the fluid turbine system.   
     
     
         2 . The system of  claim 1 , wherein the at least one boundary layer energizing member is positioned proximal to a leading edge of the turbine shroud assembly. 
     
     
         3 . The system of  claim 1  further comprising a first plurality of boundary layer energizing members and a second plurality of boundary layer energizing members;
 wherein the first plurality of boundary layer energizing members are positioned proximal to a leading edge of the turbine shroud assembly; and 
 wherein the second plurality of boundary layer energizing members are positioned between the leading edge and a trailing edge of the turbine shroud assembly. 
 
     
     
         4 . The system of  claim 3 , wherein the first and second pluralities of boundary layer energizing members are associated with the low pressure side of the turbine shroud assembly. 
     
     
         5 . The system of  claim 1  further comprising a plurality of boundary layer energizing members;
 wherein the turbine shroud assembly includes a plurality of curving mixing elements; and 
 wherein each mixing element is associated with at least one boundary layer energizing member. 
 
     
     
         6 . The system of  claim 5 , wherein the plurality of curving mixing elements includes a first plurality of inwardly curving mixing elements and a second plurality of outwardly curving mixing elements. 
     
     
         7 . The system of  claim 6 , wherein at least one boundary layer energizing member is positioned on the high pressure side of the turbine shroud assembly and proximal to an inward curving mixing element of the plurality of inward curving mixing elements. 
     
     
         8 . The system of  claim 1 , wherein the turbine shroud assembly defines an airfoil ring having an apex; and
 wherein the at least one boundary layer energizing member is positioned proximal to the apex of the airfoil ring.   
     
     
         9 . The system of  claim 1 , wherein the at least one boundary layer energizing member is a vortex generator, the vortex generator in the form of a protruding member that protrudes from a surface of the turbine shroud assembly. 
     
     
         10 . The system of  claim 9 , wherein the vortex generator has a length and a height; and
 wherein the length is about four times the height of the vortex generator.   
     
     
         11 . The system of  claim 9 , wherein the vortex generator has a length and a height;
 wherein the vortex generator is fabricated from a flexible material and includes a first un-flexed condition and a second flexed condition; and   wherein when the vortex generator is in the second flexed condition, the length of the vortex generator is about eight times the height.   
     
     
         12 . The system of  claim 5 , wherein each curving mixing element includes a voluminous leading edge that transitions to a curved planar form at a trailing edge. 
     
     
         13 . The system of  claim 1  further comprising an ejector shroud assembly positioned downstream from and coaxial with the turbine shroud assembly;
 wherein at least one boundary layer energizing member is associated with the ejector shroud assembly, the at least one boundary layer energizing member associated with the ejector shroud assembly configured and dimensioned to alter a fluid boundary layer over a surface of the ejector shroud assembly to alter the performance of the fluid turbine system. 
 
     
     
         14 . The system of  claim 13 , wherein the at least one boundary layer energizing member associated with the ejector shroud assembly is positioned proximal to a leading edge of the ejector shroud assembly. 
     
     
         15 . The system of  claim 13  further comprising a first plurality of boundary layer energizing members and a second plurality of boundary layer energizing members associated with the ejector shroud assembly;
 wherein the first plurality of boundary layer energizing members are positioned proximal to a leading edge of the ejector shroud assembly; and 
 wherein the second plurality of boundary layer energizing members are positioned between the leading edge and a trailing edge of the ejector shroud assembly. 
 
     
     
         16 . The system of  claim 15 , wherein the first and second pluralities of boundary layer energizing members are associated with the low pressure side of the ejector shroud assembly. 
     
     
         17 . The system of  claim 13 , wherein the ejector shroud assembly defines an airfoil ring having an apex; and
 wherein the at least one boundary layer energizing member associated with the ejector shroud assembly is positioned proximal to the apex of the airfoil ring.   
     
     
         18 . The system of  claim 13 , wherein the at least one boundary layer energizing member associated with the ejector shroud assembly is a vortex generator, the vortex generator in the form of a protruding member that protrudes from a surface of the ejector shroud assembly. 
     
     
         19 . The system of  claim 1 , wherein the at least one boundary layer energizing member is a flow control port, the flow control port configured and dimensioned to employ high velocity flow through the flow control port for flow control purposes and to alter a fluid boundary layer over a surface of the turbine shroud assembly to alter the performance of the fluid turbine system. 
     
     
         20 . The system of  claim 19 , wherein the at least one flow control port is positioned proximal to a leading edge of the turbine shroud assembly. 
     
     
         21 . The system of  claim 19 , wherein the at least one flow control port is remotely energized with the high velocity flow. 
     
     
         22 . The system of  claim 19 , wherein the at least one flow control port is energized with the high velocity flow by harvesting fluid energy from the fluid turbine system. 
     
     
         23 . The system of  claim 1 , wherein the at least one boundary layer energizing member is configured and dimensioned to prevent separation of a fluid boundary layer over a surface of the turbine shroud assembly to alter the performance of the fluid turbine system. 
     
     
         24 . The system of  claim 1 , wherein the at least one boundary layer energizing member is configured and dimensioned to alter a fluid boundary layer over a surface of the turbine shroud assembly to reduce the performance of the fluid turbine system. 
     
     
         25 . The system of  claim 1 , wherein the turbine shroud assembly defines an annular airfoil having a leading edge that transitions to a faceted trailing edge. 
     
     
         26 . The system of  claim 19 , wherein the volume or angle of the high velocity flow through the flow control port is variable. 
     
     
         27 . The system of  claim 1 , wherein the at least one boundary layer energizing member configured and dimensioned to alter a fluid boundary layer over a surface of the turbine shroud assembly alters the performance of the fluid turbine system. 
     
     
         28 . A shrouded fluid turbine system comprising:
 a rotor assembly;   a turbine shroud assembly disposed about the rotor assembly, the turbine shroud having a low pressure side and a high pressure side, the low pressure side in fluid communication with the rotor assembly, the turbine shroud assembly including a plurality of curving mixing elements; and   a first and second plurality of boundary layer energizing members associated with the turbine shroud assembly, each boundary layer energizing member configured and dimensioned to alter a fluid boundary layer over a surface of the turbine shroud assembly, the first plurality of boundary layer energizing members positioned proximal to a leading edge of the turbine shroud assembly and the second plurality of boundary layer energizing members positioned between the leading edge and a trailing edge of the turbine shroud assembly, at least a portion of the first and second pluralities of boundary layer energizing members associated with the low pressure side of the turbine shroud assembly, and each mixing element associated with at least one boundary layer energizing member.   
     
     
         29 . A shrouded fluid turbine system comprising:
 a rotor assembly;   a turbine shroud assembly disposed about the rotor assembly, the turbine shroud having a low pressure side and a high pressure side, the low pressure side in fluid communication with the rotor assembly;   at least one first boundary layer energizing member associated with the turbine shroud assembly, the at least one first boundary layer energizing member configured and dimensioned to alter a fluid boundary layer over a surface of the turbine shroud assembly to alter the performance of the fluid turbine system;   an ejector shroud assembly positioned downstream from and coaxial with the turbine shroud assembly;   at least one second boundary layer energizing member associated with the ejector shroud assembly, the at least one second boundary layer energizing member configured and dimensioned to alter a fluid boundary layer over a surface of the ejector shroud assembly to alter the performance of the fluid turbine system;   wherein the turbine shroud assembly includes a plurality of curving mixing elements;   wherein the at least one first boundary layer energizing member is positioned proximal to a leading edge of the turbine shroud assembly; and   wherein the at least one second boundary layer energizing member is positioned proximal to a leading edge of the ejector shroud assembly.