Fluid turbines

Abstract

Shrouded fluid turbines of various configurations are disclosed. The shrouded fluid turbines include an impeller, a turbine shroud surrounding the impeller, and an ejector shroud around the turbine shroud. The ejector shroud may completely surround the turbine shroud. The turbine shroud may have a plurality of mixing lobes that form a crenellated trailing edge. Alternatively, the turbine shroud may have a plurality of open slots. Means for directing fluid flow into the plurality of open slots may include an ejector shroud that seals with the turbine shroud downstream of the open slots. A plurality of fluid ducts may also connect individually to each open slot. An external stator may be connected to an exterior surface of the ejector shroud.

1 . A fluid turbine comprising:
 an impeller;   a turbine shroud surrounding the impeller, the turbine shroud comprising a leading edge and a plurality of mixing lobes that form a crenellated trailing edge, the trailing edge having a first diameter; and   an ejector shroud coaxial with the turbine shroud, the ejector shroud comprising a leading edge and a trailing edge, the leading edge having a second diameter, wherein the second diameter is greater than the first diameter.   
     
     
         2 . The fluid turbine of  claim 1 , wherein the leading edge of the turbine shroud is coplanar with the leading edge of the ejector shroud. 
     
     
         3 . The fluid turbine of  claim 1 , wherein the leading edge of the turbine shroud is downstream of the leading edge of the ejector shroud. 
     
     
         4 . The fluid turbine of  claim 1 , wherein the leading edge of the turbine shroud has a substantially circular shape. 
     
     
         5 . The fluid turbine of  claim 1 , wherein the leading edge of the ejector shroud has a substantially circular shape. 
     
     
         6 . The fluid turbine of  claim 1 , wherein the ejector shroud has a ring airfoil shape. 
     
     
         7 . The fluid turbine of  claim 1 , further comprising a nacelle body, the impeller surrounding the nacelle body, the nacelle body having a trailing edge, wherein the nacelle body, turbine shroud, and ejector shroud are coaxial to each other. 
     
     
         8 . The fluid turbine of  claim 7 , wherein the trailing edge of the nacelle body is upstream of the trailing edge of the ejector shroud. 
     
     
         9 . The fluid turbine of  claim 7 , wherein the trailing edge of the nacelle body is downstream of the trailing edge of the ejector shroud. 
     
     
         10 . The fluid turbine of  claim 1 , wherein the impeller is a rotor/stator assembly. 
     
     
         11 . A fluid turbine comprising:
 an impeller;   a turbine shroud surrounding the impeller, the turbine shroud comprising a plurality of open slots downstream of the impeller; and   an exterior structure for directing fluid flow from outside the turbine shroud through the plurality of open slots.   
     
     
         12 . The fluid turbine of  claim 11 , wherein the exterior structure for directing fluid flow is an ejector shroud disposed about the turbine shroud, the turbine shroud and the ejector shroud being sealed to each other downstream of the plurality of open slots. 
     
     
         13 . The fluid turbine of  claim 11 , wherein the exterior structure for directing fluid flow is a plurality of fluid ducts located along an exterior surface of the turbine shroud, each fluid duct comprising an inlet and an outlet, the outlet being connected to one of the opens slot in the turbine shroud. 
     
     
         14 . The fluid turbine of  claim 13 , wherein each fluid duct further comprises a fluid duct impeller. 
     
     
         15 . The fluid turbine of  claim 13 , wherein the inlets of the plurality of fluid ducts are downstream of an inlet end of the turbine shroud and are parallel to the inlet end of the turbine shroud. 
     
     
         16 . The fluid turbine of  claim 11 , wherein a leading edge of the turbine shroud has a substantially circular shape. 
     
     
         17 . A fluid turbine comprising:
 an impeller;   a turbine shroud surrounding the impeller;   an ejector shroud downstream of the turbine shroud, a trailing edge of the turbine shroud extending into an inlet end of the ejector shroud; and   a stator connected to an exterior surface of the ejector shroud.   
     
     
         18 . The fluid turbine of  claim 17 , wherein the turbine shroud comprises a substantially circular leading edge and a plurality of mixing lobes that form a crenellated trailing edge. 
     
     
         19 . The fluid turbine of  claim 17 , wherein the stator has a ring airfoil shape. 
     
     
         20 . The fluid turbine of  claim 17 , wherein the ejector shroud has a ring airfoil shape. 
     
     
         21 . A fluid turbine comprising:
 an impeller;   a turbine shroud surrounding the impeller, the turbine shroud comprising a leading edge and a plurality of mixing lobes that form a crenellated trailing edge; and   an ejector shroud completely surrounding the turbine shroud, the ejector shroud comprising a leading edge and a trailing edge.