Wind turbine diffuser

Abstract

The invention concerns a diffuser for a whine turbine, in particular a large-dimension wind turbine mounted on a mast ( 2 ) and comprising a wind-driven propeller ( 3 ) equipped with blades ( 4 ) as well as an alternator converting wind kinetic energy into electric, power. The invention is characterized in that it consists of a circular element ( 7 ) enclosing the ends ( 9 ) of the blades ( 5 ), and consisting of a skin ( 14 ) made of a stretched textile membrane associated with a rigid internal and/or external framework ( 15 ) supporting the loads and enabling to stretch the membrane and forming it.

1 . Diffuser for a wind turbine, in particular a wind turbine of large dimensions mounted on a mast ( 2 ) and having a wind-driven propeller ( 3 ) fitted with blades ( 5 ) and an alternator for converting kinetic wind energy into electricity, characterised in that it comprises a circular element ( 7 ) surrounding the ends ( 9 ) of the blades ( 5 ) and comprising a skin ( 14 ) in the form of a stretched textile membrane in conjunction with a rigid internal and/or external framework ( 15 ) supporting load and enabling the membrane to be kept taut and impart the requisite shape to it.  
   
   
       2 . Diffuser as claimed in  claim 1 , characterised in that the textile membrane ( 14 ) has a density in the order of 1 kg/dm 3 .  
   
   
       3 . Diffuser as claimed in  claim 1 , characterised in that the textile membrane ( 14 ) is provided with a lagging enabling it to be reinforced, in particular in its zone located in proximity to the blades ( 5 ).  
   
   
       4 . Diffuser as claimed in  claim 1 , characterised in that the rigid framework ( 15 ) comprises a series of identical radiating ribs ( 16 ), intrinsically closed and having a planar curve with a wing-shaped contour corresponding to the contour of the diffuser ( 7 ) and constituting the internal surface ( 18 ) and external surface ( 19 ) thereof.  
   
   
       5 . Diffuser as claimed in  claim 4 , characterised in that the rigid framework ( 15 ) comprises: 
 a series of peripheral members ( 17 ) enabling the radiating ribs ( 16 ) to be linked and, if necessary, a series of stiffening elements enabling the thickness of the contour of the diffuser ( 7 ) to be kept constant.    
   
   
       6 . Diffuser as claimed in  claim 5 , characterised in that the radiating ribs ( 16   1 ) and the peripheral members ( 17   1 ) are steel tubes.  
   
   
       7 . Diffuser as claimed in  claim 5 , characterised in that the radiating ribs ( 16   2 ) are provided in the form of aluminium sections with a cross-section with a a shape, whilst the peripheral members ( 17   2 ) are aluminium tubes.  
   
   
       8 . Diffuser as claimed in  claim 5 , characterised in that the radiating ribs ( 16   3 ) are provided in the form of timber sections which are T-shaped in particular, and the peripheral members ( 17   3 ) are carbon beams, in particular with a rectangular cross-section, linked in pairs by cores ( 24 ) in particular of plywood, on either side of the radiating ribs ( 16   3 ) so as to define box-type spars.  
   
   
       9 . Diffuser as claimed in  claim 8 , characterised in that the box-type spars have cut-outs ( 25 ) at their median part.  
   
   
       10 . Diffuser as claimed in  claim 5 , characterised in that the radiating ribs ( 16   4 ) are provided in the form of elements, in particular with a rectangular cross-section, made from a laminated-bonded composite material, and the peripheral members ( 17   4 ) are beams, in particular with a rectangular cross-section made from a laminated-bonded composite material linked in pairs on either side of the radiating ribs ( 16   4 ) by a series of rings ( 27 ) rigidly secured to one another and also made from a laminated-bonded composite material.  
   
   
       11 . Diffuser as claimed in  claim 10 , characterised in that the internal face ( 18 ) and external face ( 19 ) of each of the radiating ribs ( 16   4 ) is linked by a series of rings ( 28 ) rigidly secured to one another and made from a laminated-bonded composite material.