Turbomachine with unducted propellers

Abstract

Turbomachine, comprising two external coaxial and contra-rotating unducted propellers ( 122, 124 ), at least some of the blades ( 148 ) of the upstream propeller comprising substantially radial internal shafts for air circulation ( 150 ) communicating with air tapping orifices ( 152 ) in the boundary limits of the blades, and at their radially external ends with air outlet orifices ( 158 ).

1 . Turbomachine, comprising two coaxial and contra-rotating unducted external propellers, respectively upstream and downstream, wherein at least some of the blades of the upstream propeller include substantially radial internal air circulation shafts communicating with air tapping orifices in the boundary limits of the blades, and at their radially external ends with air outlet orifices, in such a way that the boundary limits are re-adhered to the blades and that the air circulates in the internal shafts of the blades and is evacuated towards the exterior by the outlet orifices in order to destroy the coherency of the vortices generated by the tops of the blades of the upstream propeller and as such reduce the clipping provoked by the interaction of these vortices with the blades of the downstream propeller, and in that the air tapping orifices are located on radially external end portions of the blades and exiting onto the upper surfaces of the blades. 
   
   
       2 . Turbomachine set forth in  claim 1 , wherein the air tapping orifices are distributed over a zone between 60 and 90% of the radial dimension of the blades, measured from the feet of these blades. 
   
   
       3 . Turbomachine set forth in  claim 1 , wherein the air tapping orifices have a general elongated or oblong form. 
   
   
       4 . Turbomachine set forth in  claim 3 , wherein the axes of elongation of the air tapping orifices are directed radially from upstream to downstream towards the exterior. 
   
   
       5 . Turbomachine according to  claim 1 , wherein the air outlet orifices are directed substantially radially or on a slant and are formed on the heads of the blades. 
   
   
       6 . Turbomachine according to  claim 1 , wherein the air outlet orifices are distributed over a zone between 5 and 95% of the chord or of the axial dimension of the blades, measured from the leading edges of these blades. 
   
   
       7 . Turbomachine according to  claim 1 , wherein the shafts are formed in a zone between 60 and 90% of the chord or of the axial dimension of the blades, measured from the leading edges of these blades. 
   
   
       8 . Turbomachine according to  claim 1 , wherein the upstream and downstream propellers substantially have the same external diameter. 
   
   
       9 . Unducted external propeller blade for a turbomachine according to  claim 1 , wherein its upper surface comprises orifices formed in a zone between 60 and 90% of the radial dimension of the blade, in relation to the axis of rotation of the propeller, measured from the foot of the blade, these orifices being connected by internal shafts of the blade to orifices formed on the head of the blade.