Turbine blade for a water turbine with bi-directional flow

Abstract

The invention relates to a turbine blade for a water turbine, comprising, at least over part of its length, a curved profiled element having a median line created point-symmetrically in relation to a point of symmetry on the chord of the profiled element, half-way down, in such a way as to form an S-shaped curve. The median line splits the profiled element into a first side and a second side. The invention is characterised in that the turbine blade comprises an overflow device between the first side and the second side of the profiled element.

1 . A turbine blade for a water turbine, having a cambered profile with a median line ( 32 ) in at least a portion of its length, that is designed to be symmetrical about a point in relation to a point of symmetry ( 27 ) lying at the midpoint of the profile length on the profile chord ( 20 ), and forming an S-curve, wherein the median line ( 32 ) divides the profile into a first profile surface ( 21 ) and a second profile surface ( 22 ), and wherein the profile comprises a midline ( 23 ) that depicts aright angle to the profile chord ( 20 ) having the symmetry point ( 27 ) as its starting point, and which divides the profile into a first profile half ( 24 ) and a second profile half ( 25 ), characterized in that the turbine blade comprises an overflow device ( 1 ), which establishes a fluid connection between the first profile surface ( 21 ) and the second profile surface ( 22 ), wherein the overflow device ( 1 ) comprises a first off-center overflow channel ( 5 ,  5 . 1 , . . . ,  5 . n ), which establishes a fluid connection between the first profile surface ( 21 ) and the second profile surface ( 22 ) in the first profile half ( 24 ), and a second off-center overflow channel ( 6 ,  6 . 1 , . . . ,  6 . n ), which establishes a fluid connection between the first profile surface ( 21 ) and the second profile surface ( 22 ) in the second profile half ( 25 ), and the first off-center overflow channel ( 5 ,  5 . 1 , . . . ,  5 . n ) has a dedicated first channel closing component ( 7 . 1 ,  7 . 2 ) and the second off-center overflow channel ( 6 ,  6 . 1 , . . . ,  6 . n ) has a dedicated second channel closing component ( 10 . 1 ,  10 . 2 ), which are configured for the selective closing of the respective off-center overflow channels, depending on the direction of flow. 
     
     
         2 . The turbine blade according to  claim 1 , characterized in that the selective closing of the first off-center overflow channel ( 5 ,  5 . 1 , . . . ,  5 . n ) and the second overflow channel ( 6 ,  6 . 1 , . . . ,  6 . n ) are caused by passive means. 
     
     
         3 . The turbine blade according to  claim 2 , characterized in that a first elastic profile component ( 8 ,  8 . 1 , . . . ,  8 . n ) on the second profile surface ( 22 ) is used for the passive control of the first channel closing component ( 7 ,  7 . 1 ,  7 . 2 ), and a second elastic profile component ( 11 ) on the first profile surface ( 21 ) is used for the passive control of the second channel closing component ( 10 . 1 ,  10 . 2 ). 
     
     
         4 . The turbine blade according to  claim 1 , characterized in that the overflow device ( 1 ) comprises a first adaptive wall component ( 3 ) and a second adaptive wall component ( 4 ), which are disposed symmetrically about a point of symmetry ( 27 ). 
     
     
         5 . The turbine blade according to  claim 4 , characterized in that the first adaptive wall component ( 3 ) and the second adaptive wall component ( 4 ) function as passive components, the contours of which are affected by the flow forces. 
     
     
         6 . The turbine blade according to  claim 4 , characterized in that the first adaptive wall component ( 3 ) comprises a first active, adaptive wall component ( 16 ), and the second wall component ( 4 ) comprises a second active, adaptive wall component ( 17 ). 
     
     
         7 . A method for operating a turbine blade for a water turbine with bi-directional flow, having a cambered profile with a median line ( 32 ) in at least a portion of its length, that is designed to be symmetrical about a point in relation to a point of symmetry ( 27 ) lying at the midpoint of the profile length on the profile chord ( 20 ), and forming an S-curve, wherein the median line ( 32 ) divides the profile into a first profile surface ( 21 ) and a second profile surface ( 22 ), and the turbine blade comprises a first off-center overflow channel ( 5 ,  5 . 1 , . . . ,  5 . n ), which establishes a fluid connection between the first profile surface ( 21 ) and the second profile surface ( 22 ) in the first profile half ( 24 ), and a second off-center overflow channel ( 6 ,  6 . 1 , . . . ,  6 . n ), which establishes a fluid connection between the first profile surface ( 21 ) and the second profile surface ( 22 ) in the second profile half ( 25 ), and wherein the first off-center overflow channel ( 5 ,  5 . 1 , . . . ,  5 . n ) comprises first channel closing component ( 7 . 1 ,  7 . 2 ) and the second off-center overflow channel ( 6 ,  6 . 1 , . . . ,  6 . n ) comprises second channel closing component ( 10 . 1 ,  10 . 2 ), and wherein, by means of the respectively dedicated channel closing component, depending on the direction of flow, the upstream off-center overflow channel is closed, and the downstream off-center overflow channel is opened. 
     
     
         8 . The turbine blade according to  claim 2 , characterized in that the overflow device comprises a first adaptive wall component and a second adaptive wall component, which are disposed symmetrically about a point of symmetry. 
     
     
         9 . The turbine blade according to  claim 3 , characterized in that the overflow device comprises a first adaptive wall component and a second adaptive wall component, which are disposed symmetrically about a point of symmetry.