Blade for a gas turbine

Abstract

A blade is provided for a gas turbine, especially for the low-pressure turbine of a gas turbine with sequential combustion, and is produced in accordance with a casting process and has a blade airfoil which extends in the radial direction between an inner platform and an outer platform, and in the interior of which extends a cooling passage, bypassing the platforms, and through which flows a cooling medium, especially cooling air, for cooling the blade. In the outer and/or inner platform there are core outlet openings which arise from the use of a casting core and which connect the cooling passage to the outside space and are sealed off by means of a sealing element. Optimum cooling is ensured by the sealing elements being formed and inserted into the core outlet openings so that they align with the wall surface of the cooling passage in a flush manner.

What is claimed is: 
     
         1 . A blade ( 20 ) for a gas turbine ( 10 ), said blade ( 20 ) being produced in accordance with a casting process and comprises a blade airfoil ( 22 ) which extends in a radial direction between a blade tip ( 23 ) and a shroud ( 21 ) and in an interior of which extends a cooling passage ( 39 ), which bypasses the shroud and blade tip ( 21 ,  23 ), and through which flows a cooling medium for cooling the blade ( 20 ), wherein in end-face ends ( 21  or  23 ) of the blade ( 20 ) there are core outlet openings ( 40  or  41 ) which arise from the use of a casting core and which connect the cooling passage ( 39 ) to an outside space and are sealed off by a sealing element ( 32  or  36 ), the sealing element ( 32 ,  36 ) is formed and inserted into the core outlet openings ( 40 ,  41 ) so that it aligns with a wall surface of the cooling passage ( 39 ) in a flush manner. 
     
     
         2 . The blade as claimed in  claim 1 , wherein the sealing elements are formed as prefabricated sealing plugs ( 32 ,  36 ). 
     
     
         3 . The blade as claimed in  claim 1 , wherein the sealing elements ( 32 ,  36 ) are hard-soldered into the core outlet openings ( 40 ,  41 ). 
     
     
         4 . The blade as claimed in  claim 3 , wherein abutment surfaces ( 33 ,  37 ), upon which lie the sealing elements ( 32 ,  36 ), are formed in the core outlet openings ( 40 ,  41 ). 
     
     
         5 . The blade as claimed in  claim 1 , wherein the sealing elements ( 32 ,  36 ) are inserted into the core outlet openings ( 40 ,  41 ) so that they align with outer surfaces of the shroud and blade tip ( 21 ,  23 ) in a flush manner. 
     
     
         6 . The blade as claimed in  claim 2 , wherein the sealing plugs ( 32 ,  36 ) are hard-soldered into the core outlet openings ( 40 ,  41 ). 
     
     
         7 . The blade as claimed in  claim 6 , wherein abutment surfaces ( 33 ,  37 ), upon which lie the sealing plugs ( 32 ,  36 ), are formed in the core outlet openings ( 40 ,  41 ). 
     
     
         8 . The blade as claimed in  claim 2 , wherein the sealing plugs ( 32 ,  36 ) are inserted into the core outlet openings ( 40 ,  41 ) so that they align with outer surfaces of the shroud and blade tip ( 21 ,  23 ) in a flush manner. 
     
     
         9 . A gas turbine comprising a blade ( 20 ), said blade ( 20 ) being produced in accordance with a casting process and has a blade airfoil ( 22 ) which extends in a radial direction between a blade tip ( 23 ) and a shroud ( 21 ) and in an interior of which extends a cooling passage ( 39 ), which bypasses the shroud and blade tip ( 21 ,  23 ), and through which flows a cooling medium for cooling the blade ( 20 ), wherein in end-face ends ( 21  or  23 ) of the blade ( 20 ) there are core outlet openings ( 40  or  41 ) which arise from the use of a casting core and which connect the cooling passage ( 39 ) to an outside space and are sealed off by a sealing element ( 32  or  36 ), the sealing element ( 32 ,  36 ) is formed and inserted into the core outlet openings ( 40 ,  41 ) so that they align with a wall surface of the cooling passage ( 39 ) in a flush manner, wherein the blade ( 20 ) is arranged in a turbine ( 15 ,  18 ) of the gas turbine ( 10 ). 
     
     
         10 . The gas turbine as claimed in  claim 9 , wherein the gas turbine ( 10 ) is a gas turbine with sequential combustion, having a first combustion chamber ( 14 ) with a downstream high-pressure turbine ( 15 ), and a second combustion chamber ( 17 ) with a downstream low-pressure turbine ( 18 ), and the blade ( 20 ) is a stator blade which is arranged in the low-pressure turbine ( 18 ). 
     
     
         11 . The gas turbine as claimed in  claim 10 , wherein the low-pressure turbine has a plurality of rows of stator blades arranged in series in the flow direction, and the stator blade ( 20 ) is arranged in a middle stator blade row. 
     
     
         12 . The gas turbine as claimed in  claim 9 , wherein the blade ( 20 ) is a rotor blade.