Cooled airfoil, guide vane, and method for manufacturing the airfoil and guide vane

Abstract

Disclosed is a cooled airfoil having a hub end and tip, an airfoil height being defined between the hub end and the tip. The airfoil has a leading edge, trailing edge, suction side and pressure side. The airfoil has a first airfoil height section adjacent the hub end and extending towards the tip, wherein, in a meridional view, the leading edge and trailing edge are straight along the first airfoil height section. The airfoil has a second airfoil height section adjacent the tip and extending towards the hub end, wherein, in a meridional view, the airfoil is concavely shaped at the leading edge and is convexly shaped at the trailing edge along the second airfoil height section. At least one cooling channel has a length principally extending along the airfoil height, extends straight in a first cooling channel length section, and is bent in a second cooling channel length section.

1 . A cooled airfoil, the airfoil comprising:
 a hub end and a tip, an airfoil height being defined between the hub end and a tip,   a leading edge, a trailing edge, a suction side and a pressure side,   a first airfoil height section adjacent the hub end and extending towards the tip, wherein, in a meridional view, the leading edge and the trailing edge are straight along the first airfoil height section   a second airfoil height section adjacent the tip and extending towards the hub end, wherein, in a meridional view, the airfoil is concavely shaped at the leading edge and is convexly shaped at the trailing edge along the second airfoil height section,   wherein at least one cooling channel is provided within the airfoil and has a length principally extending along the airfoil height,   wherein the cooling channel extends straight in a first cooling channel length section and is bent in a second cooling channel length section, and   wherein a cooling channel wall provided on the leading edge side is convexly shaped and a cooling channel wall provided on the trailing edge side is concavely shaped.   
     
     
         2 . The airfoil according to  claim 1 ,
 wherein the first cooling channel length section is provided in the first airfoil height section and the second cooling channel length section is provided in the second airfoil height section.   
     
     
         3 . The airfoil according to  claim 1 ,
 wherein, in an axial view, the airfoil at the leading edge is straight at least in the first airfoil height section.   
     
     
         4 . The airfoil according to  claim 3 ,
 wherein, in the axial view, the airfoil is curved at the leading edge in the second airfoil height section, and is in particular concavely bent at the leading edge on the suction side in the second airfoil height section.   
     
     
         5 . The airfoil according to  claim 1 ,
 wherein, in an axial view, the airfoil at the trailing edge is straight at least in the first airfoil height section.   
     
     
         6 . The airfoil according to  claim 5 ,
 wherein, in the axial view, the airfoil at the trailing edge is curved in the second airfoil height section and is in particular concavely bent on the pressure side at the trailing edge in the second airfoil height section.   
     
     
         7 . The airfoil according to  claim 1 ,
 wherein it comprises an internal leading edge cooling channel adjacent the leading edge,   wherein the leading edge cooling channel at least generally follows the shape of the leading edge.   
     
     
         8 . The airfoil according to  claim 1 ,
 wherein the airfoil having an internal trailing edge cooling channel adjacent the trailing edge,   wherein the trailing edge cooling channel at least generally follows the shape of the trailing edge.   
     
     
         9 . The airfoil according to  claim 1 ,
 wherein the first airfoil height section covers 40% or more of the airfoil total height, starting at the hub end of the airfoil.   
     
     
         10 . A cooled turbine guide vane, comprising:
 an airfoil according to  claim 1 ,   a vane tip platform provided at the airfoil tip and the airfoil extending from a hot gas side of the tip platform,   the vane tip platform being provided with attachment means for fixing the vane to a turbine stator, the attachment means being provided opposite the hot gas side.   
     
     
         11 . The vane according to  claim 10 ,
 wherein at least one of the leading edge and the trailing edge at the airfoil tip ( 9 ) forms an angle (c, d) with the hot gas side of the tip platform when seen in a meridional view of the vane, wherein the angle is 90°±15°.   
     
     
         12 . The vane according to  claim 10 ,
 wherein the vane comprises a hub platform at the airfoil hub end, the hub platform having a hub platform hot gas side from which the airfoil extends,   wherein at least one of the leading edge and the trailing edge at the airfoil tip forms an angle with the hot gas side of the hub platform when seen in a meridional view of the vane,   wherein the angle is 90°±15°.   
     
     
         13 . A method for manufacturing an airfoil according to  claim 1 , the method comprising:
 providing a mold, the mold being provided to generate the outer surface shape at least of the airfoil in a casting process;   providing at least one core, the core being provided to generate at least one internal cooling channel in the airfoil in the casting process,   each of the mold and the core comprising a hub end and a tip end, and an airfoil length extending between the hub end and the tip end,   each of a cavity of the mold, and the core, comprising a straight section provided adjacent the respective hub end and a bent section provided adjacent the respective tip end,   placing the core inside the mold cavity,   placing the core bent section inside the mold cavity bent section,   placing the core straight section inside the mold cavity straight section;   wherein the core is attached to the mold in a fixed bearing relationship at the core tip end, and   wherein the core is attached to the mold in a floating bearing relationship at the core hub end such that the core hub end is enabled to displace relative to the mold along a lengthwise direction of the core straight section and is fixed relative to the mold in any direction across the lengthwise direction of the core straight section.   
     
     
         14 . The method according to  claim 13 , comprising:
 manufacturing a vane with the airfoil.   
     
     
         15 . A gas turbine engine, comprising:
 a cooled guide vane according to  claim 10 ,   wherein the guide vane is a guide vane of at least one of a third and fourth turbine stage.