Modular blade or vane for a gas turbine and gas turbine with such a blade or vane

Abstract

The invention relates to a modular blade or vane for a gas turbine, which includes the modular components of a platform element with a planar or contoured surface defining a platform level and a through-opening therein, and an airfoil, extending through the platform element. The airfoil includes a load carrying structure extending along a longitudinal axis of the airfoil, having a root portion for fastening on a blade or vane carrier of the gas turbine, having a tip portion, and having at least one interior passage, extending from the root portion to the tip portion of the airfoil. An aerodynamically shaped shell extends in a distance over the carrying structure and defining the outer contour of the airfoil. A longitudinally extending gap, is disposed between the carrying structure and the shell. A number of through-holes in the carrying structure direct a cooling medium from the interior passage into the gap. The shell is integrally joined to said carrying structure by a first joint in a region below the platform level of the platform element. The shell is joined to the carrying structure by at least one additional joint, wherein said at least one additional joint is a form-fit joint, allowing relative movement in longitudinal direction between shell and carrying structure.

What is claimed is: 
     
         1 . A modular blade or vane for a gas turbine the modular blade or vane comprising the modular components of:
 a platform element with a planar or contoured surface defining a platform level and a through-opening therein, and   an airfoil, extending through the platform element,   wherein the airfoil having:   a load carrying structure extending along a longitudinal axis of the airfoil, having a root portion for fastening on a blade or vane carrier of the gas turbine, having a tip portion, and having at least one interior passage, extending from the root portion to the tip portion of the airfoil,   an aerodynamically shaped shell extending in a distance over the carrying structure and defining the outer contour of the airfoil,   a longitudinally extending gap, defined between the carrying structure and the shell, a number of through-holes in the carrying structure for directing a cooling medium from the interior passage into the gap,   wherein   the shell being integrally joined to said carrying structure by a first joint in a region below the platform level of the platform element; and the shell being joined to the carrying structure by at least one additional joint, wherein said at least one additional joint is a form-fit joint, allowing relative movement in longitudinal direction between shell and carrying structure.   
     
     
         2 . The modular blade or vane according to  claim 1 , wherein the first joint between shell and carrying structure is a welded joint, a brazed joint or a retainer joint. 
     
     
         3 . The modular blade or vane according to  claim 1 , wherein the first joint between the shell and the carrying structure is gastight. 
     
     
         4 . The modular blade or vane according to  claim 1 , wherein said at least one additional joint comprises an edge of the shell fitting into a groove, formed in a component at the tip of the airfoil. 
     
     
         5 . The modular blade or vane according to  claim 4 , wherein said tip component is a shroud element or a tip cap. 
     
     
         6 . The modular blade or vane according to  claim 4 , wherein said additional joint allows leakage of the cooling medium. 
     
     
         7 . The modular blade or vane according to  claim 4 , wherein the groove is machined in the tip component of the airfoil. 
     
     
         8 . The modular blade or vane according to  claim 1 , wherein the outer surface of the carrying structure and the inner surface of the shell are equipped with a number of complementary form-fitting elements for lateral fixation of the shell to the carrying structure. 
     
     
         9 . The modular blade or vane according to  claim 8 , wherein the complementary form-fitting elements are designed as a dovetail. 
     
     
         10 . The modular blade or vane according to  claim 1 , wherein the cooling medium, directed into gap, impinges the inner surface of the shell. 
     
     
         11 . The modular blade or vane according to  claim 1 , wherein the outer surface of the carrying structure and/or the inner surface of the shell are equipped with turbulators for enhancing heat transfer. 
     
     
         12 . The modular blade or vane according to  claim 11 , wherein the turbulators are ribs or pedestals. 
     
     
         13 . The modular blade or vane according to  claim 11 , wherein individual turbulators are designed to provide support to the shell. 
     
     
         14 . A gas turbine with a modular blade or vane, wherein said modular blade or vane is a blade or vane according to  claim 1 .