Blade arrangement of a gas turbine

Abstract

A blade arrangement of a gas turbine, with at least one blade which in the radial direction projects into a hot gas passage arranged concentrically to an axis, and terminates in a blade tip which with a clearance lies opposite a heat shield which delimits the hot gas passage. The blade and the heat shield are movable in relation to each other in the circumferential direction, and the blade tip and the heat shield are covered with coatings, which enable a directed cutting of the blade tip into the heat shield. By such a blade arrangement, a reduction of the clearance as a result of cutting in is simply achieved by the heat shield having a porous thermal barrier coating as an outer, abradable coating, and by the blade tip being provided with a homogenous, metallic cover coating.

1 . A blade arrangement ( 30 ) of a thermal turbomachine with at least one blade ( 11 ), which projects in the radial direction into a passage ( 13 ) which is arranged concentrically to an axis ( 16 ) and is exposed to throughflow by hot gas, the at least one blade terminates in a blade tip ( 27 ) which with a clearance ( 25 ) lies opposite a heat shield ( 12 ) which delimits the passage ( 13 ), wherein the at least one blade ( 11 ) and the heat shield ( 12 ) are movable in relation to each other in a circumferential direction, and the blade tip ( 27 ) and the heat shield ( 12 ) are covered with coatings ( 22 ,  23 ,  24 ) which enable a directed cutting of the blade tip ( 27 ) into the heat shield ( 12 ), the heat shield ( 12 ) has a porous thermal barrier coating ( 23 ) as an outer, abradable coating, and the blade tip ( 27 ) is provided with a homogenous, metallic cover coating ( 24 ). 
     
     
         2 . The blade arrangement as claimed in  claim 1 , wherein the thermal turbomachine is a gas turbine, the at least one blade is a rotor blade ( 11 ) which rotates around the axis ( 16 ), and the heat shield ( 12 ) is installed on a stator of the gas turbine in a fixed manner. 
     
     
         3 . The blade arrangement as claimed in  claim 1 , wherein the thermal barrier coating ( 23 ) is a porous ceramic coating, comprising YSZ. 
     
     
         4 . The blade arrangement as claimed in  claim 3 , wherein a porosity of the thermal barrier coating ( 23 ) is more than 20%. 
     
     
         5 . The blade arrangement as claimed in  claim 3 , wherein an adhesion coating ( 22 ), comprising MCrAlY, is arranged between the heat shield ( 12 ) and the thermal barrier coating ( 23 ). 
     
     
         6 . The blade arrangement as claimed in  claim 1 , wherein the metallic cover coating ( 24 ) comprises MCrAlY. 
     
     
         7 . The blade arrangement as claimed in  claim 2 , wherein the rotor blade ( 11 ) is part of a first rotor-blade row in a turbine section of the gas turbine. 
     
     
         8 . The blade arrangement as claimed in  claim 2 , wherein the thermal barrier coating ( 23 ) is a porous ceramic coating, comprising YSZ. 
     
     
         9 . The blade arrangement as claimed in  claim 8 , wherein a porosity of the thermal barrier coating ( 23 ) is more than 20%. 
     
     
         10 . The blade arrangement as claimed in  claim 8 , wherein an adhesion coating ( 22 ), comprising MCrAlY, is arranged between the heat shield ( 12 ) and the thermal barrier coating ( 23 ). 
     
     
         11 . The blade arrangement as claimed in  claim 2 , wherein the metallic cover coating ( 24 ) comprises MCrAlY.