Adjustable clearance control system for airfoil tip in gas turbine engine

Abstract

An airfoil system for use in a gas turbine engine having an adjustable clearance control system including an axially adjustable ring segment releasably coupled to the stationary turbine component whereby the axially adjustable ring segment may be controlled independently of other airfoil stages is disclosed The adjustable clearance control system may thus control the flow of hot gases passing one particular airfoil stage while the flow passing other airfoil stages within the component of the turbine engine remains unchanged The adjustable clearance control system may control the size of the gap between the axially adjustable ring segment and the tip of an airfoil through axial movement of the axially adjustable ring segment. The axially adjustable ring segment may include a radially inward contact surface that is positioned nonparallel and nonorthogonal relative to a direction of movement of the axial adjustable ring segment.

I claim: 
     
         1 . An airfoil system for use in a gas turbine engine, comprising:
 a rotor assembly having a plurality of airfoils extending radially therefrom and aligned axially to form a circumferentially extending row of airfoils forming an airfoil stage;   a stationary turbine component positioned radially outward from a tip of at least one airfoil;   an adjustable clearance control system including an axially adjustable ring segment releasably coupled to the stationary turbine component, wherein the axially adjustable ring segment is adjustable axially; and   wherein the axially adjustable ring segment is adjustable axially when positioned radially outward from a single row of turbine blades, thereby enabling the axially adjustable ring segment to be moved axially to change a gap size between the tip of the airfoil and the axially adjustable ring segment independently of other airfoil stages   
     
     
         2 . The airfoil system of  claim 1 , wherein the axially adjustable ring segment includes a radially inward segment contact surface having at least a portion aligned with the tip of the airfoil. 
     
     
         3 . The airfoil system of  claim 1 , wherein the axially adjustable ring segment includes a honeycomb seal land coupled to the axially adjustable ring segment 
     
     
         4 . The airfoil system of  claim 3 , wherein a radially inward contact surface of the honeycomb seal land is positioned nonparallel and nonorthogonal relative to a direction of movement of the axial adjustable ring segment. 
     
     
         5 . The airfoil system of  claim 1 , further comprising at least one rib extending radially outward from the tip of the turbine blade and terminating before contacting a radially inward contact surface of the axially adjustable ring segment 
     
     
         6 . The airfoil system of  claim 1 , wherein the plurality of airfoils forming the circumferentially extending row of airfoils forming the airfoil stage forms an airfoil stage closest to an exhaust diffuser. 
     
     
         7 . The airfoil system of  claim 1 , wherein the axially adjustable ring segment of the adjustable clearance control system extends at least partially circumferentially about the airfoil stage. 
     
     
         8 . An airfoil system for use in a gas turbine engine, comprising:
 a rotor assembly having a plurality of airfoils extending radially therefrom and aligned axially to form a circumferentially extending row of airfoils forming an airfoil stage;   a stationary turbine component positioned radially outward from a tip of at least one airfoil;   an adjustable clearance control system including an axially adjustable ring segment releasably coupled to the stationary turbine component, wherein the axially adjustable ring segment is adjustable axially;   wherein the axially adjustable ring segment is adjustable axially when positioned radially outward from a single row of turbine blades, thereby enabling the axially adjustable ring segment to be moved axially to change a gap size between the tip of the airfoil and the axially adjustable ring segment independently of other airfoil stages; and   a radially inward segment contact surface of the axially adjustable ring segment is positioned nonparallel and nonorthogonal relative to a direction of movement of the axial adjustable ring segment   
     
     
         9 . The airfoil system of  claim 8 , wherein the axially adjustable ring segment includes a radially inward contact surface having at least a portion aligned with the tip of the airfoil 
     
     
         10 . The airfoil system of  claim 8 , wherein the axially adjustable ring segment includes a honeycomb seal land coupled to the axially adjustable ring segment 
     
     
         11 . The airfoil system of  claim 8 , further comprising at least one rib extending radially outward from the tip of the turbine blade and terminating before contacting a radially inward contact surface of the axially adjustable ring segment. 
     
     
         12 . The airfoil system of  claim 8 , wherein the plurality of airfoils forming the circumferentially extending row of airfoils forming the airfoil stage forms an airfoil stage closest to an exhaust diffuser. 
     
     
         13 . The airfoil system of  claim 8 , wherein the axially adjustable ring segment of the adjustable clearance control system extends at least partially circumferentially about the airfoil stage 
     
     
         14 . An airfoil system for use in a gas turbine engine, comprising:
 a rotor assembly having a plurality of airfoils extending radially therefrom and aligned axially to form a circumferentially extending row of airfoils forming an airfoil stage;   a stationary turbine component positioned radially outward from a tip of at least one airfoil;   an adjustable clearance control system including an axially adjustable ring segment releasably coupled to the stationary turbine component, wherein the axially adjustable ring segment is adjustable axially;   wherein the axially adjustable ring segment is adjustable axially when positioned radially outward from a single row of turbine blades, thereby enabling the axially adjustable ring segment to be moved axially to change a gap size between the tip of the airfoil and the axially adjustable ring segment independently of other airfoil stages and without changing a tip clearance of other upstream airfoil stages;   wherein a radially inward segment contact surface of the axially adjustable ring segment is positioned nonparallel and nonorthogonal relative to a direction of movement of the axial adjustable ring segment; and   wherein the axially adjustable ring segment includes a honeycomb seal land coupled to the axially adjustable ring segment.   
     
     
         15 . The airfoil system of  claim 14 , wherein the axially adjustable ring segment includes a radially inward contact surface having at least a portion aligned with the tip of the airfoil. 
     
     
         16 . The airfoil system of  claim 14 , further comprising at least one rib extending radially outward from the tip of the turbine blade and terminating before contacting a radially inward contact surface of the axially adjustable ring segment 
     
     
         17 . The airfoil system of  claim 14 , wherein the plurality of airfoils forming the circumferentially extending row of airfoils forming the airfoil stage forms an airfoil stage closest to an exhaust diffuser. 
     
     
         18 . The airfoil system of  claim 14 , wherein the axially adjustable ring segment of the adjustable clearance control system extends at least partially circumferentially about the airfoil stage.