Turbomachine having clearance control capability and system therefor

Abstract

A turbomachine having clearance control capability is provided and includes a turbine stage including a blade configured to rotate around a centerline, a movable portion of a casing circumferentially surrounding the turbine stage and a rotatable cam operably coupled to the movable portion and thereby configured to control an axial position of the movable portion. A radially outermost tip of the blade and an interior surface of the movable portion are sloped with respect to the centerline such that the controlled axial position of the movable portion is determinative of a clearance between the blade and the movable portion.

1 . A turbomachine having clearance control capability, comprising:
 a turbine stage including a blade configured to rotate around a centerline;   a movable portion of a casing circumferentially surrounding the turbine stage; and   a rotatable cam operably coupled to the movable portion and thereby configured to control an axial position of the movable portion,   a radially outermost tip of the blade and an interior surface of the movable portion being sloped with respect to the centerline such that the controlled axial position of the movable portion is determinative of a clearance between the blade and the movable portion.   
     
     
         2 . The turbomachine according to  claim 1 , wherein the blade is plural and the plurality of the blades are circumferentially arrayed around the centerline. 
     
     
         3 . The turbomachine according to  claim 1 , wherein the tip and the interior surface are disposable substantially in parallel with one another. 
     
     
         4 . The turbomachine according to  claim 1 , wherein the rotatable cam comprises:
 a drive shaft; and   a head portion, which is coupled off-center to the drive shaft.   
     
     
         5 . The turbomachine according to  claim 1 , wherein the movable portion comprises a radially exterior surface defining a cam seat, which is receptive of the rotatable cam. 
     
     
         6 . The turbomachine according to  claim 5 , wherein the cam seat is configured to interfere with the rotatable cam such that, as the rotatable cam rotates in first or second opposite directions, the movable portion moves in first or second opposite axial directions, respectively. 
     
     
         7 . The turbomachine according to  claim 5 , wherein the cam seat comprises a pair of substantially parallel circumferential wall surfaces. 
     
     
         8 . The turbomachine according to  claim 1 , wherein the movable portion comprises:
 a central body; and   flanges extending in forward and aft directions from the central body, respectively,   the flanges being movable in forward and aft axial directions within first and second recesses defined in forward and aft portions, respectively, the forward and aft portions being disposed forward and aft of the movable portion, respectively.   
     
     
         9 . The turbomachine according to  claim 1 , further comprising an anti-rotation feature disposed on the movable portion. 
     
     
         10 . The turbomachine according to  claim 1 , wherein the turbine stage comprises at least one or more turbine stages, each of which is circumferentially surrounded by the movable portion. 
     
     
         11 . A turbomachine having clearance control capability, comprising:
 a turbine stage including a blade configured to rotate around a centerline;   a casing circumferentially surrounding the turbine stage and including forward, aft and movable portions, the movable portion being axially interposed and secured between the forward and aft portions and defining a cam seat in a radially exterior surface thereof; and   a rotatable cam received within and operably coupled to the cam seat of the movable portion, the rotatable cam being thereby configured to control an axial position of the movable portion in accordance with rotation thereof,   a radially outermost tip of the blade and an interior surface of the movable portion being sloped with respect to the centerline such that the controlled axial position of the movable portion is determinative of a clearance between the blade and the movable portion.   
     
     
         12 . The turbomachine according to  claim 11 , wherein the blade is plural and the plurality of the blades are circumferentially arrayed around the centerline. 
     
     
         13 . The turbomachine according to  claim 11 , wherein the tip and the interior surface are disposable substantially in parallel with one another. 
     
     
         14 . The turbomachine according to  claim 11 , wherein the rotatable cam comprises:
 a drive shaft; and   a head portion, which is coupled off-center to the drive shaft.   
     
     
         15 . The turbomachine according to  claim 14 , wherein the cam seat is configured to interfere with the head portion of the rotatable cam such that, as the rotatable cam rotates in first or second opposite directions about the drive shaft, the movable portion moves in first or second opposite axial directions, respectively. 
     
     
         16 . The turbomachine according to  claim 14 , wherein the cam seat comprises a pair of substantially parallel circumferential wall surfaces. 
     
     
         17 . The turbomachine according to  claim 11 , wherein the movable portion comprises:
 a central body; and   flanges extending in forward and aft directions from the central body, respectively,   the flanges being movable in forward and aft axial directions within first and second recesses defined in the forward and aft portions, respectively.   
     
     
         18 . The turbomachine according to  claim 11 , further comprising anti-rotation features disposed on the movable portion. 
     
     
         19 . The turbomachine according to  claim 11 , wherein the turbine stage comprises at least one or more turbine stages, each of which is circumferentially surrounded by the movable portion. 
     
     
         20 . A system providing a turbomachine with clearance control capability, comprising:
 at least one or more turbine stages, each of the at least one or more turbine stages including a blade configured to rotate around a centerline;   a movable portion of a casing circumferentially surrounding the at least one or more turbine stages;   a rotatable cam operably coupled to the movable portion and thereby configured to control an axial position of the movable portion; and   a controller,   a radially outermost tip of the blade of each of the at least one or more turbine stages and an interior surface of the movable portion being sloped with respect to the centerline such that the controlled axial position of the movable portion is determinative of a clearance between the blade of each of the at least one or more turbine stages and the movable portion, and   the controller being operably coupled to the rotatable cam and thereby configured to control operations of the rotatable cam.