Passive control of gas turbine clearances using ceramic matrix composites inserts

Abstract

A passive clearance control limits thermal expansion between stator components relative to rotor components. A control ring controls clearance in a passive manner and is located on or adjacent to stationary components which thermally expand during engine operation. The control ring is formed of material having low coefficient of thermal expansion such as CMCs (Ceramic Matrix Composites) and therefore limits, inhibits or restrains expansion of the adjacent stator components as temperatures increase. Limiting expansion of the stator component reduces rotor/stator clearances and limits parasitic leakage of fluid along the flow path through the engine core.

What is claimed is: 
     
         1 . A clearance control ring assembly, comprising:
 a stator component disposed opposite a rotor component within a gas turbine engine; and   a clearance control ring being formed of a single structure and extending circumferentially disposed radially outward of at least a portion of said stator component;   
       said clearance control ring having a coefficient of thermal expansion lower than a coefficient of thermal expansion of said at least a portion of said stator component; 
       wherein said at least a portion of said stator component is limited from thermal expansion and limited from growth relative to said rotor component. 
     
     
         2 . The clearance control ring assembly of  claim 1 , wherein said clearance control ring is positioned on a compressor discharge pressure seal. 
     
     
         3 . The clearance control ring assembly of  claim 2 , wherein the compressor discharge pressure seal comprises a stator component and a rotor component. 
     
     
         4 . The clearance control ring assembly of  claim 3 , wherein said stator component is disposed opposite the rotor component and comprises at least an abradable material and a support arm. 
     
     
         5 . The clearance control ring of  claim 4 , wherein a ceramic matrix composite control ring is disposed radially outward of the support arm. 
     
     
         6 . The clearance control ring assembly of  claim 4 , wherein said rotor component comprises a labyrinth seal rotating adjacent said abradable material. 
     
     
         7 . The clearance control ring assembly of  claim 6 , wherein said labyrinth seal comprises a plurality of seal teeth extending generally radially outward. 
     
     
         8 . The clearance control ring assembly of  claim 1 , wherein said clearance control ring is disposed in a compressor of the gas turbine engine. 
     
     
         9 . The clearance control ring assembly of  claim 1 , wherein said stator component includes a blade ring. 
     
     
         10 . The clearance control ring assembly of  claim 9 , wherein said clearance control ring is disposed outwardly and circumferentially about said blade ring. 
     
     
         11 . A gas turbine engine, comprising:
 a compressor;   a propulsor;   an engine inlet end;   a multi-stage high pressure turbine; and   a clearance control ring assembly, the clearance control ring assembly comprising:   a stator component disposed opposite a rotor component within the gas turbine engine; and   a clearance control ring being formed of a single structure and extending circumferentially disposed radially outward of at least a portion of said stator component;   
       said clearance control ring having a coefficient of thermal expansion lower than a coefficient of thermal expansion of said at least a portion of said stator component; 
       wherein said at least a portion of said stator component is limited from thermal expansion and limited from growth relative to said rotor component. 
     
     
         12 . The gas turbine engine of  claim 11 , wherein the clearance control ring is positioned on a compressor discharge pressure seal. 
     
     
         13 . The gas turbine engine of  claim 12 , wherein the compressor discharge pressure seal comprises a stator component and a rotor component. 
     
     
         14 . The gas turbine engine of  claim 13 , wherein said stator component is disposed opposite the rotor component and comprises at least an abradable material and a support arm. 
     
     
         15 . The gas turbine engine of  claim 14 , wherein said rotor component comprises a labyrinth seal rotating adjacent said abradable material. 
     
     
         16 . The gas turbine engine of  claim 15 , wherein said labyrinth seal comprises a plurality of seal teeth extending generally radially outward. 
     
     
         17 . The gas turbine engine of  claim 14 , wherein a ceramic matrix composite control ring is disposed radially outward of the support arm. 
     
     
         18 . The gas turbine engine of  claim 11 , wherein said clearance control ring is disposed in the compressor of the gas turbine engine. 
     
     
         19 . The gas turbine engine of  claim 11 , wherein said stator component includes a blade ring. 
     
     
         20 . The gas turbine engine of  claim 19 , wherein said clearance control ring is disposed outwardly and circumferentially about said blade ring.