Methods and apparatus for cooling rotary components within a steam turbine

Abstract

A stationary component includes an outer ring including a first plenum, a first passageway, and a second plenum defined therein. The first passageway extends between the first plenum and the second plenum. An airfoil is disposed radially inward of the outer ring. The airfoil includes a second passageway defined therein. The second passageway is coupled in flow communication with the second plenum.

What is claimed is: 
     
         1 . A method for cooling a rotating component within a turbine, said method comprising:
 channeling a cooling fluid through an outer ring including a first plenum, a first passageway, and a second plenum defined therein, wherein the first passageway extends between the first plenum and the second plenum;   channeling the cooling fluid through an airfoil disposed radially inward of the outer ring, the airfoil including a second passageway defined therein, the second passageway coupled in flow communication with the second plenum; and   discharging the cooling fluid from the airfoil to facilitate cooling an adjacent rotating component.   
     
     
         2 . A method in accordance with  claim 1  wherein channeling a cooling fluid through the outer ring further comprises channeling the cooling fluid substantially radially through the outer ring between the first plenum and the second plenum. 
     
     
         3 . A method in accordance with  claim 1  wherein channeling a cooling fluid through the outer ring further comprises channeling the cooling fluid through a plurality of first passageways extending substantially radially between the first plenum and the second plenum, the first passageway included in the plurality for first passageways. 
     
     
         4 . A method in accordance with  claim 1  wherein channeling the cooling fluid through the airfoil further comprises channeling the cooling fluid substantially radially through the airfoil. 
     
     
         5 . A method in accordance with  claim 1  wherein channeling the cooling fluid through the airfoil further comprises channeling the cooling fluid through a plurality of second passageways extending substantially radially and coupled in flow communication with the second plenum, the second passageway included in the plurality of second passageways. 
     
     
         6 . A method in accordance with  claim 1  wherein discharging the cooling fluid further comprises discharging the cooling fluid through an outlet of the second passageway and into a wheelspace. 
     
     
         7 . A method in accordance with  claim 1  further comprising sealing the first plenum from a main steam path. 
     
     
         8 . A stationary component for use with a turbine, said stationary component comprising:
 an outer ring comprising a first plenum, a first passageway, and a second plenum defined therein, said first passageway extending between said first plenum and said second plenum; and   an airfoil disposed radially inward of said outer ring, said airfoil comprising a second passageway defined therein, said second passageway coupled in flow communication with said second plenum.   
     
     
         9 . A stationary component in accordance with  claim 8  wherein said first plenum is defined in a radially outer surface of said outer ring, and said second plenum is defined in a radially inner surface of said outer ring. 
     
     
         10 . A stationary component in accordance with  claim 8  wherein said first passageway extends substantially radially through said outer ring. 
     
     
         11 . A stationary component in accordance with  claim 8  wherein said outer ring comprises a plurality of first passageways extending substantially radially between said first plenum and said second plenum, said first passageway included in said plurality for first passageways. 
     
     
         12 . A stationary component in accordance with  claim 8  wherein said second passageway extends substantially radially through said airfoil. 
     
     
         13 . A stationary component in accordance with  claim 8  wherein said airfoil comprises a plurality of second passageways extending substantially radially and coupled in flow communication with said second plenum, said second passageway included in said plurality of second passageways. 
     
     
         14 . A stationary component in accordance with  claim 8  wherein said second passageway has an outlet oriented to discharge a cooling fluid into a wheelspace. 
     
     
         15 . A steam turbine comprising:
 a rotor shaft comprising a plurality of buckets coupled thereto;   a steam turbine casing; and   a stationary component coupled to said steam turbine casing, said stationary component disposed upstream from said plurality of buckets such that a wheelspace is defined between said plurality of buckets and said stationary component, said stationary component comprising an outer ring and an airfoil disposed radially inward of said outer ring, such that a cooling fluid flowpath is defined through at least said outer ring and said airfoil, said cooling fluid flowpath configured to channel a cooling fluid towards said wheelspace.   
     
     
         16 . A steam turbine in accordance with  claim 15  wherein said outer ring comprises a first plenum, a first passageway, and a second plenum defined therein, said first passageway extending between said first plenum and said second plenum, said first plenum, said first passageway, and said second plenum included in said cooling fluid flowpath. 
     
     
         17 . A steam turbine in accordance with  claim 16  wherein said outer ring comprises a seal coupled between said first plenum and a main steam flowpath, wherein said main steam flowpath is defined through said plurality of buckets and said stationary component. 
     
     
         18 . A steam turbine in accordance with  claim 16  wherein said first plenum is defined in a radially outer surface of said outer ring, and said second plenum is defined in a radially inner surface of said outer ring. 
     
     
         19 . A steam turbine in accordance with  claim 15  wherein said airfoil comprises a second passageway defined therein, said second passageway coupled in flow communication with said second plenum, said second passageway included in said cooling fluid flowpath. 
     
     
         20 . A steam turbine in accordance with  claim 19  wherein said second passageway has an outlet oriented to discharge the cooling fluid into said wheelspace.