Low pressure steam turbine including pivotable nozzle

Abstract

A low pressure steam turbine is disclosed including a rotor having: a rotor body; and a plurality of bucket stages disposed axially along the rotor body, the plurality of bucket stages including a last bucket stage; and a nozzle assembly at least partially surrounding the rotor, the nozzle assembly including a plurality of nozzle stages corresponding to the plurality of bucket stages, wherein a nozzle in a nozzle stage axially upstream of the last bucket stage is adjustable to modify a fluid flow within the last bucket stage during operation of the low pressure steam turbine.

1 . A low pressure steam turbine section comprising:
 a rotor having:
 a rotor body; and 
 a plurality of bucket stages disposed axially along the rotor body, the plurality of bucket stages including a last bucket stage; and 
   a nozzle assembly at least partially surrounding the rotor, the nozzle assembly including a plurality of nozzle stages corresponding to the plurality of bucket stages,   wherein a nozzle in a nozzle stage axially upstream of the last bucket stage is adjustable to modify a fluid flow within the last bucket stage during operation of the steam turbine.   
     
     
         2 . The steam turbine of  claim 1 , wherein the nozzle is one of a plurality of nozzles in the nozzle stage axially upstream of the last bucket stage, and wherein each of the plurality of nozzles is pivotable about a respective axis. 
     
     
         3 . The steam turbine of  claim 1 , wherein the nozzle is pivotable about an axis substantially perpendicular with a primary axis of the rotor body. 
     
     
         4 . The steam turbine of  claim 1 , wherein the nozzle is pivotable about an axis substantially parallel with a primary axis of the rotor body. 
     
     
         5 . The steam turbine of  claim 1 , wherein the nozzle is pivotable at an angle of approximately 30 degrees. 
     
     
         6 . The steam turbine of  claim 1 , wherein the nozzle includes a blade having:
 a first segment; and   a second segment operably connected to the first segment along the axis,   wherein the first segment is configured to pivot relative to the second segment about the axis.   
     
     
         7 . A low pressure steam turbine system comprising:
 a diffuser section;   a turbine coupled to the diffuser section, the turbine including:
 a rotor having:
 a rotor body; and 
 a plurality of bucket stages disposed axially along the rotor body, the plurality of bucket stages including a last bucket stage; 
 
 a nozzle assembly at least partially surrounding the rotor, the nozzle assembly including a plurality of nozzle stages corresponding to the plurality of bucket stages, 
 wherein a nozzle in a nozzle stage axially upstream of the last bucket stage is adjustable to modify a fluid flow within the last bucket stage or the diffuser during operation of the steam turbine; and 
   a control system operably connected to the nozzle stage, the control system configured to actuate pivoting of the nozzle in response to a predetermined load condition.   
     
     
         8 . The steam turbine system of  claim 7 , wherein the nozzle is one of a plurality of nozzles in the nozzle stage axially upstream of the last bucket stage, and wherein each of the plurality of nozzles is pivotable about a respective axis. 
     
     
         9 . The steam turbine system of  claim 7 , wherein the nozzle is pivotable about an axis substantially perpendicular with a primary axis of the rotor body. 
     
     
         10 . The steam turbine system of  claim 7 , wherein the nozzle is pivotable about an axis substantially parallel with a primary axis of the rotor body. 
     
     
         11 . The steam turbine system of  claim 7 , wherein the nozzle is pivotable at an angle of approximately 30 degrees. 
     
     
         12 . The steam turbine system of  claim 7 , wherein the nozzle includes a blade having:
 a first segment; and   a second segment operably connected to the first segment along the axis,   wherein the first segment is configured to pivot relative to the second segment about the axis.   
     
     
         13 . The steam turbine system of  claim 7 , wherein the predetermined load condition is a low part load condition or a high condenser pressure condition. 
     
     
         14 . A low pressure steam turbine apparatus comprising:
 a diffuser section;   a turbine coupled to the diffuser section, the turbine including:
 a rotor having:
 a rotor body; and 
 a plurality of bucket stages disposed axially along the rotor body, the plurality of bucket stages including a last bucket stage; and 
 
   a stator substantially surrounding the rotor, the stator including:
 a nozzle assembly at least partially surrounding the rotor, the nozzle assembly including a plurality of nozzle stages corresponding to the plurality of bucket stages, 
 wherein a nozzle in a nozzle stage axially upstream of the last bucket stage is adjustable to modify a fluid flow within the last bucket stage or the diffuser during operation of the steam turbine. 
   
     
     
         15 . The low pressure steam turbine apparatus of  claim 14 , wherein the nozzle is one of a plurality of nozzles in the nozzle stage axially upstream of the last bucket stage, and wherein each of the plurality of nozzles is pivotable about a respective axis. 
     
     
         16 . The low pressure steam turbine apparatus of  claim 14 , wherein the nozzle is pivotable about an axis substantially perpendicular with a primary axis of the rotor body. 
     
     
         17 . The low pressure steam turbine apparatus of  claim 14 , wherein the nozzle is pivotable about an axis substantially parallel with a primary axis of the rotor body. 
     
     
         18 . The low pressure steam turbine apparatus of  claim 14 , wherein the nozzle is pivotable at an angle of approximately 30 degrees. 
     
     
         19 . The low pressure steam turbine apparatus of  claim 14 , wherein the nozzle includes a blade having:
 a first segment; and   a second segment operably connected to the first segment along the axis,   wherein the first segment is configured to pivot relative to the second segment about the axis.   
     
     
         20 . The low pressure steam turbine apparatus of  claim 14 , wherein the nozzle is adjacent to the last stage bucket.