Method and a system for adjusting nozzle area in steam turbines

Abstract

The various embodiments herein provide a method and a system for controlling a nozzle area in a steam turbine. The system comprises a nozzle ring provided with a plurality of nozzle blades at an outer edge. The steam enters into the nozzle ring and jets out on the blades of the rotor disk. When there is an off design condition, the nozzle blades are plugged or opened by adding or removing the inserts. The nozzle area is increased or decreased by opening or plugging the nozzle passages manually or automatically with the help of the inserts. The embodiments herein provide a cost effective and simple solution to deal with the off design conditions.

What is claimed is: 
     
         1 . A system for adjusting a nozzle area in a steam turbine comprising:
 a nozzle ring;   a plurality of nozzle blades provided in the nozzle ring; and   an insert to block a nozzle passage formed between two adjacent nozzle blades in the plurality of nozzle blades;   wherein the insert block the nozzle passages to control a flow of a driving fluid during an off-design condition.   
     
     
         2 . The system according to  claim 1 , wherein the nozzle passages are plugged by the inserts manually to decrease a nozzle area, and wherein the nozzle passages are plugged by the inserts manually to decrease a nozzle area in a full admission turbine or in a partial admission turbine. 
     
     
         3 . The system according to  claim 1 , wherein the inserts are removed from the nozzle passages manually to increase a nozzle area, and wherein the inserts are removed from the nozzle passages manually to increase a nozzle area in a full admission turbine or in a partial admission turbine. 
     
     
         4 . The system according to  claim 1 , wherein a number of nozzle passages are blocked by inserting the inserts based on a demand of the driving fluid in an off-design condition, and wherein a reduction or a variation in a demand of a driving fluid is caused in the off-design condition. 
     
     
         5 . The system according to  claim 1 , wherein the inserts are provided with a socket head screw to hold the inserts to the nozzle ring. 
     
     
         6 . The system according to  claim 1 , wherein the inserts are designed to fit with a contour of the nozzle passage. 
     
     
         7 . The system according to  claim 1 , wherein the insert is made up of stainless steel. 
     
     
         8 . The system according to  claim 1 , wherein the driving fluid is steam. 
     
     
         9 . The system according to  claim 1 , wherein the nozzle ring is aligned behind a turbine rotor disk. 
     
     
         10 . The system according to  claim 1 , wherein the nozzle ring is bolted to an inlet manifold of a turbine assembly. 
     
     
         11 . The system according to  claim 1 , wherein the nozzle blades are provided at an outer edge of the nozzle ring. 
     
     
         12 . The system according to  claim 1 , wherein the nozzle blades are made up of stainless steel. 
     
     
         13 . A method of controlling driving fluid in turbine during off-design condition, the method comprises:
 mounting and aligning a nozzle ring behind a turbine rotor disk;   selecting a number of nozzle passages to be blocked in the nozzle ring; and   blocking the selected number of nozzle rings by clamping inserts into a the respective nozzle passages;   wherein the selected number of nozzle passages are blocked by the inserts to control a flow of a driving fluid based on a demand in an off-design condition, and wherein a number of nozzle passages are blocked by inserting the inserts based on a demand of the driving fluid in an off-design condition, and wherein a reduction or a variation in a demand of a driving fluid is caused in the off-design condition.   
     
     
         14 . The method according to  claim 13 , wherein the nozzle passages are plugged by the inserts manually to decrease a nozzle area, and wherein the nozzle passages are plugged by the inserts manually to decrease a nozzle area in a full admission turbine or in a partial admission turbine. 
     
     
         15 . The method according to  claim 13 , wherein the inserts are removed from the nozzle passages manually to increase a nozzle area, and wherein the inserts are removed from the nozzle passages manually to increase a nozzle area in a full admission turbine or in a partial admission turbine 
     
     
         16 . The method according to  claim 13 , wherein the inserts are provided with a socket head type screw head to hold the inserts to the nozzle ring. 
     
     
         17 . The method according to  claim 13 , wherein the inserts are designed to fit with a contour of the nozzle passage. 
     
     
         18 . The method according to  claim 13 , wherein the nozzle ring is bolted to an inlet manifold of a turbine assembly. 
     
     
         19 . The method according to  claim 13 , wherein the insert is made up of stainless steel. 
     
     
         20 . The method according to  claim 13 , wherein the driving fluid is steam.