Turbine nozzle with integral impingement blanket

Abstract

A turbine nozzle segment includes: (a) an arcuate outer band segment; (b) a hollow, airfoil-shaped turbine vane extending radially inward from the outer band segment; (c) a manifold cover secured to the outer band such that the manifold cover and the outer band segment cooperatively define an impingement cavity; and (d) an impingement blanket disposed in the impingement cavity, the impingement blanket having at least one impingement hole formed therethrough which is arranged to direct cooling air at the outer band segment. A method is provided for impingement cooling the outer band segment.

1 . A turbine nozzle segment comprising:
 (a) an arcuate outer band segment;   (b) a hollow, airfoil-shaped turbine vane extending radially inward from the outer band segment;   (c) a manifold cover secured to the outer band such that the manifold cover and the outer band segment cooperatively define an impingement cavity; and   (d) an impingement blanket disposed in the impingement cavity, the impingement blanket having at least one impingement hole formed therethrough which is arranged to direct cooling air at the outer band segment.   
   
   
       2 . The turbine nozzle segment of  claim 1  wherein the impingement blanket has a plurality of impingement holes formed therein. 
   
   
       3 . The turbine nozzle segment of  claim 1  wherein:
 (a) the manifold cover has a radially-inwardly facing recess formed therein, and (b) the impingement blanket comprises a plate which is secured to the manifold cover so as to close off the recess.   
   
   
       4 . The turbine nozzle segment of  claim 3  wherein the impingement blanket is brazed to the manifold cover. 
   
   
       5 . The turbine nozzle segment of  claim 1  wherein the manifold cover is brazed to the outer band segment. 
   
   
       6 . The turbine nozzle segment of  claim 1  wherein the manifold cover includes a radially-outwardly extending inlet tube. 
   
   
       7 . The turbine nozzle segment of  claim 1  further comprising an arcuate inner band segment disposed at a radially inner end of the turbine vane. 
   
   
       8 . A turbine nozzle assembly for a gas turbine engine, comprising:
 (a) a plurality of turbine nozzle segments arranged in an annular array, each turbine nozzle segment comprising:
 (i) an arcuate outer band segment; 
 (ii) a hollow, airfoil-shaped turbine vane extending radially inward from the outer band segment; 
 (iii) a manifold cover secured to the outer band such that the manifold cover and the outer band segment cooperatively define an impingement cavity; and 
 (iv) an impingement blanket disposed in the impingement cavity, the impingement blanket having at least one impingement hole formed therethrough which is arranged to direct cooling air at the outer band segment; 
   (b) an annular supporting structure surrounding the turbine nozzle segments; and   (c) a plurality of generally cylindrical conduits, each conduit connecting one of the manifold covers in independent flow communication with the supporting structure.   
   
   
       9 . The turbine nozzle assembly of  claim 8  wherein each of the impingement blanket has a plurality of impingement holes formed therein. 
   
   
       10 . The turbine nozzle assembly of  claim 8  wherein:
 (a) each of the manifold covers has a radially-inwardly facing recess formed therein, and   (b) each of the impingement blankets comprises a plate which is secured to the respective manifold cover so as to close off the recess.   
   
   
       11 . The turbine nozzle assembly of  claim 10  wherein each of the impingement blankets is brazed to the respective manifold cover. 
   
   
       12 . The turbine nozzle assembly of  claim 8  wherein each of the manifold covers is brazed to the respective outer band segment. 
   
   
       13 . The turbine nozzle assembly of  claim 8  wherein each of the manifold covers includes a radially-outwardly extending inlet tube to which the respective conduit is connected. 
   
   
       14 . The turbine nozzle assembly of  claim 8  further comprising an arcuate inner band segment disposed at a radially inner end of each of the turbine vanes. 
   
   
       15 . A method of cooling a turbine nozzle which includes an array of nozzle segments each having an arcuate outer band with a hollow, airfoil-shaped turbine vane extending radially inward therefrom, the method comprising:
 (a) providing each of the outer bands with a closed impingement cavity having an impingement blanket disposed therein;   (b) directing cooling air separately into the impingement cavities;   (c) directing cooling air through one or more impingement holes in the impingement blanket against the outer band; and   (d) exhausting the cooling air from the impingement cavity.