Method and apparatus for reducing axial compressor blade tip flow

Abstract

A turbine machine of the type having a high pressure compressor positioned in a casing is provided with a plurality of rotating compressor blades with at least one air channel formed in the blades for air flow communication from the base to the tip for extracting and pressurizing air from an inner area proximate the disk and conveying the extracted and pressurized air into an area between the blade tip and casing for blocking air flow across the tips of the blades.

1 . A turbine machine of the type having a high pressure compressor positioned in a casing, a plurality of rotating compressor blades having respective blade tips, respective blade bases affixed to a central disk, and a plurality of stationary vanes positioned between respective ones of the blades, comprising at least one air channel formed in respective ones of the blades for air flow communication from the base to the tip for extracting and pressurizing air from an inner area proximate the disk and conveying the extracted and pressurized air through the channel into an area between the blade tip and casing for blocking air flow across a tip of the blades.  
   
   
       2 . A turbine machine according to  claim 1 , wherein the channel exits the blade tip through a respective plurality of exit holes.  
   
   
       3 . A turbine machine according to  claim 1 , wherein the channel includes an air inlet opening in on leading edge side of the blade.  
   
   
       4 . A turbine machine according to  claim 1 , wherein the channel includes an air inlet opening on a trailing edge side of the blade.  
   
   
       5 . A turbine machine according to  claim 1 , wherein the channel includes an air inlet opening in on a leading edge side and an air inlet opening on a trailing edge side of the blade.  
   
   
       6 . A turbine machine according to  claim 1 , and including a first channel having an air inlet opening on a leading edge side of the blade and a second channel having an air inlet opening on a trailing edge side of the blade.  
   
   
       7 . A turbine machine according to claims  3 , wherein the channel includes a plurality of exit holes in the blade tip.  
   
   
       8 . A method of reducing air flow between a tip of a turbine airfoil rotating in a closely-spaced apart casing, comprising the steps of: 
 (a) providing in the airfoil a radially-extending channel having an inlet opening proximate a base of the airfoil and an exit opening on the airfoil tip;    (b) extracting and pressurizing air from a region proximate the base of the airfoil into the channel;    (c) conveying the air through the channel to the airfoil tip; and    (d) discharging the air through the exit openings in the airfoil tip into an area between the airfoil tip and casing under sufficient pressure to resist axial air flow across the tip of the airfoil.    
   
   
       9 . A method according to  claim 8 , wherein the step of providing a radially-extending channel having an inlet opening proximate a base of the airfoil and an exit opening on the airfoil tip includes the step of forming the inlet opening on a leading edge side of the airfoil.  
   
   
       10 . A method according to  claim 8 , wherein the step of providing a radially-extending channel having an inlet opening proximate a base of the airfoil and an exit opening on the airfoil tip includes the step of forming the inlet opening on a trailing edge side of the blade.  
   
   
       11 . A method according to  claim 8 , wherein the step of providing a radially-extending channel having an inlet opening proximate a base of the airfoil and an exit opening on the airfoil tip includes the steps of forming an air inlet opening on a leading edge side of the airfoil, and an air inlet opening on the trailing edge side of the airfoil.  
   
   
       12 . A method according to  claim 8 , including the steps of providing: 
 (a) a first radially-extending channel having an inlet opening proximate the base of the airfoil on the leading edge side thereof and an exit opening at the airfoil tip; and    (b) a second radially-extending channel having an inlet opening proximate the base of the airfoil on the trailing edge side thereof and an exit opening at the airfoil tip.    
   
   
       13 . A method of reducing air flow between a tip of a turbine airfoil rotating in a closely-spaced apart casing, comprising the steps of: 
 (a) providing a first radially-extending channel having an inlet opening proximate a base of the airfoil on a leading edge side thereof, and an exit opening on the airfoil tip;    (b) providing a second radially-extending channel having an inlet opening proximate the base of the tip on a trailing edge side thereof, and an exit opening on the airfoil tip;    (c) extracting high pressure air from a region proximate the base of the airfoil into the channels:    (d) conveying the air through the channels to the airfoil tip; and    (e) exiting the air through the exit openings in the airfoil tip into an area between the airfoil tip and casing under sufficient pressure to resist axial air flow across the tip of the airfoil.    
   
   
       14 . A turbine machine compressor blade, comprising: 
 (a) a blade base;    (b) a blade tip;    (c) an air flow channel extending radially from an air inlet opening in the blade proximate the blade base to an exit opening in the blade tip.    
   
   
       15 . A turbine machine compressor blade according to  claim 14 , wherein the air inlet opening is formed on a leading edge side of the blade.  
   
   
       16 . A turbine machine compressor blade according to  claim 14 , wherein the air inlet opening is formed on a trailing edge side of the blade.  
   
   
       17 . A turbine machine compressor blade according to  claim 14 , wherein the channel includes an air inlet opening on a leading edge side of the blade and an air inlet opening on a trailing edge side of the blade.  
   
   
       18 . A turbine machine compressor blade according to  claim 14 , and including a first channel having an air inlet opening on a leading edge side of the blade and a second channel having an air inlet opening on a trailing edge side of the blade.