Combustor heat shield and method of cooling

Abstract

A heat shield for a gas turbine engine combustor includes an apparatus for providing a spiral flow to improve at least the cooling of the heat shield.

1 . A gas turbine engine combustor comprising a liner enclosing a combustion chamber and a heat shield mounted inside the liner and spaced apart therefrom to define an air space between the liner and the heat shield, the liner and heat shield each having at least one opening defined therein cooperating to respectively receive a fuel nozzle, the heat shield further comprising a plurality of cooling holes defined around the at least one opening in the heat shield, the cooling holes adapted to direct air from the air space through the heat shield in a spiral around an axis of the at least one opening in the heat shield.  
   
   
       2 . The combustor of  claim 1  wherein the heat shield opening axis is generally aligned with a fuel injection axis of the fuel nozzle.  
   
   
       3 . The combustor of  claim 1  wherein the cooling holes are restricted to a region immediately adjacent the heat shield opening.  
   
   
       4 . The combustor of  claim 1  wherein the cooling holes are disposed substantially circumferentially around the heat shield opening.  
   
   
       5 . The combustor of  claim 1  wherein the cooling holes are disposed concentrically around the axis.  
   
   
       6 . The combustor of  claim 1  wherein the cooling holes are disposed in a plurality of rows around the heat shield opening.  
   
   
       7 . The combustor of  claim 6  wherein the rows are concentric with one another.  
   
   
       8 . The combustor of  claim 1  wherein the heat shield includes a region wherein at least some cooling holes associated with a first opening are interlaced with at least some cooling holes associated with a second fuel nozzle opening in the heat shield.  
   
   
       9 . The combustor of  claim 1  wherein the heat shield includes a region wherein at least some cooling holes associated with the opening are interlaced with a second set of cooling holes, said second set of cooling holes adapted to direct a non-spiralling flow of air through the heat shield.  
   
   
       10 . The combustor of  claim 1  wherein the cooling holes are angled to direct air through the heat shield generally tangentially relative to the opening.  
   
   
       11 . A heat shield for a gas turbine engine combustor, the heat shield comprising a heat shielding member having at least one fuel nozzle opening defined therein and means for directing cooling air through the heat shielding member in a spiral pattern around an axis of the opening.  
   
   
       12 . The heat shield of  claim 11  wherein the means for directing comprises means for directing said cooling air generally tangentially relative the opening.  
   
   
       13 . The heat shield of  claim 11  wherein the means for directing is disposed substantially around the opening.  
   
   
       14 . The heat shield of  claim 11  wherein the means for directing is located concentrically with the opening.  
   
   
       15 . The heat shield of  claim 11  wherein the means for directing is disposed substantially perpendicularly to the axis.  
   
   
       16 . The heat shield of  claim 11  wherein the means for directing is provided in a generally planar portion of the heat shield.  
   
   
       17 . A method of cooling a gas turbine combustor heat shield, the method comprising the steps of: 
 directing air to a cool side of the heat shield; and    directing said air through the heat shield in a spiral around an axis of a fuel nozzle opening in the heat shield.    
   
   
       18 . The method of  claim 17  wherein said air is directed through the heat shield immediately adjacent the opening.  
   
   
       19 . The method of  claim 17  wherein said air is directed through the heat shield generally concentrically around the opening.  
   
   
       20 . The method of  claim 17  wherein the step of directing comprises directing air through the heat shield in a direction generally tangential to the opening.