Apparatus and methods for cooling slot step elimination

Abstract

An airfoil core die includes a tab for forming a continuous and smooth contour and extension of a first trailing edge slot recessed all to a bottom of the airfoil. The contour is formed on each airfoil core at injection and is maintained through to finish casting of the airfoil.

1. A turbine blade for a turbine engine, said turbine blade comprising:
 an airfoil comprising a first side wall comprising an outer surface, a second side wall, a leading edge, and a trailing edge, said first side wall outer surface extending between said leading edge and said trailing edge, and trailing edge positioned between said first side wall and said second wall, said first side wall further comprising at least one slot defined by a recessed wall and a slot side wall, said slot side wall comprising an opening extending therethrough, said recessed wall extending between said opening and said trailing edge;  
 a platform connected to said airfoil; and  
 a fillet connected to said airfoil and said platform, at least a portion of said recessed wall extending to said fillet, said recessed wall tapered  is formed integrally with said airfoil during a casting process such that said recessed wall tapers from said opening to said fillet.  
 
     
     
       2. An airfoil in accordance with  claim 1  further comprising a first ledge extending between said outer surface and said recessed wall, said first ledge separated from said trailing edge by a distance. 
     
     
       3. An airfoil in accordance with  claim 2  wherein at least a portion of said recessed wall is positioned between said first ledge and said trailing edge. 
     
     
       4. An airfoil in accordance with  claim 2  further comprising a second ledge extending between said outer surface and said recessed wall. 
     
     
       5. An airfoil in accordance with  claim 4  wherein said second ledge extends between said opening and said trailing edge. 
     
     
       6. A method for fabricating an airfoil of a turbine blade, said method comprising the steps of:
 inserting a mold within a die; and  
 injecting a slurry into the die to form an airfoil that includes a first side including an outer surface, a second side, a leading edge, and a trailing edge, the first side outer surface extending between the leading edge and the trailing edge, the trailing edge positioned between the first side and the second side, the first side further including at least one slot defined by a recessed wall and a slot tide wall, the slot side wall including an opening extending therethrough, the recessed wall extending between the opening and the trailing edge and tapered form the opening to the first side outer surface.  
 
     
     
       7. A method in accordance with  claim 6  further comprising the step of attaching the airfoil to a platform. 
     
     
       8. A method in accordance with  claim 7  wherein said step of attaching the airfoil to a platform further comprises the step of extending a fillet form the leading edge to the trailing edge to secure the airfoil to the platform. 
     
     
       9. A method in accordance with  claim 8  wherein the airfoil is formed such that the first side slot is further defined by a second side wall, the second side wall extending from the opening to the trailing edge. 
     
     
       10. A method in accordance with  claim 9  wherein the airfoil is formed such that the recessed wall is tapered from the opening to the fillet. 
     
     
       11. An airfoil core for a turbine blade, said core comprising:
 at least one serpentine channel;  
 a wedge channel connected to said serpentine channel;  
 a plurality of fingers extending form said wedge channel; and  
 a tab extending from one of said fingers.  
 
     
     
       12. An airfoil core in accordance with claim  1    11  wherein said plurality of fingers includes a first finger, said tab located at said first finger and extending substantially perpendicular to said first finger. 
     
     
       13. An airfoil core in accordance with claim  1    11  wherein said at least one serpentine channel includes a first serpentine channel and a second serpentine channel.