Radial flow turbine wheel for a gas turbine engine

Abstract

A radial-flow turbine wheel for a gas turbine engine includes a Scallop Radius defined between an axis of rotation and the backface between each of the plurality of turbine blades, a Tip Radius defined between the axis of rotation and a tip of each of the plurality of turbine blades such that a Scallop Radius/Tip Radius defines a ratio less than 0.6. This enables a lower temperature scallop region which drives lower transient stresses and increases the Low Cycle Fatigue life of the turbine wheel.

1 . A radial-flow turbine wheel for a gas turbine engine comprising:
 a hub having a backface defined about an axis of rotation; and   a plurality of turbine blades formed around said hub at constant intervals to form a scallop in said backface, a Scallop Radius defined between said axis of rotation and said backface between each of said plurality of turbine blades, a Tip Radius defined between said axis of rotation and a tip of each of said plurality of turbine blades such that a Scallop Radius/Tip Radius defines a ratio less than 0.6.   
     
     
         2 . The radial-flow turbine wheel as recited in  claim 1 , wherein said scallop forms an inwardly concave shape within said backface. 
     
     
         3 . The radial-flow turbine wheel as recited in  claim 2 , wherein said scallop blends a rear edge of each of said plurality of turbine blades. 
     
     
         4 . The radial-flow turbine wheel as recited in  claim 1 , wherein said plurality of turbine blades extend from said backface. 
     
     
         5 . The radial-flow turbine wheel as recited in  claim 1 , wherein said Scallop Radius/Tip Radius defines a ratio of 0.55.