Abstract: The present invention provides a turbine blade having a revised under-platform structure including a unique coating combination that reduces mechanical stress factors within the turbine blade. The turbine blade includes a platform with an airfoil extending upwardly from the airfoil and a root portion extending downwardly from the platform. Two suction side tabs extend a first distance outward from a suction side of the root potion. Two pressure side tabs extend outward from a pressure side of the root portion. One of the two pressure side tabs extends outward a distance similar to the first distance, however, the other of the two pressure side tabs extends outward a distance much smaller than the first distance, which reduces stresses acting on the turbine blade. In addition, a plurality of coatings are systematically applied to the turbine blade to further reduce mechanical stress factors and improve cooling.

Abstract: The present invention provides an improved cooling circuit for a trailing edge of a turbine blade. The cooling circuit includes an inlet passage that receives a airflow and distributes the airflow through a feed passage. The feed passage primarily includes trip strips, at least one barrier including cross-over holes, teardrop shaped protrusions, and pockets disposed along a trailing edge. The geometry and positioning of both the cross-over holes and teardrop shaped protrusions downstream of the cross-over holes have been optimized to maximize cooling efficiency and reduce airflow. An improved transition between the inlet passage and the feed passage is also provided, which is arcuate and allows the airflow to maintain attachment and flow unimpeded from the inlet passage to the feed passage. The geometry of the pockets disposed along the trailing edge is optimized to improve cooling.