Methods and apparatus for cooling combustion turbine engine components

TLDR: In this paper, a turbine nozzle cooling sub-system is provided, which includes at least one turbine nozzle segment and a diffuser wall, and the diffuser is coupled to the endwalls.

Abstract: A turbine nozzle cooling sub-system is provided. The sub-system includes at least one turbine nozzle segment. The segment includes an arcuate, radially outermost endwall, an arcuate, radially innermost endwall, and at least one airfoil vane. The endwalls each include at least one open passage. The airfoil vane extends between and is coupled to the endwalls. The vane further includes a cavity, a leading edge, a trailing edge, and an airfoil vane external surface. The cavity includes an airfoil vane internal surface and a plurality of turbulators. The cavity and the open passages are in flow communication such that an airfoil cooling air stream flow is facilitated. The sub-system also includes at least one diffuser in flow communication with a compressor assembly and the segment. The diffuser includes at least one diffuser wall and cavity. The diffuser wall extends from the compressor assembly to the segment such that a channeling of the airfoil cooling air stream to the segment is facilitated. The airfoil cooling air stream includes at least a portion of a compressor assembly discharge air stream flow.