The disclosure relates generally to hot gas path (HGP) components, and more particularly, to a cooling structure for an HGP component and methods of fabricating the cooling structure.
In a turbine system, a “hot gas path” (HGP) component can generally include a nozzle, rotor blade, shroud, or other hardware used in a combustion section of a gas turbine. Stationary blades are a type of HGP component used in turbine applications to direct hot gas flows to moving rotor blades, also known as buckets, to generate power. In steam and gas turbine applications, the stationary blades are referred to as nozzles, and are mounted to an exterior structure such as a casing and/or an internal seal structure by endwalls. Each endwall is joined to a corresponding end of an airfoil of the stationary blade. Stationary blades can also include passages or other features for circulating cooling fluids which absorb heat from operative components of the turbomachine. The flow of operative fluids, e.g., hot gas, against the buckets can cause a shaft to rotate and thereby drive a generator operatively connected to the turbine section of the system.
In order to operate in extreme temperature settings, HGP components such as moving and stationary blades need to be cooled. In an example system, cooling fluids can be pulled from the wheel space or a dedicated source and routed into or through a cooling circuit of the blade to provide heat transfer between the composition of the blade and the cooling fluid. In contrast, in many gas turbine applications, later stage nozzles may be fed cooling fluid, e.g., air, extracted from a compressor of the gas turbine. In addition to the effectiveness of cooling, the structure of an HGP and cooling structures therein can affect other factors such as manufacturability, ease of inspection, and the durability of a turbomachine.