Relative Contributions to Overall Effectiveness in Gas Turbine Cooling
Gas turbine engine hot gas path components are protected via coolant that travels through internal passageways before being ejected as external film cooling. Efforts aimed at improving cooling are often focused on either only the internal cooling or the film cooling; however, the common coolant flow means the internal and external cooling schemes are inextricably linked and the coolant holes themselves provide another convective path for heat transfer to the coolant. The relative influence on the overall effectiveness of internal cooling, external cooling, and convection through the film cooling holes is not well understood. Large scale, matched Biot number experiments and computational fluid dynamics simulations were performed to isolate each cooling component, and thereby determine their relative effectiveness.