Future advanced turbine systems for electric power generation systems, based on coal-gasified fuels with CO2 capture and sequestration, are aimed for achieving higher cycle efficiency and near-zero emission. Most promising operating cycles being developed are hydrogen-fired cycle and oxy-fuel cycle. Both cycles will likely have turbine working fluids significantly different from that of conventional air-based gas turbines. In addition, the oxy-fuel cycle will have a turbine inlet temperature target at approximately 2030K (1760°C), significantly higher than the current level. This suggests that aerothermal control and cooling will play a critical role in realizing our nation’s future fossil power generation systems. This paper provides a computational analysis in comparing the internal cooling performance of a double-wall or skin-cooled airfoil to that of an equivalent serpentine-cooled airfoil. The present results reveal that the double-wall or skin cooled approach produces superior performance than the conventional serpentine designs. This is particularly effective for the oxy-fuel turbine with elevated turbine inlet temperatures. The effects of coolant-side internal heat transfer coefficient on the airfoil metal temperature in both hydrogen-fired and oxy-fuel turbines are evaluated. The contribution of thermal barrier coatings (TBC) toward overall thermal protection for turbine airfoil cooled under these two different cooling configurations is also assessed.

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