Numerical prediction of cooling losses in a high-pressure gas turbine airfoil

Numerical investigations of the flow past a film-cooled nozzle guide vane cascade were conducted to determine the influence of coolant ejection on profile loss. The film cooling on the suction surface as well as the trailing edge bleeding was simulated at engine representative main flow Reynolds and Mach numbers, varying the coolant ejection rate. Experiments carried out in a high-speed wind tunnel provided a comprehensive test case to verify the capability of the numerical models to correctly reproduce the flow phenomena taking place in the vane passage. Results show that the main features of the flow, such as aerodynamic loading, flow separation, and loss distribution in the wake of the airfoil can be quite accurately predicted without excessive computational effort using a standard RANS SST model, which proved to be a reliable and more adequate alternative to the widely used models based on simple control volume analysis.