Computational predictions of aero-thermal performance of a turbine filleted blade cascade with endwall film cooling

In this study computational fluid dynamic simulations of a turbine blade with endwall film cooling were compared to measurements of both aerodynamic and thermal performance. The experimental data were collected at low Mach number (Ma2is = 0.3) in a linear cascade arrangement with 7 blades which geometry is typical of first stage high pressure turbine. A junction between the blade hub and the platform is provided by a 3D fillet. Coolant is injected through ten cylindrical holes distributed along the blade pressure side. Coolant to mainstream mass flow ratio was set to assure an inlet blowing ratio of M1 = 2.4 and M1 = 3.2. The simulations were carried out using the Shear Stress Transport (SST) k-turbulence model. Numerical predictions were compared against experimentally measured secondary flows and endwall film cooling effectiveness, at different injection conditions. Simulation results agreed with the experiments for what concerns the general shape and the location of secondary flows. However, some limitations in the modeling were highlighted when going into the details of loss computation and vortex structure. Predictions overestimated both secondary and midspan blade wake losses. Moreover, the effect of the fillet on the aerodynamic flow features was not fully captured. Predicted film cooling results showed the sweeping of coolant across the passage in agreement with experiments even though jets persistency was higher than that measured. Levels of adiabatic effectiveness were generally well simulated.