Numerical Investigation of the Flow Field in a Turbine Cascade With Different Film Cooling Holes at the Leading Edge

Flow structures in a turbine cascade with film cooling injections at the blade leading edge are investigated numerically for three cooling models of slots, straight cylindrical and spanwise inclined cylindrical holes under various blowing ratios, 0, 0.5, 0.7, 1.1, and 1.5. The numerical simulations are well compared with experiment results of static pressure and oil film visualization of blade surfaces. Discussions are mainly focused on the 3D flow structures within a blade passage. The results show that the 3D flow and energy loss production is greatly affected by the cooling injections, especially near the blade pressure surface.