Film Cooling Effectiveness Measurements With Periodic Unsteady Inflow on Highly Loaded Blades With Main Flow Separation

Abstract

Film cooling experiments were performed using a highly loaded HPT blade linear cascade. A large region with main flow separation is found on the pressure side and film cooling is provided into this area with three rows of either cylindrical or fan-shaped holes. The measurements comprise adiabatic film cooling effectiveness and profile static pressure measurements. The surface temperature was acquired with thermochromatic liquid crystals and using a hue to temperature correlation. The results shown are for variations of main flow Mach and Reynolds numbers at engine relevant levels and of coolant mass flows. The results for steady and periodic unsteady inflow with highly turbulent wakes created by cylindrical bars moving upstream in a plane parallel to the cascade are compared as two-dimensional surface plots, laterally averaged film cooling effectiveness and overall effectiveness over the entire surface.