The Effect of Hot Streaks on a High Pressure Turbine Vane Cascade with Showerhead Film Cooling

Hot streak migration in a linear vane cascade with showerhead film cooling was experimentally and numerically investigated at isentropic exit Mach number of Ma2is = 0.40, with an inlet turbulence intensity level of Tu1 = 9%. Two tangential positions of the hot streak center were taken into account: 0% of pitch (hot streak is aligned with the vane leading edge) and 45% of pitch. After demonstrating that computations correctly predict hot streak attenuation through the vane passage with no showerhead blowing, the numerical method was used to investigate hot streak interaction with showerhead film cooling, at blowing ratio of BR = 3.0, corresponding to a coolant-to-mainstream mass flow ratio of MFR = 1.15%. The effects of mixing and coolant interaction on the hot streak reduction were interpreted under the light of the superposition principle, whose accuracy was within 12% on the leading edge region, in the central section of the vane span.