Effects of bulk flow pulsations on film cooling from different length injection holes at different blowing ratios

Bulk flow pulsations in the form of sinusoidal variations of velocity and s tatic pressure at injectant Strouhal numbers from 0.8 to 10.0 are investiga ted as they affect film cooling fram a single row of simple angle holes. Si milar flow variations are produced by potential. flow interactions and pass ing shock waves near turbine surfaces in gas turbine engines. Time-averaged temperature distributions, phase-averaged temperature distributions, adiab atic film cooling effectiveness values, and iso-energetic Stanton numbers s how that important alterations to film cooling protection occur as pulsatio n frequency, coolant Strouhal number, blowing ratio, and nondimensional inj ection hole length are changed. Overall, the pulsations affect film perform ance and behavior more significantly both as L/D decreases, and as blowing ratio decreases.