Inlet Turbulence Intensity Effect on Endwall Film Cooling

The present paper reports on the effects of inlet turbulence intensity level on the aero-thermal performance of a film cooled endwall. The present investigation has been performed in a low speed linear vane cascade with a fan-shaped hole cooling geometry. Holes are arranged in four pitchwise rows, covering the flow passage. Two turbulence intensity levels have been investigated (1% and 9%). For each turbulence value, coolant to mainstream massflow ratio has been varied in the range 0.75 – 2.5%. Secondary flows 0.5cax downstream of the cascade have been surveyed by means of 5-holes aerodynamic probe. Local and overall secondary loss coefficient and vorticity distributions have been computed from measured data. The thermal behaviour has been also analyzed by using the wide banded TLC’s technique, so to obtain adiabatic effectiveness distributions on the endwall. Even if some differences in both aerodynamic and thermal results were observed locally, the overall secondary energy loss coefficient as well as the global pitch and axial averaged adiabatic effectiveness did not show significant variations.