Experimental study of unsteady wake effect on a film-cooled pitchwise-curved surface

Unsteady wake interactions with the near wall flow field occur when a surface is exposed to fluid flow past upstream rotating bodies. In the case of gas turbines, understanding such interactions are essential to better design cooling schemes on endwalls. In view of this, an experimental study has been conducted to determine the heat transfer coefficient and film cooling effectiveness on a pitchwise-curved surface which is subjected to unsteady passing wakes generated using a wake rod in a wall-normal orientation. The mainstream Mach number was maintained approximately constant at 0.03. A single row of cylindrical film holes with pitch to diameter ratio of 3 and inclined at 35[degrees] to the test surface are used for discrete film injection. A combination of unsteady passing wakes and film injection resulted in a maximum pitch-averaged and centerline heat transfer augmentation of = 28% and 31.7% respectively.