Effect of Crossflows on the Discharge Coefficient of Film Cooling Holes With Varying Angles of Inclination and Orientation

Measurements of discharge coefficients for five configurations of cylindrical film cooling hole geometries are presented. These comprise holes of varying angles of inclination (α=30, 45, and 90 deg) and orientation (γ=0, 45, and 90 deg), which are tested over a wide range of engine-like conditions in terms of internal and external crossflow Mach numbers (Mam=0…1.2,Mac=0…0.6) as well as pressure ratios ptc/pm=1…2.25. Results show that discharge coefficients do not depend solely on hole geometry, but are also profoundly affected by the internal and external crossflow conditions. The effect of increasing the orientation angle on the discharge behavior is very similar to the effect of increasing the inclination angle. Both result in higher losses, particularly at the cooling hole inlet while the losses at the hole exit are only slightly affected.