Film Cooling Effectiveness on a Convex and Flat Surface in Conditions of Pulsed Blowing through Fan-Shaped and Cylindrical Holes

The study focuses on the effect of pulsed blowing on the film cooling effectiveness. Cylindrical and fan-shaped holes on a convex and flat surface are considered in this regard. The blowing angles of 30, 45, 75 deg are investigated. To analyze the obtained results, the action of centrifugal mass forces on a convex surface, diffuser-type effects in fan-shaped holes, and kinetic energy of thermal shield behind the blowing coordinate are considered. Depending on the examined conditions, the forced pulsation superimposed on the secondary flow are shown to either increase or decrease the effectiveness of thermal shield on the cooled surface.