INTERACTION OF FILM COOLING ROWS: EFFECTS OF HOLE GEOMETRY AND ROW SPACING ON THE COOLING PERFORMANCE DOWNSTREAM OF THE SECOND ROW OF HOLES

摘要

A comprehensive set of generic experiments is conducted to investigate the interaction of film cooling rows. Five different film cooling configurations are considered on a large scale basis each consisting of two rows of film cooling holes in staggered arrangement. The hole pitch to diameter ratio within each row is kept constant at P/D=4. The spacing between the rows is either x/D=10, 20, or 30. Fanshaped holes or simple cylindrical holes with an inclination angle of 30 deg. and a hole length of 6 hole diameters are used. With a hot gas Mach number of Ma{sub}m=0.3, an engine like density ratio of ρ{sub}c/ρ{sub}m=1.75, and a freestream turbulence intensity of Tu=5.1% are established. Operating conditions are varied in terms of blowing ratio for the upstream and, independently, the downstream row in the range 0.5