Time Resolved Film Cooling Flows at High and Low Density Ratios

Abstract

Filmcooling is one of the most prevalent cooling technologies that is used for gas turbine airfoil surfaces. Numerous studies have been conducted to give the cooling effectiveness over ranges of velocity, density, mass flux, and momentum flux ratios. Few studies have reported flowfield measurements with even fewer of those providing timeresolved flowfields. This paper provides timeaveraged and timeresolved particle image velocimetry data for a filmcooling flow at low and high density ratios. A generic filmcooling hole geometry with wide lateral spacing was used for this study, which was a 30 deg inclined round hole injecting along a flat plate with lateral spacing P/D = 6.7. The jet Reynolds number for flowfield testing varied from 2500 to 7000. The data indicate differences in the flowfield and turbulence characteristics for the same momentum flux ratios at the two density ratios. The timeresolved data indicate Kelvin–Helmholtz breakdown in the jettofreestream shear layer.