Effectiveness and Heat Transfer With Full-Coverage Film Cooling

Abstract

The paper presents experimental results for performance of full-coverage film cooled surfaces. Effectiveness and heat transfer are measured on plane surfaces with discrete injection through the surface at an array of points into a turbulent mainstream boundary layer. The injection is normal to the surface, through circular holes arranged in both in-line and staggered patterns with 4.8 hole diameters used for both the row-to-row spacing and the hole-to-hole spacing within a single row. Both the film and mainstream fluids are air, and property differences are kept small throughout the study. Uniform injection over the entire array at film-to-mainstream velocity ratios of 0.1 and 0.2 with a uniform wall temperature boundary condition are covered. Results are compared with predictions using superposition of available single hole local effectiveness values.