Film cooling performance for injection through discrete holes in the e
ndwall of a turbine blade is investigated. The effectiveness is measur
ed at 60 locations in the region covered by injection. Three nominal b
lowing rates, two density ratios, and two approaching flow Reynolds nu
mbers are examined. Analysis of the data reveals that even 60 location
s are insufficient for the determination of the field of film cooling
effectiveness with its strong local variations. Visualization of the t
races of the coolant jets on the endwall surface, using ammonium-diazo
-paper, provides useful qualitative information for the interpretation
of the measurements, revealing the paths and interaction of the jets,
which change with blowing rate and density ratio.