Systematic Study of Film Cooling With a Three-Dimensional Calculation Procedure

The present paper describes three-dimensional calculations of film cooling by injection from a single row of holes. A systematic study of the influence of different parameters on the cooling effectiveness has been carried out. Twenty-seven test cases have been calculated, varying the injection angle (α = 10/45/90 deg), the relative spacing (s/D = 1.5/3/5) and the blowing rate (M = 0.5/1/2) for the same mainstream conditions. The governing three-dimensional equations are solved by a finite volume method. The turbulent stresses and heat fluxes are obtained from a k–ε model modified to account for nonisotropic eddy viscosities and diffusivities. Examples of predicted velocity and temperature distributions are presented and compared with available experimental data. For all the test cases, the laterally averaged cooling effectiveness is given. On the whole, the agreement with experiments is fairly good, even though there are discrepancies about details in some of the cases. The influence of the individual parameters on the film cooling effectiveness is predicted correctly in all cases. This influence is discussed in some detail and the parameter combination with the best overall cooling performance is identified.