Film cooling from a cylindrical hole with parallel auxiliary holes influences

ABSTRACTIn the present paper, numerical analysis has been performed to investigate the film-cooling performance of a cylindrical hole, cylindrical hole with upstream parallel auxiliary holes, cylindrical hole with downstream parallel auxiliary holes, and a cylindrical hole with both upstream and downstream parallel auxiliary holes. Four kinds of film-cooling holes are compared through Reynolds-averaged Navier–Stokes (RANS) analysis for four blowing ratios: 0.5, 1.0, 1.5, and 2.0. The result shows that the auxiliary holes enhance the film-cooling effectiveness. The cylindrical hole with upstream auxiliary holes is better for protecting the text surface than the cylindrical hole with downstream auxiliary holes. In general, the hole with both upstream and downstream parallel auxiliary holes shows the most effective film protection compared with the other three cases tested in this work, especially in blow ratios 0.5 and 1.0.