Investigation Of Film Cooling Characteristics With One Inlet And Double Outlet Flat Plate Hole Injection

At present, film cooling is widely used for the aero engine turbine blade. The main factors which affected the film cooling characteristics are the aerodynamic parameters and geometric parameters. The method of improving film cooling hole-shape was mainly used by many domestic and foreign scholars. For this reason, this paper put forward a novel film cooling hole: one inlet and double outlet hole which was composed of two cylindrical holes.The film cooling characteristics of a novel hole was mainly studied by numerical simulation. The Navier-Stokes equations were solved by Fluent6.3 software with the realizable k -εmodel and enhanced wall function. The film cooling characteristics were studied at the blowing ratios of 0.5, 1.0, 1.5, 2.0 and at the orientation angle of 30°, 45°, 60°. The effects of the different turbulence intensities and density ratios on the film cooling characteristics were studied. The following conclusions were obtained:For the film cooling effectiveness, the results showed that the orientation angle had significant influences on the film cooling effectiveness. The optimal geometry of the hole was found at the orientation angle of 45°as the same as the high temperature calculations. The blowing ratios, density ratios and turbulence had significant influences on the film cooling effectiveness. The highest film cooling effectiveness of the orientation angle of 45°was obtained at the blowing ratio of 2.0.For the heat transfer coefficient, the results showed that the blowing ratios and turbulence intensity had influences on the heat transfer coefficient. Heat transfer coefficient between the mainstream and the wall was enhanced with the increase of blowing ratios. Influence of small turbulence intensity on heat transfer coefficient was weak, but the heat transfer was enhanced at the big turbulence intensity.For the discharge coefficient, the results showed that the discharge coefficient decreased with the increase of the orientation angle, but increased with the increase of blowing ratios. The turbulence intensity had no influences on the discharge coefficient.The film cooling effectiveness and heat transfer coefficient under the various hole-shapes and the various flow fields downstream of film hole were analyzed. The most fundamental reason to improve film cooling effectiveness was to improve the flow fields near the film holes.