Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Mechanical Power Engineering

The present study investigates the performance of film cooling on trailing edge of gas turbine blades using unsteady three-dimensional numerical model adopting Large Eddy Simulation (LES) turbulence scheme in low Mach number flow regime. The model concerns studying the scaling parameters affecting the effectiveness and heat transfer performance on the trailing edge of the gas turbine blades which is one of the most critical portions of the blade. LES turbulence model is employed with high quality meshing whereas the size of meshes adjacent to the wall is optimized carefully to sufficiently resolve the boundary layer to obtain insight predictions of the film-cooling effectiveness on a flat plate downstream the slot opening. Blowing ratio, density ratio, Reynolds number and the turbulence intensity of the mainstream and coolant flow are optimally examined against the film-cooling effectiveness. Nevertheless, the lip thickness is investigated as well. The predicted results when compared to previous study, they showed a great agreement with the experimental results. The results show a distinctive behavior of the cooling effectiveness with blowing ratio variation that there is a dip in the effectiveness in vicinity of unity. The negative effect of the turbulence intensity on the cooling effectiveness is demonstrated as well. An enhancement in cooling effectiveness is noticeably acquired by reducing the slot lip thickness

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