Numerical modeling and simulation of flows characteristic of gas turbine blades

This research examines various aspects of fluid flow that are characteristic of those occurring in gas turbine engines. The hydrodynamics and heat transfer characteristics due to the injection of jets of coolant fluids into a hot mainstream are examined numerically. Various injection geometries are investigated, and correlations obtained for the application of an existing two-dimensional film cooling model. Possible approaches to the extension of this model to account for surface curvature are also investigated.; A new two-dimensional film cooling model is developed for the film cooling process. The model comprises an injection portion to account for the addition of mass, momentum, and energy by the jet, and a dispersion portion to account for the lateral entrainment.; Surface roughness can significantly affect the heat transfer and the skin friction characteristics of gas turbine flows. The discrete element method, which attempts to give a physical basis for the modeling of this effect, is incorporated into the Patankar-Spalding scheme of solution of the boundary layer equations.; Accurate accounting of variable property effects is critical to the computation of gas turbine flows. A new formulation of the boundary layer equations for the wall boundary condition of a specified heat flux is presented that does not require the prior knowledge of fluid properties at the wall. The Keller box method is used to solve the resulting set of governing equations.; The specification of accurate initial profiles is necessary to accurately predict transition to turbulence using two-dimensional boundary layer codes. The method of parameterized residuals is used to solve the form of the variable property boundary layer equations applicable in the stagnation flow region of gas turbine blades, to obtain initial profiles. This method is also applicable in the specification of initial profiles for natural convection.; In conclusion, the present work represents progress in the two-dimensional numerical computation of gas turbine flows. The performance of an existing film cooling model is assessed, and possible extensions to curved surfaces explored. A new two-dimensional film cooling model is developed using heuristic considerations that is demonstrated to show improved performance over a broad range of flow parameters. A physically meaningful model of flow over rough surfaces is incorporated into the Patankar-Spalding solution procedure for the boundary layer equations. A new formulation of the fully variable property boundary layer equations is proposed for the case of a wall heat flux. Finally, a solution procedure for variable property boundary layer equations is developed that can be used to specify accurate initial profiles for boundary layer codes, facilitating more accurate predictions of transition to turbulence.