Prediction of heat-transfer characteristics for discrete hole film cooling on flat plate and turbine blades
A two-dimensional injection model for the discrete hole film cooling process is developed. The injection model is used with a low Reynolds number {kappa}-{epsilon} turbulence model to predict the spanwise averaged effectiveness and the heat transfer coefficient for a wide range of injection geometries and external flow conditions. The three-dimensional effect of discrete hole injection is introduced in the prediction scheme by developing the concept of entrainment fraction and entrainment enthalpy. The entrainment fraction is correlated with the injection parameter {chi} = U{sub j}sina{sub o}/U{sub e} and the pitch to diameter ratio of the holes, where U{sub j} is the jet velocity, U{sub e} is the local free stream velocity, and a{sub o} is the angle of injection. Predictions of injection into flat plate laminar and turbulent boundary layers, accelerating boundary layers, boundary layers over curved surfaces and injection into the stagnation region of a cylinder are tested with experimental data. Calculations are also compared with experiments for diffuser shaped holes and for multirow injection. In order to perform calculations for leading edge film cooling geometries, stagnation region flow over a cylinder is modeled within the framework of the {kappa}-{epsilon} turbulence model and extended to flow over turbine blades. A method is proposed to generate the initial profiles of velocity, temperature, turbulent kinetic energy and its dissipation rate. An additional source term, based on the strong streamwise velocity gradients, is incorporated in the decay equations of free stream turbulence. Predictions of the heat transfer coefficient are compared with experimental data for cylinders and airfoils.
- Research Organization:
- California Univ., Berkeley, CA (USA)
- OSTI ID:
- 6467306
- Resource Relation:
- Other Information: Thesis (Ph.D)
- Country of Publication:
- United States
- Language:
- English
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AIRFOILS
FILM COOLING
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990200* - Mathematics & Computers
200104 - Fossil-Fueled Power Plants- Components