Impact and Sensitivity of the Curvature of Turbine Cascades on the Film Cooling Effectiveness

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In this research project the influence of the curvature of the hub and casing on the secondary flow is to be examined with regard to the film cooling effectiveness. The investigations are performed for differnet parameters of the hub radius and for leakage flow. The impact of the curvature parameter is defined as the ratio of the chord length and the hub radius. The results make it possible to estimate the sensitivity of the curvature on the film cooling effectiveness. Such an investigation of the impact of the curvature by parameters have not been done until today. The sensitivity is defined as σ = d η_ad/d RN. σ is to be determined locally, i.e. for all points σ is determined by applying a central difference quotation of the corresponding CFD results of S/RN = 0.2 and 0.3. Additionally, the integral sensitivity is determined. Therefore, the sensitivity is averaged over the hub and casing surface. The project is performed by numerical and experimental methods, whereas the experimental investigations are restricted on one turbine cascade due to reducing the costs. The experimental results are used for the validation of the numerical model. The tests are performed for the cylindrical guide vanes of the NASA Energy Efficient Engine Program (E3) which was already investigated for its linear cascade.