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

在本研究项目中，轮毂和机匣的曲率对二次流的影响将在薄膜冷却效率方面进行检查。对轮毂半径的不同参数和泄漏流进行了研究。曲率参数的影响被定义为弦长与轮毂半径的比值。计算结果可用来估计曲率对气膜冷却效率的敏感性。直到今天，还没有这样的调查的影响，曲率的参数。灵敏度定义为σ = d η_ad/d RN。σ应局部确定，即对于所有点，σ应通过应用S/RN = 0.2和0.3的相应CFD结果的中心差分报价来确定。此外，还确定了积分灵敏度。因此，灵敏度在轮毂和壳体表面上平均。该项目是通过数值和实验方法进行的，而实验研究仅限于一个涡轮机叶栅，以减少成本。实验结果被用于验证的数值模型。试验是针对NASA节能发动机计划（E3）的圆柱形导向叶片进行的，该计划已经对其线性叶栅进行了研究。

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.