Fundamental investigations of the heat transfer and the the turbulent flow in convection cooled gas turbine blades

效率最高的现代固定式燃气轮机的涡轮入口温度高达1500°C，而目前S燃气轮机使用的高温材料只能承受高达1000°C的温度。这种温差只能通过冷却热负荷部件，特别是涡轮叶片来克服。冷却空气从压缩机中带走，因此不能再用于涡轮第一级的燃烧和膨胀，因此，较高的冷却空气量会导致总效率的损失。本课题的目的是研究对流冷却燃气轮机叶片内的复杂流动和换热过程，其主要目的是提供一种耦合的实验和数值方法，该方法使用分段测量的冷却通道的积分换热，从而能够显著地提高换热预测的精度。因此，一个次要的目标是量化基于有限元方法的冷却通道内经典的换热关联式所引起的不确定性。因此，采用探头和热线穿越真实冷却通道几何形状的方法，测量了带有湍流段和弯道的进出流的流场和温度场。因此，可以研究湍流段的单个影响以及它们的串联。因此，通过简单几何形状的实验获得的经典关联式可以与实际冷却通道几何形状下的整体换热测量结果进行比较。另一个子目标是评估整个基于有限元的方法的能力，其中分段精确的换热关联式。在这个项目中，据我们所知，基于有限元的方法的所有三个部分都将在相同的条件下进行研究，因此具有直接可比性，并将在公开文献中发表：a)冷却空气试验台中冷却通道几何形状的准确测量，b)具有相应的传热关联式的基于有限元的方法，以及c)在真实温度条件下的验证。因此，不同组成部分的自然不同优势将被融合为一个完整的结果。

Modern stationary gas turbines with highest efficiencies reach turbine inlet temperatures up to 1500 °C whereas the used high temperature materials in today´s gas turbines tolerate only temperatures up to 1000 °C. This temperature difference can only be overcome by cooling of the thermally burdened parts, especially of the turbine blade.The cooling air is taken from the compressor and therefore can no longer be used for the combustion and the expansion in the first stages of the turbine, therefore a higher amount of cooling air leads to losses in the total efficiency. Hence it is necessary to reduce the cooling air flow and use it as efficient as possible.The aim of this project is the investigation of the complex flow and the heat transfer processes in a convection cooled gas turbine blade.The primary purpose of the submitted proposition is to provide a coupled experimental and numerical procedure which uses the integral heat transfer of the cooling channels measured in sections and enables a distinct enhancement of the prediction of the heat transfer.Therefore one sub-ordinate target is the quantification of the uncertainties which arise out of the application of classical heat transfer correlations inside the cooling channels of FEM based methods. Therefore the flow field and temperature field in the inflow and outflow of the section equipped with turbulators and the bends will be measured by traversing with probes and hot wires inside a real cooling channel geometry. Thus the single influences of the turbulated sections as well as their series connection can be investigated. So the classical correlations gained by experiments with simple geometries can be compared with integral heat transfer measurements in a real cooling channel geometry.Another sub-goal is to evaluate the ability of the whole FEM based method with section wise exact heat transfer correlations. Therefore the numerical results of the FEM based methods will be compared to experimental data gained at a hot gas cascade test rig under real engine conditions.In this project as far as we know for the first time all three parts of a FEM based methods will be investigated under the same conditions and are therefore directly comparable and will be published in the open literature: a) the exact measurement of a cooling channel geometry in the cooling air test rig, b) the FEM based method with the correspondent heat transfer correlations and c) the validation under real temperature conditions. Hence the naturally different strengths of the diverse components will be merged to an integral result.