ガスタービン翼後縁部ディンプル付きカットバック面フィルム冷却のLES解析 : ブロー比1でのディンプル形状の影響

概要

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Cooling at trailing edge of gas turbine airfoil is one of the most difficult problems because of its thin shape: high thermal load from both surfaces, hard-to-cool geometry of narrow passages, and at the same time demand for structural strength. In this study, both heat transfer coefficient and film cooling effectiveness on pressure-side cutback surface were numerically simulated by using Large Eddy Simulation with a dynamic Smagorinsky model. Three different cutback geometries were examined: smooth surface and two roughened cutback surfaces with spherical and teardrop dimples. The Reynolds number of the main flow defined by the mean velocity and two times of the channel height was 20,000 and the blowing ratio was at 1.0. The LES results were verified by the experimental results measured for the same geometry. Within the present experimental range, the teardrop-dimpled surface was the most favorable cutback-surface geometry, because it gave higher film cooling effectiveness and Nusselt number than the spherical-dimpled and smooth surfaces.
2014-01-20