ガスタービン翼後縁部ディンプル付きカットバック面上フィルム冷却流の2次元3成分PTV計測

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, the turbulent flow over the dimpled cutback surface is experimentally examined aiming at heat transfer enhancement without disturbing the cooling film. Three types of dimples (spherical, teardrop, and 45deg angled teardrop) were examined by using two-dimensional three-component particle tracking velocimetry (2D3C-PTV). Reynolds number of the main flow was 18,000, and blowing ratio was varied from 0.5 to 2.0. In the spherical dimple case, flow separation and reattachment occurred at the leading and trailing edges of the dimple, respectively. On the contrary, flow separation was suppressed in the teardrop dimple case. In the 45deg angled teardrop dimple case, secondary flow in the dimple was observed in addition to the flow separation and flow reattachment at the leading and trailing edges. The effects of blowing ratio on the turbulent statistics were also discussed.
2013-11-20