3次元熱伝導を考慮した過渡応答法によるディンプル付きカットバック面のフィルム冷却性能評価 : 球状ディンプルと傾斜有無ティアドロップディンプルの比較

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, heat transfer experiments by using transient technique with compensation of three-dimensional heat conduction were performed for cutback surfaces with three types of dimples: spherical, teardrop-shaped without inclination, and 45deg angled teardrop-shaped dimples. The present results clearly showed the precise spatial distributions of film cooling effectiveness and Nusselt number. Although overall film cooling effectiveness was almost same among three types of dimpled cutback surfaces, overall Nusselt numbers of teardrop-shaped and 45deg angled teardrop-shaped cases were higher than the spherical case; the teardrop-shaped dimples without inclination gave slightly higher values both in film cooling effectiveness and Nusselt number than the 45deg angled teardrop-shaped case. As a result, net heat flux reduction of teardrop-shaped dimple without inclination was the highest among the cases examined.
公益社団法人日本ガスタービン学会の論文
2013-09-20