Arrangement effects of inclined teardrop-shaped dimples on film cooling performance of dimpled cutback surface at airfoil trailing edge
Arrangement effects of inclined teardrop-shaped dimples on film cooling performance of dimpled cutback surface at airfoil trailing edge
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DOI：
10.1016/j.ijheatmasstransfer.2016.11.081
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发表时间：
2017-04
影响因子：
5.2
通讯作者：
A. Murata;Kohtaro Yano;M. Hanai;H. Saito;K. Iwamoto
中科院分区：
文献类型：
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作者：
A. Murata;Kohtaro Yano;M. Hanai;H. Saito;K. Iwamoto
燃气涡轮机翼型的后缘冷却是最困难的问题之一，因为它的薄形状：来自两个表面的高热负荷，狭窄通道的几何形状难以冷却，同时对结构强度的要求是原因。在这项研究中，传热系数和气膜冷却效率的压力侧削减表面上的瞬态红外热成像技术进行了测量，考虑到三维热传导。通过泪滴形凹痕使截短表面粗糙化。三个不同的旋转角度（30，45，和60度）的酒窝表面与线和交错安排进行了检查的吹气比为0.5，1.0，1.5，和2.0。在目前的安排，薄膜冷却效率几乎保持不变，虽然传热系数成为最大值在30度的直线排列。通过净热通量减少评估的整体膜冷却性能对于30 °直列布置是最高的，并且比30 °交错布置高14-24%。三分量PTV结果通过30 °顺列布置中流动分离的抑制解释了这种效应，并且在下游凹坑处获得了有利的来流条件。
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 are the reasons. In this study, heat transfer coefficient and film cooling effectiveness on pressure-side cutback surface were measured by a transient infrared thermography technique with consideration of three-dimensional heat conduction. The cutback surface was roughened by teardrop-shaped dimples. Three different rotation angles (30, 45, and 60 deg) of the dimpled surface with in-line and staggered arrangements were examined for blowing ratio of 0.5, 1.0, 1.5, and 2.0. Within the present arrangements, the film cooling effectiveness remained almost constant, although the heat transfer coefficient became a maximum at 30 deg in-line arrangement. The overall film cooling performance evaluated by net heat flux reduction was the highest for the 30 deg in-line arrangement and it was 14–24% higher than the 30 deg staggered arrangement. Three-component PTV results explained this effect by the suppression of flow separation in the 30 deg in-line arrangement and it attained the favorable inflow condition on the downstream dimples.