Experimental investigation of rotation number effect on film cooling over a convex surface
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摘要: 采用圆弧模型,测量了旋转状态下凸表面气膜冷却效率 η ad和换热系数 h f的分布规律,重点研究旋转数 Rt=ωD/u∞ 对气膜冷却的影响.叶片表面温度采用先进的液晶测温技术进行测量.结果表明:①在旋转离心力和哥氏力的共同作用下,气膜轨迹向高半径方向发生了明显的偏移,并且转速越高偏移角度越大;②旋转使得气膜冷却效率降低,换热系数上升;③在旋转状态下,气膜发生了分离再附壁的现象.Abstract: Experimental study was conducted to investigate the influence of rotation number ( Rt=ωD/u ∞) on the film cooling performance over a convex surface. Measurements of film cooling effectiveness η ad and heat transfer coefficient h f were presented for single film hole. Thermochromic liquid crystal (TLC) was used to obtain the temperature distributions on the curved surface. The results show that ① an obviously deflection occurs under the rotating condition;② with the increase of rotation number, the film cooling effectiveness decrease while the heat transfer coefficient increase;③ a reattachment phenomenon can be observed in the rotating condition.
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Key words:
- film cooling /
- curved surface /
- rotating /
- experiment
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[1] 韩介勤,桑地普.杜达,斯瑞纳斯.艾卡德著.燃气轮机传热和冷却技术[M].程代京,谢永慧译.西安:西安交通大学出版社,2005:87-171 Han J C, Dutta S, Ekkad S V. Gas turbine heat transfer and cooling technology [M]. Translated by Cheng Daijing, Xie Yonghui. Xi-an: Xi-an Jiaotong University Press, 2005: 87-171 (in Chinese) [2] Lutum E, Wolfersdorf J V, Semmler K, et al. An experimental investigation of film cooling on a convex surface subjected to favorable pressure gradient flow [J]. International Journal of Heat and Mass Transfer, 2001, 44: 939-951 [3] Lin Y L, Shih T I-P. Film cooling over flat, convex, and concave surfaces . AIAA-99-0344, 1999 [4] Kohli A, Bogard D G. Adiabatic effectiveness, thermal fields, and velocity fields for film cooling with large angle injections [J]. ASME Journal of Turbomachinery, 1997, 119: 352-358 [5] 陶智,杨晓军,丁水汀,等.旋转状态下曲率对气膜与主流掺混区域的影响[J].北京航空航天大学学报,2007, 33(2):132-135 Tao Zhi, Yang Xiaojun, Ding Shuiting, et al. Curvature effects on the film cooling with the rotation [J]. Journal of Beijing University of Aeronautics and Astronautics, 2007, 33(2): 132-135(in Chinese) [6] Tao Z, Yang X J, Ding S T, et al. Experimental study of rotation effect on film cooling over the flat wall with a single hole [J]. Experimental Thermal and Fluid Science, 2008, 32:1081-1089 -
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