Experiments of combined heat transfer in leading of blades at rotating state
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摘要: 通过液晶示温瞬态实验方法,对旋转状态下涡轮叶片前缘带气膜出流的冲击冷却结构的换热特性进行了研究,获得了哥氏力、离心力对复合换热效果的影响.实验参数:射流进口雷诺数Re=4 000,旋转数Ro=0~0.139.实验结果表明:随着旋转数的升高,实验模型的整体换热效果逐渐减弱,在旋转数为0.139时,与静止状态相比冲击面平均努塞尔数Nu下降了33%,压力面和吸力面分别下降了20.5%和7.5%;哥氏力的作用加速了射流的扩散,是造成旋转换热减弱的主要原因;哥氏力和离心力的共同影响使得吸力面的换热好于压力面;气膜孔的存在改变了流动结构,极大的增强了孔周边区域的换热效果.Abstract: Transient experiment was performed to study the heat transfer characteristic of impingement cooling with outflow film in the leading of turbine blades at rotating state. And, the effect of Coriolis forces and centrifugal forces on combined heat transfer effectiveness was discussed. The Reynolds number based on the inlet velocity of the impinging jet and hole diameter is 4 000. The Rotation number is from 0 to 0.139. Experiments' results show that the heat transfer effectiveness decreases with the Rotation number increasing. The average Nusselt number on the impingement face decreases 33%, and the average Nusselt number on the pressure face and the suction face decreases 20.5% and 7.5%, respectively. The effect of Coriolis forces enhance the spreading rate of the jet flow, which is mostly factor that result in heat transfer characteristic down. The effect of Coriolis forces together with centrifugal forces arouses the difference of heat transfer on pressure face and suction face at rotating state, and the average Nusselt number on the suction surface was larger than that on the pressure surface. The presence of the film holes changes the flow structure and gathers head the heat transfer effectiveness of films'border area.
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Key words:
- impinging /
- film /
- heat transfer /
- transient experiment
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[1] General Motors Corporation.Laminated porous metal:USA,US3584972 .1971-06-15 [2] General Motors Corporation.Turbine blade:USA,US3619082 .1971-11-09 [3] General Motors Corporation.Cooled airfoil:USA,US3732031 .1973-05-08 [4] General Motors Corporation.Turbine cooling:USA,US3963368 .1976-06-15 [5] Rolls-Royce Limited.Cooling of aerofoil shaped blades:USA,US3620643 .1971-11-16 [6] Bunker R S,Metzger D E.Local heat transfer in internally cooled turbine airfoil leading edge regions:partⅠ-impingement cooling without film coolant extraction [J].Journal of Turbomachinery,1990,112:451-458 [7] Bunker R S,Metzger D E.Local heat transfer in internally cooled turbine airfoil leading edge regions: partⅡ-impingement cooling with film coolant extraction [J].Journal of Turbomachinery,1990,112:459-466 [8] Taslim M E,Pan Y.An experimental study of impingement on roughened airfoil leading edge walls with film holes[J].ASME Journal,2001,123:767-773 [9] Taslim M E,Bakhtari K,Liu H.Experimental and numerical investigations of impingement on a rib-roughened leading edge wall [J].ASME Journal,2003,125:682-691 [10] Hong S K,Lee D H,Cho H H.Effect of jet direction on heat/mass transfer of rotating impingement jet [J].Applied Thermal Engineering,2009,29(14-15):2914-2920 [11] 吴宏,陶智,徐国强.带气膜出流的旋转叶片冲击冷却的实验研究[J].航空动力学报,2000,15(4):375-380 Wu Hong,Tao Zhi,Xu Guoqiang.Experiments of impinging cooling in leading edges of rotating blades with outflow film [J].Journal of Aerospace Power,2000,15(4):375-380 (in Chinese) [12] 王开,徐国强,孙纪宁,等.冲击与气膜的组合形式对冷却效果的影响[J].北京航空航天大学学报,2008,34(7):751-754 Wang Kai,Xu Guoqiang,Sun Jining,et al.Effect of combined impingement cooling and film cooling onhybrid cooling effectiveness [J].Journal of Beijing University of Aeronautics and Astronautics,2008,34(7):751-754(in Chinese) [13] 王开,徐国强,陶智,等.进气方式对冲击与气膜组合冷却效果的影响[J].工程热物理学报,2008,29(7):1185-1188 Wang Kai,Xu Guoqiang,Tao Zhi,et al.Effect of plenum feed configurations on the cooling effectiveness in the hybrid cooling configuration [J].Journal of Engineering Thermophysics,2008,29(7): 1185-1188(in Chinese)
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