涡轮导叶W型孔全气膜冷却效率实验研究

Experimental Study of Full Coverage Film Cooling Effectiveness of Turbine Guide Vane with W-Shaped Holes

关键词:  涡轮导叶  主流湍流度  流量比  气膜冷却效率  液晶

Key words:  Turbine guide vane  Mainstream turbulence intensity  Flow rate ratio  Film cooling effectiveness  Liquid crystal

摘要:

为了研究涡轮导叶W型孔全气膜冷却效率的分布规律，使用热色液晶测量了在流量比为5.5%，8.4%和12.5%，主流湍流度为1%，9%和15%下W型孔全气膜涡轮导叶的气膜冷却效率，并与相同工况下的圆柱型孔全气膜叶片的冷却效率结果进行了对比。结果表明：在低湍流度下，流量比变化对W型孔叶片不同区域冷却效率的影响规律不同；而在高湍流度下，流量比增大使W型孔叶片的冷却效率整体升高；在研究的所有流量比下，W型孔叶片的冷却效率均随着湍流度的升高而降低；与圆柱型孔叶片相比，在中低湍流度下，W型孔的冷气壁面贴附性和展向覆盖效果更好，W型孔叶片的冷却效率具有明显优势，然而在高湍流度下由于W型孔的冷气速度低且分布分散，易在高湍流度影响下耗散，W型孔叶片的冷却效率优势较小，甚至在高湍流度大流量比下，圆柱型孔叶片的面平均冷却效率比W型孔叶片高15%左右。

Abstract:

In order to study the full coverage film cooling effectiveness of the turbine guide vane with W-shaped holes， the film cooling effectiveness of a three-dimensional turbine guide vane with W-shaped holes was measured using transient liquid crystal technique. The flow rate ratios are 5.5%， 8.4% and 12.5%， and the mainstream turbulence intensities are 1%， 9% and 15%. In addition， the results were compared with those of the cylindrical hole full coverage film cooling vane under the same conditions. The results show that at low turbulence intensity condition， the effects of the flow rate ratio on the film cooling effectiveness are different in different regions of the W-shaped hole vane. At high turbulence intensity condition， the increase of flow rate ratio generally increases the film cooling effectiveness of the W-shaped hole vane. At all the mass flow rate ratio conditions studied in this paper， the film cooling effectiveness of the W-shaped hole vane decreases with increasing the turbulence intensity. Compared with the cylindrical hole vane， at low and middle turbulence intensities， the coolant from the W-shaped holes has a better attachment and spanwise coverage to the vane surface， which makes the W-shaped hole vane have more advantage in film cooling effectiveness. However， at high turbulence intensity condition， the coolant from the W-shaped hole is more dispersive and has lower speed， so the coolant is easy to dissipate dramatically， which reduces the advantage of W-shaped hole vane. Even more， the area-averaged film cooling effectiveness of the cylindrical hole vane is about 15 % higher than that of the W-shaped hole vane at high turbulence intensity and high flow rate ratio condition.