摘要
为了研究扇形孔不同复合扩张角对平板气膜冷却的影响,分别对10°、12°、14°、16°4种复合扩张角的气膜孔的流动和传热特性进行了数值模拟。研究结果表明,4种气膜孔复合扩张角孔型出口下游均出现从中心向上抬升的反向旋转涡对,将主流燃气卷吸进来;较大的复合扩张角孔型使得气膜出流在侧向覆盖相对更宽,可以有效地降低壁面温度;在相同吹风比下(M=0.75~1.75),12°复合扩张角孔型在气膜出流方向(40D范围区域)的平均绝热冷却效率明显要高于其他3种孔;吹风比M=1时,冷气出流复合扩张角增大的同时,冷却效率η≥0.3的覆盖面从X/D≈40减小到X/D≈8。同时,针对侧向扩张12°的7种不同后倾角的扇形孔进行了研究,发现其后倾角(范围10°~14°)的变化对冷却效率有一定的增强作用。研究成果可为燃气轮机透平叶片表面气膜孔的设计及升级改进提供参考。
The flow and heat transfer characteristics of four compound-expansion angles of 10°,12°,14°,16°are numerically simulated to study the effects of different compound-expanding angles of fan-shaped holes on film cooling of flat plates.The results show that there are reverse rotating vortices rising from the center to the downstream of the fan-shaped holes under four compound angles,which suck in the mainstream gas;the fan-shaped hole with larger compound angle makes the film outflow cover wider in the spreading direction,which can effectively reduce the wall temperature;at the same blowing ratio(M=0.75-1.75),the average adiabatic cooling efficiency of fan-shaped hole under 12°compound-expanding angle in the direction of film outflow(40 D range)is obviously higher than that of the other three holes;at blowing ratio M=1,the coverage of cooling efficiency(η≥0.3)decreases from X/D≈40 to X/D≈8 while the compound angle increases.Meanwhile,seven kinds of backward inclined holes with 12°expansion are studied,the increase of the backward inclined angle(10°~14°)has a positive effect at the enlargement of the cooling efficiency.The research results can provide reference for the design and upgrading of the film cooling holes on the surface of gas turbine blades and vanes.
作者
赵锦杰
何磊
赵连会
黄启鹤
ZHAO Jinjie;HE Lei;ZHAO Lianhui;HUANG Qihe(Shanghai Electric Gas Turbine Co.,Ltd.,Shanghai 200240,China)
出处
《热力透平》
2020年第1期69-74,共6页
Thermal Turbine
关键词
气膜冷却
数值模拟
扇形孔
film cooling
numerical simulation
fan-shaped hole
