Flowfield Measurements for Film-Cooling Holes With Expanded Exits
Flowfield Measurements for Film-Cooling Holes With Expanded Exits
复制标题
DOI：
10.1115/1.2841410
复制
发表时间：
1996-06
影响因子：
1.7
通讯作者：
K. Thole;M. Gritsch;A. Schulz;S. Wittig
中科院分区：
文献类型：
--
作者：
K. Thole;M. Gritsch;A. Schulz;S. Wittig
改进用于燃气涡轮机叶片的冷却方法的一个可行选择是优化膜冷却孔的几何形状。为了优化几何形状，需要了解孔几何形状对复杂的射流-横流相互作用的影响。本文介绍了详细的流场测量三种不同的单一，按比例放大的孔的几何形状，所有在一个单位的吹风比和密度比的比较。孔的几何形状包括圆孔、具有横向扩展出口的孔和具有向前-横向扩展出口的孔。除了文献中唯一的扩大冷却孔几何形状的流场测量外，用于这些测量的试验设备也是唯一的，因为外部主流马赫数（Ma{sub {infinity}} = 0.25）和内部冷却剂供给马赫数（Ma{sub {c} = 0.3）几乎是匹配的。结果表明，通过扩大冷却孔的出口，冷却射流的穿透和强剪切区都显着减少相对于一个圆孔。尽管所有三种孔几何形状的峰值湍流水平名义上相同，但湍流源不同。由于扩张角过大，两个扩张孔的峰值湍流水平更多地位于冷却孔的出口处。圆孔的湍流度峰值位于出口下游，出口处的速度梯度非常大。«少
One viable option to improve cooling methods used for gas turbine blades is to optimize the geometry of the film-cooling hole. To optimize that geometry, effects of the hole geometry on the complex jet-in-crossflow interaction need to be understood. This paper presents a comparison of detailed flowfield measurements for three different single, scaled-up hole geometries, all at a blowing ratio and density ratio of unity. The hole geometries include a round hole, a hole with a laterally expanded exit, and a hole with a forward-laterally expanded exit. In addition to the flowfield measurements for expanded cooling hole geometries being unique to the literature, the testing facility used for these measurements was also unique in that both the external mainstream Mach number (Ma{sub {infinity}} = 0.25) and internal coolant supply Mach number (Ma{sub c} = 0.3) were nearly matched. Results show that by expanding the exit of the cooling holes, both the penetration of the cooling jet and the intense shear regions are significantly reduced relative to a round hole. Although the peak turbulence level for all three hole geometries was nominally the same, the source of that turbulence was different. The peak turbulence level for both expanded holes was locatedmore » at the exit of the cooling hole resulting from the expansion angle being too large. The peak turbulence level for the round hole was located downstream of the hole exit where the velocity gradients were very large.« less