Abstract High pressure turbine vane surface and endwall regions are extensively cooled through discrete holes and leakage flow from combustor-turbine interface gap. For making better use of the limited amount of the leakage flow, this paper describes numerical investigation of endwall film cooling performance of a two-dimensional cascade with upstream interrupted slot injection. The geometry of the vane, size of the slot and mainstream parameters are all taken from a real engine high pressure turbine. The effects of varying blowing ratio, location of the upstream slot and coolant incidence angle on cooling effectiveness are studied. The ranges of the studied parameters are: blowing ratio 1.0, 1.7, 1.86; slot location Z/Cax = −0.1, −0.2, −0.3; coolant incidence angle −10°, 10°, 20°. The calculations are completed by solving three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with shear stress transport (SST) k-ω turbulence model, meanwhile, the turbulence model was validated by comparing the calculated results with the experiment data. The calculated results show an important influence of blowing ratio and axial position of the interrupted slot on film cooling effectiveness. Cooling Effectiveness is increased with increasing blowing ratio and decreasing distance between the slot and leading edge of the vane. To compare with BR = 1.7 cooling effectiveness can be improved significantly in the condition of BR = 1.86. Slot location of Z/Cax = −0.1 provides much higher cooling effectiveness than the rest two locations. The physical mechanism of the improvement is that in the condition of high blowing ratio high momentum coolant flow helps to reduce the strength of horseshoe vortex and therefore to limit its negative effect on the cooling effectiveness. The high momentum coolant jet impinges on leading edge of the vane and climbs the surface of it. The coverage of the coolant at the leading edge endwall and pressure side endwall junction becomes better. The contours of effectiveness for different slot location are similar to those of different blowing ratio. The momentum of the coolant jet increases with the slot moving close to the leading edge of the vane and creates similar effectiveness contour patterns of raising blowing ratio. The effect of varying coolant incidence angle on the cooling effectiveness is weaker than blowing ratio and slot location. Average cooling effectiveness is increased about 14% when the angle changed from 10° to 20°.

中文翻译：

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从上游间断槽注入冷却剂的涡轮端壁薄膜冷却和二次流的计算研究

摘要 高压涡轮叶片表面和端壁区域通过离散孔和燃烧室-涡轮界面间隙的泄漏流得到广泛冷却。为了更好地利用有限量的泄漏流，本文描述了具有上游间断缝隙注入的二维叶栅端壁薄膜冷却性能的数值研究。叶片几何形状、槽缝尺寸和主流参数均取自真实发动机高压涡轮。研究了不同的吹气比、上游槽的位置和冷却剂入射角对冷却效率的影响。研究参数范围为：吹塑比1.0、1.7、1.86；插槽位置 Z/Cax = -0.1, -0.2, -0.3; 冷却剂入射角 -10°、10°、20°。计算是通过使用剪切应力传递 (SST) k-ω 湍流模型求解三维雷诺-平均纳维-斯托克斯 (RANS) 方程来完成的，同时，通过将计算结果与实验数据进行比较来验证湍流模型。计算结果表明，吹气比和间断槽的轴向位置对薄膜冷却效果有重要影响。冷却效率随着鼓风比的增加以及槽与叶片前缘之间距离的减小而增加。与BR = 1.7相比，在BR = 1.86的条件下，冷却效果可以显着提高。Z/Cax = -0.1 的插槽位置比其余两个位置提供更高的冷却效率。改进的物理机制是在高吹比条件下，高动量冷却剂流有助于降低马蹄形涡流的强度，从而限制其对冷却效果的负面影响。高动量冷却剂射流撞击叶片的前缘并爬上它的表面。冷却剂在前缘端壁和压力侧端壁连接处的覆盖变得更好。不同槽位的效率曲线与不同吹气比的曲线相似。冷却剂射流的动量随着槽缝靠近叶片前缘移动而增加，并产生类似的提高吹气比的效率轮廓模式。改变冷却剂入射角对冷却效率的影响弱于吹气比和槽位置。