Spiral-channel holes are utilized on the turbine endwall to enhance cooling effectiveness. Numerical simulations and experimental verification are conducted to analyze the cooling performance and energy loss of spiral-channel holes, as well as the influence of parameters and flow field structure on the vane. Results reveal that the energy loss due to the spiral-channel hole is slightly higher than that of the cylindrical hole at low blowing ratio (M), with the opposite being true for M exceeds 1.5. Increasing M heightens the film effectiveness around the hole but reduces coolant coverage downstream of the hole. The cooling capacity of the spiral-channel hole outperforms cylindrical hole around the hole, resulting in more uniform transverse film effectiveness and greatly improved the cooling effect on the pressure section, particularly at high M. The introduction of compound angle further enhances the cooling performance of spiral-channel hole, but increases the energy loss. Upstream the hole, the laterally-averaged film effectiveness of spiral-channel hole with −28° compound angle is 16.9 % higher than that of cylindrical hole, and 20.1 % higher downstream the hole. The spiral-channel hole with −28° compound angle exhibits the best cooling performance on the pressure side, while the spiral-channel hole with 48° compound angle provides optimal cooling effect on the suction side. Moreover, the pressure section exhibits a larger vortex scale and intensity compared to the suction section. The hole with positive and negative compound angle exhibits minimal difference in the flow field structure between the pressure and suction sections, and form better protection on the endwall with a smaller zero coverage zone.

中文翻译：

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螺旋通道孔端壁气膜冷却效果及能量损失


涡轮端壁上采用螺旋通道孔以增强冷却效果。通过数值模拟和实验验证，分析了螺旋通道孔的冷却性能和能量损失，以及参数和流场结构对叶片的影响。结果表明，在低吹胀比（M）时，螺旋通道孔引起的能量损失略高于圆柱形孔，当M超过1.5时，情况相反。增加 M 会提高孔周围的油膜有效性，但会减少孔下游的冷却剂覆盖范围。螺旋通道孔的冷却能力优于孔周围的圆柱孔，横向油膜效果更加均匀，大大提高了压力段的冷却效果，特别是在高M处。复合角的引入进一步增强了通道的冷却性能。螺旋通道孔，但增加了能量损失。在孔上游，-28°复合角螺旋通道孔的横向平均膜效率比圆柱形孔高16.9%，在孔下游高20.1%。 -28°复合角的螺旋通道孔在压力侧具有最佳的冷却性能，而48°复合角的螺旋通道孔在吸力侧具有最佳的冷却效果。此外，与吸入部分相比，压力部分表现出更大的涡流规模和强度。正负复合角的孔，压力段和吸力段的流场结构差异最小，对端壁形成更好的保护，零覆盖区更小。