Investigation on film cooling performance from a row of round-to-slot holes on flat plate
Investigation on film cooling performance from a row of round-to-slot holes on flat plate
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DOI：
10.1016/j.ijthermalsci.2017.04.029
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发表时间：
2017-08
影响因子：
4.5
通讯作者：
Jing-zhou Zhang;Xing-dan Zhu;Ying Huang;Chunhua Wang
中科院分区：
文献类型：
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作者：
Jing-zhou Zhang;Xing-dan Zhu;Ying Huang;Chunhua Wang
进行了一系列数值计算来研究平面上一排圆孔到槽孔的薄膜冷却。特别关注了在典型吹气比范围为1.0至2.0的情况下，槽宽度（0.2≤s/d≤0.5）对固定槽长l/d=2.0的圆槽孔气膜冷却性能的影响。此外，还进行了多项实验测试，以获得特定几何形状的圆槽孔的气膜冷却效果和流量系数。结果表明，圆槽孔内部由于膜孔过渡流道的作用，冷却液流向两侧流动占主导地位。由于从圆孔到槽孔喷出的冷却剂射流与一次流之间的特定相互作用机制，热一次流主要从膜孔中心线夹带到冷却剂层中。总体而言，扩散圆槽孔在增强膜孔附近的膜冷却方面显示出其有利的特征。然而，超过一定距离后，会聚圆形槽孔比扩散圆形槽孔获得稍高的横向平均薄膜冷却效果。 s/d= 0.2 的会聚圆形槽孔比圆柱形孔产生更高的横向平均传热系数。当超过 x/d= 10 时，扩散圆形槽孔产生的横向平均对流传热系数低于圆柱形孔。随着槽宽度减小，流量系数显着降低。
A series of numerical computations are conducted to investigate the film cooling from a row of round-to-slot holes on a flat surface. Particular attention is paid to explore effect of slot width (0.2 ≤ s/d ≤ 0.5) on the film cooling performances of round-to-slot holes with a fixed slot length ofl/d= 2.0 under typical blowing ratios ranged from 1.0 to 2.0. Besides, several experimental tests are also performed to obtain the film cooling effectiveness and discharge coefficient of the round-to-slot holes with specific geometries. The results show that the coolant flow turning towards both lateral sides due to the transitional flow passage of film-hole is dominated inside the round-to-slot hole. Owing to the specific interaction mechanism between the coolant jet issued from round-to-slot holes and the primary flow, the hot primary flow is mainly entrained into the coolant layer from the film-hole centerline. In general, the diffusing round-to-slot hole shows its favorable feature on the film cooling enhancement near the film hole. However, beyond a certain distance, the converging round-to-slot hole achieves a little higher laterally-averaged film cooling effectiveness than the diffusing round-to-slot hole. The converging round-to-slot hole withs/d= 0.2 produces higher laterally-averaged heat transfer coefficient than the cylindrical hole. While the diffusing round-to-slot hole produces less laterally-averaged convective heat transfer coefficient than the cylindrical hole beyondx/d= 10. The discharge coefficient decreases significantly as the slot width reduces.