Numerical simulations of heat transfer distribution of a two-pass square channel with V-rib turbulator and bleed holes
Numerical simulations of heat transfer distribution of a two-pass square channel with V-rib turbulator and bleed holes
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DOI：
10.1007/s00231-013-1156-5
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发表时间：
2013-04
影响因子：
2.2
通讯作者：
Sourabh Kumar;R. Amano;J. M. Lucci
中科院分区：
文献类型：
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作者：
Sourabh Kumar;R. Amano;J. M. Lucci
燃气轮机叶尖区域由于存在温差而面临高热负荷，因此必须努力实现高耐久性和安全运行。需要改进和强大的冷却方法来降低涡轮叶片的传热速率。由于叶尖外泄漏，暴露于高气流的叶尖区域承受高局部热负荷。射流冲击、销钉冷却等技术用于冷却叶片。更常用的方法是使用180度转弯的蛇形通道。本文对带有肋形湍流器和排气孔的两道方形通道的换热分布进行了数值模拟。在通道中采用了周期性肋形紊流器和排气孔。肋排形式为60°V肋、60°倒V肋、进口段60°V肋与出口段60°倒V肋组合、进口段倒V肋与出口段V肋组合。使用Fluent对结果进行数值计算，雷诺数分别为12,500和28,500。用于计算的湍流模型为k-ω-SST和RSM。采用基于温度和基于剪切应力的技术进行换热分布预测。对60度V型肋、60度倒V型肋的实验结果进行了比较，对所得结果进行了验证。详细分布表明，在排气孔和肋形湍流器周围有明显的换热峰。比较了肋形湍流器不同方向模型的总体性能。研究发现，进口60°倒V肋和出口60°倒V肋带排气孔的组合可以提供更好的热处理效果。建议采用带排气孔的肋形紊流器来增强叶片冷却，以达到热学和力学设计要求之间的最佳平衡。
The blade tip region in gas turbine encounters high thermal loads due to temperature difference and hence efforts for high durability and safe operations are essential. Improved and robust methods of cooling are required to downgrade heat transfer rate to turbine blades. The blade tip regions, which are exposed to high gas flow, suffers high local thermal load which are due to external tip leakage. Jet impingement, pin cooling etc. are techniques used for cooling blades. A more usual way is to use serpentine passage with 180-degree turn. In this study, numerical simulation of heat transfer distribution of a two-pass square channel with rib turbulators and bleed holes were done. Periodical rib turbulators and bleed holes were used in the channel. The ribs arrangement were 60 degree V rib, 60 degree inverted V ribs, combination of 60 degree V rib at inlet and 60 inverted V rib at outlet section and combination of Inverted V at inlet and V rib at the outlet. The results were numerically computed using Fluent with Reynolds number of 12,500 and 28,500. Turbulence models used for computations were k-ω-SST and RSM. Temperature based and shear stress based techniques were used for heat transfer distribution prediction. The results for 60 degree V rib, 60 degree inverted V ribs were compared with the experimental results for validation of the results obtained. Detailed distribution shows distinctive peaks in heat transfer around bleed holes and rib turbulator. Comparisons of the overall performance of the models with different orientation of rib turbulator are presented. It is found that due to the combination of 60 degree inverted V rib in inlet and 60 V rib in outlet with bleed holes provides better heat treatment. It is suggested that the use of rib turbulator with bleed holes provides suitable for augmenting blade cooling to achieve an optimal balance between thermal and mechanical design requirements.