Large Eddy Simulation of Flow and Heat Transfer in an Internal Cooling Duct With High Blockage Ratio 45° Staggered Ribs
Large Eddy Simulation of Flow and Heat Transfer in an Internal Cooling Duct With High Blockage Ratio 45° Staggered Ribs
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DOI：
10.1115/gt2005-68086
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
A. Viswanathan;D. Tafti;S. Abdel-Wahab
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文献类型：
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作者：
A. Viswanathan;D. Tafti;S. Abdel-Wahab
本文给出了与主流方向成45°角的方肋固定管道单位周期内流体动力和热发展湍流的数值预报。肋高度对通道水力直径（e/Dh）为0.375，肋间距对肋高度（P/e）为10。所考虑的区域是纵横比为1：2.5的矩形通道，在顶壁和底壁上以交错方式布置有45°肋。这些计算是针对27，000的整体Re进行的。肋的几何形状沿肋沿着引入强的二次流。在肋后面形成一个大的螺旋涡流，在到达外壁之前就破裂了。与外壁相比，这导致内壁处的热传递更高，这与在具有低阻塞肋的方形通道中观察到的趋势相反。在具有低阻塞肋的方形管道中，二次流具有两个反向旋转的单元，其不改变通过通道的方向。然而，在这种情况下，仅观察到一个旋转细胞，其在经过连续的肋时改变方向。平均摩擦和传热增强比与实验结果[1]一致，预测值在测量值的15%以内。© 2005 ASME
Numerical predictions of a hydrodynamic and thermally developed turbulent flow are presented for a unit period of a stationary duct with square ribs aligned at 45° to the main flow direction. The rib height to channel hydraulic diameter (e/Dh ) is 0.375 and the rib pitch to rib height (P/e) is 10. The domain under consideration is a rectangular passage of aspect ratio 1:2.5 with 45° ribs on the top and bottom walls arranged in a staggered fashion. The computations are carried out for a bulk Re of 27,000. The rib geometry introduces a strong secondary flow along the rib. A large helical vortex develops behind the rib which breaks down before it reaches the outer wall. This results in higher heat transfer at the inner wall as compared to the outer wall, which is in contrast to the trend observed in a square channel with low blockage ribs. In a square duct with low blockage ribs the secondary flow has two counter-rotating cells which do not change direction through the channel. However in this case only one rotating cell is observed in this case, which changes direction as it passes over successive ribs. The average friction and the heat transfer augmentation ratios are consistent with the experimental results [1], predicting values within 15% of the measured quantities.© 2005 ASME