Numerical study of non-isothermal flow with convective heat transfer in a curved rectangular duct
Numerical study of non-isothermal flow with convective heat transfer in a curved rectangular duct
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DOI：
10.1016/j.ijthermalsci.2005.03.013
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发表时间：
2005-11
影响因子：
4.5
通讯作者：
S. Yanase;R. Mondal;Y. Kaga
中科院分区：
文献类型：
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作者：
S. Yanase;R. Mondal;Y. Kaga
采用谱法对通过纵横比为 2 的弯曲矩形管道进行对流换热的非等温流进行数值研究，其中垂直外（加热）侧壁和内（冷却）侧壁之间存在温差。对 Grashof 数 100<Gr⩽1000 和 Dean 数 0⩽Dn⩽1000 进行数值计算。本文详细讨论了Gr=500和Gr=1000的两种情况。在对参数范围进行全面调查后，对于这两种情况，使用牛顿-拉夫森迭代法找到了五个稳定解的分支。然后研究每个分支的线性稳定性特性。发现在获得的多个稳定解中，当Gr=500时，只有一个稳定解对于Dean数的单一范围是线性稳定的，而当Gr=1000时，另一方面，同一分支上的三个不同的Dean数区间都存在线性稳定区域。努塞尔数计算为差热垂直侧壁的水平传热指数。研究发现，由于离心力的增强，二次流产生的对流显着增加了从受热壁到流体的传热，因此流动变得周期性，然后变得混乱，随着迪恩数的增加，传热速率相对于直通道显着增加。
Non-isothermal flow with convective heat transfer through a curved rectangular duct of aspect ratio 2 is numerically studied by use of the spectral method with a temperature difference between the vertical outer (heated) and inner (cooled) sidewalls. Numerical calculations are carried out for the Grashof numbers 100<Gr⩽1000 over the Dean number 0⩽Dn⩽1000. In the present paper, two cases of the Grashof numbers Gr=500 and Gr=1000 are discussed in detail. After a comprehensive survey over the parametric ranges, five branches of steady solutions are found using the Newton–Raphson iteration method for both the cases. Linear stability characteristics of each branch are then studied. It is found that among multiple steady solutions obtained, only one steady solution is linearly stable for a single range of the Dean number for Gr=500, for Gr=1000, on the other hand, linear stability region exists in three different intervals of the Dean number on the same branch. Nusselt numbers are calculated as an index of the horizontal heat transfer for differentially heated vertical sidewalls. It is found that the convection due to the secondary flow, enhanced by the centrifugal force, increases heat transfer significantly from the heated wall to the fluid, and whence the flow becomes periodic and then chaotic, as the Dean number increases, the rate of heat transfer increases remarkably with respect to a straight channel.