Partitioning effect on natural convection in a circular enclosure with an asymmetrically placed inclined plate
Partitioning effect on natural convection in a circular enclosure with an asymmetrically placed inclined plate
复制标题
DOI：
10.1016/j.icheatmasstransfer.2017.10.015
复制
发表时间：
2018
影响因子：
7
通讯作者：
Wei Zhang;Yi-kun Wei;Xiao-ping Chen;H. Dou;Zuchao Zhu
中科院分区：
文献类型：
--
作者：
Wei Zhang;Yi-kun Wei;Xiao-ping Chen;H. Dou;Zuchao Zhu
本文对Ra = 106时具有平板的圆形封闭腔内的稳态层流自然对流进行了数值研究。板沿径向沿着倾斜放置，但关于外壳中心不对称，偏心率定义为两个实体中心之间的距离。外壳和板分别保持在低温和高温下。本研究的目的是探讨两个重要参数的影响，即，偏心率（r）和倾角（α）对固定板-平板系统流动和传热特性的影响。数值模拟是使用我们的内部四阶有限差分代码，这是很好地验证。通过对r/D= 0.00（0.05）~ 0.20和α= 0°（5°）~ 180°（D为腔体直径）时的总传热量、温度分布、各种旋涡的形成和演化以及局部传热量的分布，分析了这两个参数的影响。数值结果表明，近水平平板的分隔效应对自然对流有很大的抑制作用，而在低倾角和高倾角时，分隔效应对自然对流的抑制作用较小。根据偏心率和倾斜度的不同，封闭腔左右两侧最多可分别存在2个和3个旋涡，旋涡的形成、空间演化行为和强度变化呈现复杂的模式，并与换热特性密切相关。对于高偏心率的配置，在差距中的热传递可以由对流或传导取决于差距的大小，其中后者的特征在于预期的最大局部热传递率的周向位置的线性变化与倾斜。
This work presents a numerical investigation on steady-state laminar natural convection in a circular enclosure with an inner flat plate atRa= 106. The plate is inclined placed along the radial direction but is asymmetric about the center of enclosure, with eccentricity defined as the distance between the centers of two entities. The enclosure and plate are kept at low and high temperatures, respectively. The objective of this study is to explore the effects of two significant parameters, i.e., eccentricity (r) and inclination (α) of the plate, on the flow and heat transfer characteristics of the enclosure-plate system. The numerical simulation is performed using our in-house fourth-order finite difference code which is well validated. The effects of the two parameters are analyzed by the total heat transfer rate, temperature distribution, formation and evolution of various vortices, and distribution of local heat transfer rate forr/D= 0.00(0.05)0.20 andα= 0°(5°)180° whereDis the enclosure diameter. Numerical results reveal that natural convection is weakened by the partitioning effect of nearly horizontal plate since fluid circulation is greatly constrained, while the effect is minor at low and high inclinations where fluid circulation is pronounced. Depending on the eccentricity and inclination, there could be at most two and three vortices in the left and right halves of the enclosure, respectively, whose formation and spatial evolution behaviors and intensity variations exhibit complex patterns, and are closely related with the heat transfer characteristics. For high eccentricity configurations, the heat transfer in the gap can be dominated by either convection or conduction depending on the gap size, the latter of which is characterized by the expected linear variation of circumferential position of maximum local heat transfer rate with the inclination.