Enhancing the flow and heat transfer in a convective cavity using symmetrical and adiabatic twin fins
Enhancing the flow and heat transfer in a convective cavity using symmetrical and adiabatic twin fins
复制标题
使用对称和绝热双翅片增强对流腔中的流动和传热
DOI：
10.1016/j.ijheatmasstransfer.2019.118447
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发表时间：
2019-10-01
影响因子：
5.2
通讯作者：
Zhao, Yongling
中科院分区：
文献类型：
--
作者：
Liu, Yang;Zhang, Shuaikun;Zhao, Yongling
在本研究中，在不同瑞利数和不同翅片位置的情况下，对每个侧壁附有两个水平绝热翅片的差热腔中自然对流的增强和相关传热进行了数值研究。该数值方法通过代表性尺度和实验阴影图结果进行了验证。在早期和完全发展阶段都确定了典型的双羽流流态。本文详细研究了两个羽流的相互作用。随着瑞利数的增加，两个翅片上方羽流的分离频率增加。研究还表明，准稳态阶段上游羽流的分离频率不仅取决于上游流的特性，而且很大程度上取决于下游翅片的位置。当下游翅片向空腔顶部移动时，频率发生非单调变化，表明复杂的非线性特性。与没有翅片的情况相比，流经腔体的流速显着提高，早期提高了136.2%，完全发展阶段提高了124.8%。在瑞利数为 3.68 x 10(9) 时，侧壁上具有对称翅片的空腔的传热率提高了 12.7%。 (C) 2019 Elsevier Ltd. 保留所有权利。
The enhancement of natural convection flow and the associated heat transfer in a differentially heated cavity with two horizontal adiabatic fins attached to each sidewall are numerically investigated at different Rayleigh numbers and with various fin positions in this study. The numerical approach is validated by both representative scales and experimental shadowgraph results. A typical double-plume flow regime is identified at both the early and fully-developed stages. The interaction of the two plumes is investigated in detail in this paper. With the increasing of the Rayleigh number, the separation frequency of the plume above both fins increases. It is also revealed that the separation frequency of the upstream plume at the quasi-steady stage does not only depend on the characteristics of the upstream flow, but also greatly depends on the position of the downstream fin. The frequency varies non-monotonically as the down-stream fin moving toward the cavity ceiling, suggesting complex nonlinear characteristics. Compared to the scenario without any fin, the flow rate across the cavity is significantly boosted, which is increased by up to 136.2% at the early stage and 124.8% at the fully-developed stage. The heat transfer rate across the cavity having symmetrical fins on sidewalls is enhanced by up to 12.7% at a Rayleigh number of 3.68 x 10(9). (C) 2019 Elsevier Ltd. All rights reserved.