Heat transfer and flow structure in centrally-confined 2-D Rayleigh-Bénard convection

IF 2.5 3区 工程技术
Cong Sun, Jian-zhao Wu, Xiao-hui Meng, Cai-xi Liu, Wei Xu, Yu-hong Dong, Quan Zhou
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引用次数: 0

Abstract

Through direct numerical simulations, we investigated the flow structure and heat transfer of the centrally confined 2-D Rayleigh-Bénard (RB) convection over the Rayleigh number range 9 × 105Ra ≤ 109 at a fixed Prandtl number Pr = 4.3. It is found that with increasing Ra, the number of convection rolls in the central vertical channel increases from zero to three. When there is no rolls in the vertical channel, the convective flow in central region is significantly influenced by the boundary layer, whereas when the convection rolls is generated in the vertical channel, the convective flows in central regions is free from the boundary layer limitation, and by defining the characteristic length, one obtains the heat transfer scaling law relation in vertical channel, i.e., NuvcRa 0.476±0.005vc , which could be the evidence of “ultimate regime”.

集中封闭的二维瑞利-贝纳德对流中的传热和流动结构
通过直接数值模拟,我们研究了在固定普朗特数 Pr = 4.3 条件下,雷利数范围 9 × 105 ≤ Ra ≤ 109 的中心约束二维雷利-贝纳德(RB)对流的流动结构和传热。研究发现,随着 Ra 的增加,中央垂直通道中的对流辊数从零增加到三个。当垂直通道中没有对流辊时,中心区域的对流受边界层的影响很大,而当垂直通道中产生对流辊时,中心区域的对流不受边界层的限制,通过定义特征长度,可以得到垂直通道中的传热比例关系,即 Nuvc ∼ Ra 0.476±0.005vc ,这可能是 "终极制度 "的证据。
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来源期刊
自引率
12.00%
发文量
2374
审稿时长
4.6 months
期刊介绍: Journal of Hydrodynamics is devoted to the publication of original theoretical, computational and experimental contributions to the all aspects of hydrodynamics. It covers advances in the naval architecture and ocean engineering, marine and ocean engineering, environmental engineering, water conservancy and hydropower engineering, energy exploration, chemical engineering, biological and biomedical engineering etc.
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