Experimental observation on flow pattern of thermal convection in eccentric annular deep-liquid pools

IF 3.3 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science Pub Date : 2026-05-01 Epub Date: 2026-03-04 DOI:10.1016/j.expthermflusci.2026.111720

Chao Li , Dong-Ming Mo , Chun-Mei Wu , You-Rong Li

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Abstract

To clarify how eccentricity affects flow stability and the evolutionary process of thermal convection patterns, we conducted a sequence of experiments in deep-liquid pools with an eccentric annular structure. It is found that the bud-shaped flow pattern or straight spoke pattern will appear after the flow destabilization. In contrast to the flow structures appeared in concentric annular liquid pools, these patterns exhibit non-uniform distribution along the circumferential direction, that is, the spacing between adjacent flow modes is not uniform. Specifically, when the working fluid Prandtl (Pr) number is 6.7 and the liquid depth is fixed at 6 mm, the spoke-like patterns in the wide-slit area of the liquid pool will convert into bud-shaped structures with the increasing radial temperature difference, whereas they in the narrow-slit area start to oscillate. At Pr = 16.2 and 25.1, clear radial straight stripes are observed near the inner wall, and these radial straight stripes alternate with the straight spokes. The eccentricity also significantly reduces the critical value for flow destabilization. Notably, although buoyancy is increased in liquid layer depth, the eccentricity weakens the influence of buoyancy on flow stability.

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偏心环形深液池热对流流态的实验观察

为了阐明偏心对流动稳定性和热对流模式演化过程的影响，我们在具有偏心环状结构的深液池中进行了一系列实验。流动失稳后会出现花蕾型流型或直辐型流型。与同心环形液池中出现的流动结构相比，这些流型沿周向分布不均匀，即相邻流型之间的间距不均匀。具体而言，当工质普朗特（Pr）数为6.7，液深固定为6 mm时，随着径向温差的增大，液池宽缝区域的辐状结构转变为花蕾状结构，而窄缝区域的辐状结构开始振荡。在Pr = 16.2和25.1时，在内壁附近观察到明显的径向直条纹，这些径向直条纹与直辐条交替存在。偏心距也显著降低了流动不稳定的临界值。值得注意的是，虽然浮力在液层深度上有所增加，但偏心率减弱了浮力对流动稳定性的影响。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Experimental Thermal and Fluid Science 工程技术-工程：机械

CiteScore

6.70

自引率

3.10%

发文量

159

审稿时长

34 days

期刊介绍： Experimental Thermal and Fluid Science provides a forum for research emphasizing experimental work that enhances fundamental understanding of heat transfer, thermodynamics, and fluid mechanics. In addition to the principal areas of research, the journal covers research results in related fields, including combined heat and mass transfer, flows with phase transition, micro- and nano-scale systems, multiphase flow, combustion, radiative transfer, porous media, cryogenics, turbulence, and novel experimental techniques.