两层热对流系统传热与流动结构的实验

王牧; 陈阳; 王伟; 韦萍

doi:10.19527/j.cnki.2096-1642.1066

两层热对流系统传热与流动结构的实验

doi: 10.19527/j.cnki.2096-1642.1066

王牧¹,
陈阳¹,
王伟¹,
韦萍^1,2, ,

1. 同济大学航天航空与力学学院, 上海 200092;
2. 上海市地面交通工具空气动力与热环境模拟重点实验室, 上海 201804

基金项目:

国家自然科学基金面上项目(12272271)

详细信息

作者简介:
王牧(1995-)男,博士,研究Rayleigh-Bénard热对流,传热,立体三维重构。E-mail:1910092@tongji.edu.cn

通讯作者:
韦萍(1986-)女,教授,研究Rayleigh-Bénard热对流,转动湍流,传热。E-mail:16531@tongji.edu.cn

中图分类号: O357.5
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- 文章访问数: 53
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出版历程
- 收稿日期: 2023-06-16
- 修回日期: 2023-07-28
- 网络出版日期: 2023-08-31

Experiment for Heat Transport and Flow Structure of a Two-Layer Thermal Convection

WANG Mu¹,
CHEN Yang¹,
WANG Wei¹,
WEI Ping^{1,2
, ,}

1. School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092, China;
2. Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management Systems, Shanghai 201804, China

摘要

摘要: 双层热对流系统广泛存在于自然界中。为研究该系统的传热规律,刻画其中的流动结构特性,在矩形对流槽中使用甘油和2 cs硅油两种互不相溶的液体作为工作介质。位于底部的甘油液体层宽高比为10.4,其下表面是无滑移固液边界,上表面为滑移交界面,底部甘油层的实验参数为Rayleigh数Ra₁范围260 ≤Ra₁≤ 6 000,Prandtl数Pr₁范围3 708<Pr₁<7 000。硅油液体层的宽高比约为0.53,上表面为无滑移固液边界,硅油层Rayleigh数Ra₂范围1.5×10⁹ ≤ Ra₂ ≤ 2.0×10¹⁰,Prandtl数Pr₂范围28<Pr₂ <33。发现两层对流系统在两个区间下有不同的传热效率和流动状态。在区间1,即传热功率小于某个特定热流时,下面甘油层处于稳定层流状态。而在区间2,即传热功率大于该热流时,甘油层内液体处于不稳定对流状态。随着全局温差的增加,两层热对流系统的全局传热效率从区间1到区间2有一个突然的增加。甘油层的震荡失稳临界Ra数为1 523,这个数值小于无限大平板无滑移边界的理论预测值1 708。即滑移边界可使流体更不稳定,滑移边界使得硅油层的传热效率增加。采用阴影法对该系统内的对流斑图、交界面以及热羽流等流动结构进行了进一步刻画和分析。
- 热对流 /
- 滑移边界 /
- 传热 /
- 流动结构 /
- 流动状态
Abstract: Two-layer thermal convection exists widely in nature. In the present work, an experiment was conducted to inves- tigate the heat transport and flow structure in two-layer thermal convection. In a rectangular convection cell, two immiscible fluids, glycerol and 2 cs silicone oil, were used as the working fluids. In the lower-thin glycerol layer, the bottom boundary was subjected to a no-slip boundary condition (BC), and the interface was subjected to slip BC. The aspect ratio of glycerol layer (lower) was Γ₁=10.4. The Rayleigh number and Prandtl number of the glycerol layer covered the ranges of 260 ≤ Ra₁ ≤ 6 000 and 3 708<Pr₁<7 000, respectively. In the upper-thick silicone oil layer, the boundary at the top was subjected to no-slip BC. The aspect ratio of silicone oil (upper) was Γ₂=0.53. The Rayleigh number and Prandtl number of the silicone oil layer covered the ranges of 1.5×10⁹ ≤ Ra₂ ≤ 2.0×10¹⁰ and 28<Pr₂ <33. It is found that the two-layer thermal convection has different heat transfer efficiencies and flow structures in two regions. For region 1 where the heat flux is smaller than a certain value, the glycerol layer (lower) is in a stable stratified state. For region 2 where the heat flux is greater than the certain value, a cellular pattern was formed in glycerol layer and the global heat transport was sharply increased through a subcritical bifurcation. The heat transport of glycerol layer exhibits oscillatory instability at the critical Rayleigh number Ra_1c=1 523, which is smaller than the theoretic value 1 708 of critical value Ra for the 2D infinite Rayleigh-Bénard convection (RBC) with both rigid BCs. It reveals that the slip BC makes the fluid become unstable easier and enhances the heat transport. A measurement with shadowgraph method was further conducted. The cellular pattern of glycerol layer, the interface and hot plumes were also studied.
- thermal convection /
- slip boundary condition /
- heat transport /
- flow structure /
- flow state

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参考文献(21)

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两层热对流系统传热与流动结构的实验

doi: 10.19527/j.cnki.2096-1642.1066

作者简介:
王牧(1995-)男,博士,研究Rayleigh-Bénard热对流,传热,立体三维重构。E-mail:1910092@tongji.edu.cn

通讯作者:
韦萍(1986-)女,教授,研究Rayleigh-Bénard热对流,转动湍流,传热。E-mail:16531@tongji.edu.cn

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Experiment for Heat Transport and Flow Structure of a Two-Layer Thermal Convection

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两层热对流系统传热与流动结构的实验

doi: 10.19527/j.cnki.2096-1642.1066

作者简介: 王牧(1995-)男,博士,研究Rayleigh-Bénard热对流,传热,立体三维重构。E-mail:1910092@tongji.edu.cn

通讯作者: 韦萍(1986-)女,教授,研究Rayleigh-Bénard热对流,转动湍流,传热。E-mail:16531@tongji.edu.cn

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Experiment for Heat Transport and Flow Structure of a Two-Layer Thermal Convection

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出版历程

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联系我们

友情链接

作者简介:
王牧(1995-)男,博士,研究Rayleigh-Bénard热对流,传热,立体三维重构。E-mail:1910092@tongji.edu.cn

通讯作者:
韦萍(1986-)女,教授,研究Rayleigh-Bénard热对流,转动湍流,传热。E-mail:16531@tongji.edu.cn