内圆柱旋转的Taylor-Couette系统中冷水热对流的数值模拟  

Numerical simulation for thermal convection of cold water in the Taylor-Couette system with a rotating inner cylinder

作　　者：仝家炜 曹玉会 TONG Jiawei;CAO Yuhui(School of Engineering Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大学工程科学学院,北京100049

出　　处：《中国科学院大学学报（中英文）》2024年第2期176-187,共12页Journal of University of Chinese Academy of Sciences

基　　金：国家自然科学基金(52176025)资助。

摘　　要：在内圆柱旋转的具有径向温度梯度的竖直环形腔中对10^(4)≤Ra≤10^(6),Re≤150范围内不同密度倒置参数下冷水的热对流开展三维数值模拟研究。环形腔的内外半径比η=0.5,高宽比Γ=8。研究结果表明,在离心力和浮力的共同作用下冷水系统中产生了丰富的三维流态,且与常规Oberbeck-Boussinesq流体的流动特征有明显差异。此外,旋转系统中离心作用导致的流态转变能够显著增强腔体中部的局部传热,进而极大地提高系统整体传热性能。在较高转速条件下,Ra的增加有时会导致系统传热性能呈现非单调变化趋势。The thermal convection of cold water has attracted considerable attention due to its relevance to engineering applications,such as the phase change cool storage device.However,the natural convection of cold water in the vertical annulus inherently has a minimum heat transfer rate due to the density inversion phenomenon of water near 4℃.It is feasible to reduce the negative effect of density inversion phenomenon on convective heat transfer by imposing a slow axial rotation on the inner cylinder.In order to better understand the heat transfer enhancement induced by the low-speed rotation of inner cylinder,three-dimensional numerical simulation was carried out to investigate the thermal convection of cold water near its density maximum in a finite vertical annulus with a heated rotating inner cylinder over a wide range of Rayleigh and Reynolds numbers(10^(4)≤Ra≤10^(6) and Re≤150)for various density inversion parameters.The radius ratio and aspect ratio of the annulus were 0.5 and 8,respectively.Results indicated that the combination of centrifugal and buoyancy forces led to multiple three-dimensional flow patterns in the cold water,which were distinct from the conventional Taylor-Couette flow under the Oberbeck-Boussinesq approximation.Furthermore,the transition of flow regimes in the rotating system was generally beneficial to heat transfer enhancement.However,at relatively high rotation speeds,the increase of Ra could result in the non-monotonic change of the overall heat transfer rate.

关 键 词：密度倒置 Taylor-Couette流动 数值模拟 传热 

分 类 号：TK124[动力工程及工程热物理—工程热物理]