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浙江大学学报(工学版)
J4  2012, Vol. 46 Issue (3): 549-554    DOI: 10.3785/j.issn.1008-973X.2012.03.025
    
Direct simulation of natural convection
in square cavity filled with porous media
CHEN Kai, YU Zhao-sheng, SHAO Xue-ming
State Key Laboratory of Fluid Power Transmission and Control,Zhejiang University, Hangzhou 310027,China
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Abstract  

The structure of porous media was approximated by distributing solid particles in the cavity to study the heat transfer of natural convection in square porous media. And the fictitious domain method is used to resolve the equations of velocity and temperature. The influences of the particles’ number, distributing pattern and shape on heat transfer were analyzed. The heat of natural convection in square porous media at high Rayleigh number is mainly transferred by circumfluence around the boundary which is induced by the heat convection. The direct simulation reveals that when the Rayleigh number and the solid volume fraction are kept constant, the average Nusselt number of the boundary decreases when the particles, number increases in the particle regular distributing cases, which indicates the decrease of the heat transfer efficiency. Further flow field analysis shows that the distance between the outermost row of particles and the boundary has an important influence on the heat transfer efficiency.The heat transfer efficiency in the random particle distributing cases is higher than that in the regular particle distributing cases at a high Rayleigh number,when particles’ number and the solid volume fraction are same. The influence of the particle shape on heat transfer is slight．

Published: 01 March 2012
CLC:  V 211.1  
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Cite this article:

CHEN Kai, YU Zhao-sheng, SHAO Xue-ming. Direct simulation of natural convection
in square cavity filled with porous media. J4, 2012, 46(3): 549-554.

URL:

http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2012.03.025     OR     http://www.zjujournals.com/eng/Y2012/V46/I3/549


多孔介质方腔自然对流的直接数值模拟

为了研究多孔介质方腔的自然对流传热,通过在方腔内布置固体颗粒的方式来模拟多孔介质结构,并采用虚拟区域方法求解多孔介质中的流场和温度场,分析了固体颗粒的数目、布置方式和形状对传热效率的影响.在高Rayleigh数下,多孔介质方腔自然对流的传热主要是通过壁面附近热对流产生的环流.通过直接数值模拟研究发现：当保持Rayleigh数和固体体积分数不变时,随着模拟多孔介质的颗粒数目的增加,壁面平均Nusselt数随之减小,即传热效率降低,进一步的流场分析表明规则排列时最外排颗粒到壁面距离对于传热效率有重要的影响；当固体颗粒数目和体积分数相同时,颗粒随机布置在高Rayleigh数时比颗粒规则布置有更高的传热效率,而颗粒形状对于传热效率的影响则不大.

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