Numerical simulation of natural convection of latent heat phase-change-material microcapsulate slurry packed in a horizontal rectangular enclosure heated from below and cooled from above
Numerical simulation of natural convection of latent heat phase-change-material microcapsulate slurry packed in a horizontal rectangular enclosure heated from below and cooled from above
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DOI：
10.1007/s00231-006-0121-y
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发表时间：
2007-01
影响因子：
2.2
通讯作者：
H. Inaba;Yanlai Zhang;A. Horibe;N. Haruki
中科院分区：
文献类型：
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作者：
H. Inaba;Yanlai Zhang;A. Horibe;N. Haruki
以具有潜热容的非牛顿相变材料（PCM）微胶囊浆料为研究对象，对从下加热到上冷却的矩形密闭空间内的自然对流进行了二维数值模拟。采用有限体积法建立了无量纲坐标系下的数学模型，并对控制方程进行了离散化。讨论了PCM微胶囊浆的自然对流和传热特性，发现PCM微胶囊浆具有非牛顿流体的伪塑性特性，且具有峰值的潜热比热容。假设PCM微胶囊浆体的黏度遵循Ostwald-de Waele幂律流体模型，幂律指标为幂律，稠度系数为k。讨论了相变材料、质量浓度和展弦比Ar对自然对流换热的影响。通过与未发生相变的微胶囊浆的结果对比，发现在相变温度范围内，发生相变的微胶囊浆的传热增强。数值模拟的参数范围为：箱体宽高比Ar为2 ~ 20，料浆质量浓度scm10 ~ 40%，料浆幂律指数n0为0.89 ~ 1.0，瑞利数Ra为103 ~ 107。
A two-dimensional numerical simulation of natural convection in a rectangular enclosure heated from below and cooled from above has been conducted with non-Newtonian phase-change-material (PCM) microcapsulate slurry with latent heat capacities. The formulation of the mathematical model in dimensionless co-ordinates and discretization of the governing equations have been done using the finite volume method. Both natural convection and heat transfer characteristics are discussed about natural convection with PCM microcapsulate slurry, which exhibits the pseudoplastic non-Newtonian fluid behavior and a peak value in the specific heat capacity with latent heat. The viscosity of the present PCM microcapsulate slurry is assumed to follow the Ostwald-de Waele power law fluid model with the power-law indexnand the consistency coefficientK. The effects of phase-change material, the mass concentration, and the aspect ratio Ar on the natural convection heat transfer are described, respectively. By comparing with the results of microcapsule slurry without phase change, the enhancement in heat transfer is found in microcapsule slurry with phase change during the phase change temperature range. Numerical simulations are performed in the following parametric ranges: the width–height aspect ratio of the enclosure Ar from 2 to 20, the mass concentrationsCmof the slurry from 10 to 40%, power law indexnof the slurry from 0.89 to 1.0 and Rayleigh numbers Ra ranges from 103to 107.