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Journal of Porous Media
Fator do impacto: 1.49 FI de cinco anos: 1.159 SJR: 0.43 SNIP: 0.671 CiteScore™: 1.58

ISSN Imprimir: 1091-028X
ISSN On-line: 1934-0508

Volumes:
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Journal of Porous Media

DOI: 10.1615/JPorMedia.2018019236
pages 827-843

VISUALIZATION ANALYSIS OF NATURAL CONVECTION IN A POROUS ENCLOSURE USING THE CHEBYSHEV SPECTRAL COLLOCATION METHOD WITH TEMPERATURE-DEPENDENT THERMAL DIFFUSIVITY

Yuan-Yuan Chen
The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China; Key Laboratory of National Education Ministry for Electromagnetic Processing of Materials, Northeastern University, Shenyang 110819, China
Ben-Wen Li
Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, School of Energy and Power Engineering, Dalian University of Technology, Dalian, 116024, China
Jing-Kui Zhang
School of Environment and Municipal Engineering, Qingdao University of Technological, Qingdao 266033, China

RESUMO

We studied the effects of temperature-dependent thermal diffusivity and aspect ratio on natural convection in a rectangular porous cavity. Thermal diffusivity is assumed to vary as a linear function of temperature.We used the Chebyshev spectral collocation method to solve coupled nonlinear partial differential equations. The domain of the problem is discretized by Chebyshev–Gauss–Lobatto collocation points, and time derivatives are discretized by a semi-implicit scheme with finite-difference approximation. We executed the treatment of variable thermal diffusivity using array multiplication in the computation and used the matrix diagonalization method to solve discretized equations. Results from the current study are compared with those available in the literature. Numerical solutions are visualized using the isotherm, streamline, and heatline for different values of Rayleigh number, thermal diffusivity coefficient, and aspect ratio. For the first time, the visualization tool of heatline is applied to a porous enclosure with temperature-dependent thermal diffusivity. On the basis of these results, the heat-transfer process across the enclosure was analyzed. We found that variable thermal diffusivity has a considerable influence on flow pattern and corresponding heat transfer in the enclosure.