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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Discussion on Conditions of Local Thermal Non-Equilibrium Effect in Porous Media

Get access (open in a dialog) DOI: 10.1615/IHTC15.pmd.009248
pages 6745-6759

Abstract

Macroscopic thermal modeling of convection in porous media includes local thermal equilibrium (LTE) model and local thermal non-equilibrium (LTNE) model. Temperature difference between solid and fluid is neglected in LTE model, while in LTNE model, special considerations are paid to this difference. In this work, previous researches on LTE/LTNE models are briefly reviewed and convective heat transfer in porous media based on LTE/LTNE models is numerically presented for forced convective heat transfer in a porous media tube with constant wall temperature. A relative deviation between Nusselt numbers of LTE and LTNE models is defined for analyzing LTNE effect. Temperature fields of solid and fluid and temperature difference field between solid and fluid are presented. Thermal performance of convective heat transfer with LTE model is compared with that of LTNE model. A parameter analysis is conducted for effects of porosity, pore density, duct scale, aspect ratio, Reynolds number and thermal conductivity ratio on heat transfer. The integrated conditions of conspicuous LTNE effect for porous media are put , which can directly guide thermal modeling on convection in different porous media. The measures lowering the proportion of local convective thermal resistance in total thermal resistance can weaken the LTNE effect in porous media. Numerical simulation for LTE model can be conducted more easily and efficiently compared with that for LTNE model but LTNE model is more accurate, especially when LTNE effect is conspicuous. At this point, determination of conditions of LTNE/LTE models in porous media is of great significance.