Flow Characteristics and Convection Heat Transfer in Microporous Media

2008 ◽  
Author(s):  
Pei-Xue Jiang ◽  
Rui-Na Xu ◽  
Chen-Ru Zhao
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Porous Media ◽  
Slip Flow ◽  
Convection Heat Transfer ◽  
Flow Characteristics ◽  
Flow In Porous Media ◽  
Convection Heat ◽  
Microporous Media ◽  
Internal Convection

The flow characteristics of water and air in micro porous tubes with average diameters of 200 μm ∼ 10 μm were studied experimentally and numerically. The results showed that compressibility significantly influence the air flow in porous media with the particle diameters of 200 μm ∼ 10 μm, which increases the friction factor in porous media. Rarefaction effects occur in air flows in the microporous media with particle diameters less than 90 μm. New correlations for K and F were proposed with consideration of Kn. The numerically predicted friction factors for the slip-flow regime in the micro-porous media with 90 μm ∼ 10 μm diameter particles were less than the known correlation and close to the experimental data. The internal convection heat transfer coefficients between particles and fluid in the micro porous media were determined experimentally and numerically. The experimental data for the micro porous media with particle diameters of 20 and 10 μm are much lower than the previously published results. A new correlation for Nusslet number was proposed with consideration of the influence of Kn. Numerical calculation with consideration of slip-flow and temperature jump in micro porous media can properly simulate internal convection heat transfer.

scholarly journals Experimental study of forced convection heat transport in porous media

2017 ◽  
Author(s):  
Nicola Pastore ◽  
Claudia Cherubini ◽  
Dimitra Rapti ◽  
Concetta I. Giasi
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Experimental Study ◽  
Porous Medium ◽  
Porous Media ◽  
Heat Transport ◽  
Forced Convection ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Forced Convection Heat Transfer

Abstract. The knowledge of the dynamics of forced convection heat transfer in porous media is relevant in order to optimize the efficiency of geothermal installations in aquifers. In some applications groundwater is used directly as thermal fluid. The system uses one or several drilling holes to pump and deliver groundwater with a heat exchange system at surface (open loop). Other applications use vertical borehole heat exchangers without injection or extraction of groundwater (closed loop). In both systems the convection flow dynamics in porous media play an important role on the heat production. The present study is aimed at extending this thematic issue through heat transport experiments and their interpretation at laboratory scale. An experimental study to evaluate the dynamics of forced convection heat transfer in a thermally isolated column filled with porous medium has been carried out. The behavior of two porous media having different grain sizes and specific surfaces has been observed. The experimental data have been compared with an analytical solution for one dimensional heat transport for local non thermal equilibrium condition. The interpretation of the experimental data shows that, the heterogeneity of the porous medium affects heat transport dynamics causing a channeling effect which has consequences on thermal dispersion phenomena and heat transfer between fluid and solid phases limiting the capacity to store or dissipate heat in the porous medium.

Experimental Investigation of Fluid Flow and Internal Convection Heat Transfer in Mini/Micro Porous Media

2009 ◽  
Author(s):  
Yu-Li Huang ◽  
Pei-Xue Jiang ◽  
Rui-Na Xu
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Porous Media ◽  
Fluid Flow ◽  
Convection Heat Transfer ◽  
Reynolds Numbers ◽  
Solid Particles ◽  
Convection Heat ◽  
Friction Factors ◽  
Internal Convection

The flow characteristics of different gases such as air, helium and carbon dioxide and internal convection heat transfer between the solid particles and the fluid in mini/micro porous media were studied experimentally. The test sections for fluid flow and heat transfer were made of sintered bronze particles with average diameters of 225 μm, 125 μm, 90 μm and 40 μm. The experimentally measured friction factors with consideration of compressibility for air, helium and carbon dioxide in the porous media with average diameters of 225 μm and 125 μm agree well with the known correlation for normal size porous media (the correlation of Aerov and Tojec), especially at the relatively high Reynolds numbers. The experimentally measured friction factors for air, helium and carbon dioxide in the porous media with average diameters of 90 μm are slightly less than the correlation of Aerov and Tojec at the relatively low Reynolds numbers. The experimental values for the friction factors for air, helium and carbon dioxide in the microporousmedia with 40 μm average diameters are much less than the correlation of Aerov and Tojec. The results show that rarefaction effects occur in air, helium and hydrogen flows in the microporous media with particle diameters less than 90 μm. The internal convection heat transfer coefficients between particles and fluid for air, helium and carbon dioxide in the micro porous media were determined experimentally.

scholarly journals Experimental study of forced convection heat transport in porous media

2018 ◽  
Vol 25 (2) ◽  
pp. 279-290 ◽  
Author(s):  
Nicola Pastore ◽  
Claudia Cherubini ◽  
Dimitra Rapti ◽  
Concetta I. Giasi
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Experimental Study ◽  
Porous Medium ◽  
Porous Media ◽  
Heat Transport ◽  
Forced Convection ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Transport Dynamics

Abstract. The present study is aimed at extending this thematic issue through heat transport experiments and their interpretation at laboratory scale. An experimental study to evaluate the dynamics of forced convection heat transfer in a thermally isolated column filled with porous medium has been carried out. The behavior of two porous media with different grain sizes and specific surfaces has been observed. The experimental data have been compared with an analytical solution for one-dimensional heat transport for local nonthermal equilibrium condition. The interpretation of the experimental data shows that the heterogeneity of the porous medium affects heat transport dynamics, causing a channeling effect which has consequences on thermal dispersion phenomena and heat transfer between fluid and solid phases, limiting the capacity to store or dissipate heat in the porous medium.

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