The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Michel Quintard - One of the best experts on this subject based on the ideXlab platform.
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Effect of solid thermal conductivity and Particle–Particle Contact on effective thermodiffusion coefficient in porous media
International Journal of Thermal Sciences, 2011Co-Authors: Hossein Davarzani, Manuel Marcoux, Michel QuintardAbstract:Transient mass transfer associated to a thermal gradient through a saturated porous medium is studied experimentally and theoretically to determine the effect of solid thermal conductivity and Particle-Particle Contact on thermodiffusion processes. In this study, the theoretical volume averaging model developed in a previous study has been adopted to determine the effective transport coefficients in the case of Particle-Particle Contact configurations. The theoretical results revealed that the effective thermodiffusion coefficient is independent of the thermal conductivity ratio for pure diffusive cases. In all cases, even if the effective thermal conductivity depends on the Particle-Particle Contact, the effective thermodiffusion coefficient remains independent of the solid phase connectivity. We also found that the porosity can change the impact of dispersion effects on the thermodiffusion coefficients. For large values of the thermal conductivity contrast, dispersion effects are negligible and the effective thermal conductivity coefficients are the same as the ones for the pure diffusion case. Experimental results obtained for the purely diffusive case, using a special two-bulb apparatus, confirm the theoretical results. These results also show that, for non-consolidated porous media made of spheres, the thermal conductivity ratio has no significant influence on the thermodiffusion process for pure diffusion. Finally, the Particle-Particle Contact also does not show a considerable influence on the thermodiffusion process.
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Effect of solid thermal conductivity and Particle-Particle Contact on effective thermodiffusion coefficient in porous media
International Journal of Thermal Sciences, 2011Co-Authors: Hossein Davarzani, Manuel Marcoux, Michel QuintardAbstract:Transient mass transfer associated to a thermal gradient through a saturated porous medium is studied experimentally and theoretically to determine the effect of solid thermal conductivity and Particle-Particle Contact on thermodiffusion processes. In this study, the theoretical volume averaging model developed in a previous study has been adopted to determine the effective transport coefficients in the case of Particle-Particle Contact configurations. The theoretical results revealed that the effective thermodiffusion coefficient is independent of the thermal conductivity ratio for pure diffusive cases. In all cases, even if the effective thermal conductivity depends on the Particle-Particle Contact, the effective thermodiffusion coefficient remains independent of the solid phase connectivity. We also found that the porosity can change the impact of dispersion effects on the thermodiffusion coefficients. For large values of the thermal conductivity contrast, dispersion effects are negligible and the effective thermal conductivity coefficients are the same as the ones for the pure diffusion case. Experimental results obtained for the purely diffusive case, using a special two-bulb apparatus, confirm the theoretical results. These results also show that, for non-consolidated porous media made of spheres, the thermal conductivity ratio has no significant influence on the thermodiffusion process for pure diffusion. Finally, the Particle-Particle Contact also does not show a considerable influence on the thermodiffusion process.
Hossein Davarzani - One of the best experts on this subject based on the ideXlab platform.
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Effect of solid thermal conductivity and Particle–Particle Contact on effective thermodiffusion coefficient in porous media
International Journal of Thermal Sciences, 2011Co-Authors: Hossein Davarzani, Manuel Marcoux, Michel QuintardAbstract:Transient mass transfer associated to a thermal gradient through a saturated porous medium is studied experimentally and theoretically to determine the effect of solid thermal conductivity and Particle-Particle Contact on thermodiffusion processes. In this study, the theoretical volume averaging model developed in a previous study has been adopted to determine the effective transport coefficients in the case of Particle-Particle Contact configurations. The theoretical results revealed that the effective thermodiffusion coefficient is independent of the thermal conductivity ratio for pure diffusive cases. In all cases, even if the effective thermal conductivity depends on the Particle-Particle Contact, the effective thermodiffusion coefficient remains independent of the solid phase connectivity. We also found that the porosity can change the impact of dispersion effects on the thermodiffusion coefficients. For large values of the thermal conductivity contrast, dispersion effects are negligible and the effective thermal conductivity coefficients are the same as the ones for the pure diffusion case. Experimental results obtained for the purely diffusive case, using a special two-bulb apparatus, confirm the theoretical results. These results also show that, for non-consolidated porous media made of spheres, the thermal conductivity ratio has no significant influence on the thermodiffusion process for pure diffusion. Finally, the Particle-Particle Contact also does not show a considerable influence on the thermodiffusion process.
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Effect of solid thermal conductivity and Particle-Particle Contact on effective thermodiffusion coefficient in porous media
International Journal of Thermal Sciences, 2011Co-Authors: Hossein Davarzani, Manuel Marcoux, Michel QuintardAbstract:Transient mass transfer associated to a thermal gradient through a saturated porous medium is studied experimentally and theoretically to determine the effect of solid thermal conductivity and Particle-Particle Contact on thermodiffusion processes. In this study, the theoretical volume averaging model developed in a previous study has been adopted to determine the effective transport coefficients in the case of Particle-Particle Contact configurations. The theoretical results revealed that the effective thermodiffusion coefficient is independent of the thermal conductivity ratio for pure diffusive cases. In all cases, even if the effective thermal conductivity depends on the Particle-Particle Contact, the effective thermodiffusion coefficient remains independent of the solid phase connectivity. We also found that the porosity can change the impact of dispersion effects on the thermodiffusion coefficients. For large values of the thermal conductivity contrast, dispersion effects are negligible and the effective thermal conductivity coefficients are the same as the ones for the pure diffusion case. Experimental results obtained for the purely diffusive case, using a special two-bulb apparatus, confirm the theoretical results. These results also show that, for non-consolidated porous media made of spheres, the thermal conductivity ratio has no significant influence on the thermodiffusion process for pure diffusion. Finally, the Particle-Particle Contact also does not show a considerable influence on the thermodiffusion process.
Jin Sun - One of the best experts on this subject based on the ideXlab platform.
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shear thickening regimes of dense non brownian suspensions
Soft Matter, 2016Co-Authors: Christopher Ness, Jin SunAbstract:We propose a unifying rheological framework for dense suspensions of non-Brownian spheres, predicting the onsets of Particle friction and Particle inertia as distinct shear thickening mechanisms, while capturing quasistatic and soft Particle rheology at high volume fractions and shear rates respectively. Discrete element method simulations that take suitable account of hydrodynamic and Particle-Contact interactions corroborate the model predictions, demonstrating both mechanisms of shear thickening, and showing that they can occur concurrently with carefully selected Particle surface properties under certain flow conditions. Microstructural transitions associated with frictional shear thickening are presented. We find very distinctive divergences of both microstructural and dynamic variables with respect to volume fraction in the thickened and non-thickened states.
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Shear thickening regimes of dense non-Brownian suspensions
Soft matter, 2015Co-Authors: Christopher Ness, Jin SunAbstract:We propose a unifying rheological framework for dense suspensions of non-Brownian spheres, predicting the onsets of Particle friction and Particle inertia as distinct shear thickening mechanisms, while capturing quasistatic and soft Particle rheology at high volume fractions and shear rates respectively. Discrete element method simulations that take suitable account of hydrodynamic and Particle-Contact interactions corroborate the model predictions, demonstrating both mechanisms of shear thickening, and showing that they can occur concurrently with carefully selected Particle surface properties under certain flow conditions. Microstructural transitions associated with frictional shear thickening are presented. We find very distinctive divergences of both the microstructural and dynamic variables with respect to volume fraction in the thickened and non-thickened states.
J. Sundberg - One of the best experts on this subject based on the ideXlab platform.
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Inter‐Particle Contact heat transfer model: an extension to soils at elevated temperatures
International Journal of Energy Research, 2005Co-Authors: W. H. Leong, V.-r. Tarnawski, Fabio Gori, G. D. Buchan, J. SundbergAbstract:A simple 'inter-Particle Contact heat transfer' model for predicting effective thermal conductivity of soils at moderate temperatures (0-30degreesC) has been extended up to 90degreesC. The extended model accounts for latent heat transport by water vapour diffusion in soil air above the permanent wilting point; below that point, the soil thermal conductivity is approximated by linear interpolation without latent heat effect. By and large the best results are obtained when the latent heat is used only in the 'self consistent approximation' model with an overall root mean square error of 35% for all soils under consideration or 26% when excluding volcanic soils. This option can also be applied to moderate temperatures at which the enhanced heat transfer is negligibly small. Copyright (C) 2005 John Wiley Sons, Ltd.
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Inter-Particle Contact heat transfer in soil systems at moderate temperatures
International Journal of Energy Research, 2002Co-Authors: V.-r. Tarnawski, W. H. Leong, Fabio Gori, G. D. Buchan, J. SundbergAbstract:An inter-Particle Contact heat transfer model for evaluating soil thermal conductivity is analysed with respect to soils, representing different textural classes, exposed to moderate temperatures ranging from 15 to 30°C. This model is a combination of a self-consistent approximation model, enhanced with an inter-Particle Contact heat transfer correction coefficient. For dry and saturated soils, this coefficient is defined as a ratio of a soil harmonic mean thermal conductivity of solid and fluid (air or water) phases, to the average thermal conductivity of soil solid grains. For unsaturated soils, we assume a linear interpolation of the correction coefficient between absolutely dry and saturated states, with a Kersten function (Ke) as a proportional factor. The strongest impact of the correction coefficient (maximum reduction of heat transfer) is observed for coarse soils below a critical value of saturation degree (Sr-cr–corresponds to Ke≅0) followed by medium and fine soils. For Sr>Srcr, the reduction of heat transfer gradually diminishes as Sr approaches 1 (i.e. saturated state). Soil texture, soil specific surface area, porosity and mineralogical composition (particularly quartz content) are important factors influencing the heat transfer correction coefficient. Their influence appears to be more substantial at the lower half of the wetness range (Sr
Manuel Marcoux - One of the best experts on this subject based on the ideXlab platform.
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Effect of solid thermal conductivity and Particle–Particle Contact on effective thermodiffusion coefficient in porous media
International Journal of Thermal Sciences, 2011Co-Authors: Hossein Davarzani, Manuel Marcoux, Michel QuintardAbstract:Transient mass transfer associated to a thermal gradient through a saturated porous medium is studied experimentally and theoretically to determine the effect of solid thermal conductivity and Particle-Particle Contact on thermodiffusion processes. In this study, the theoretical volume averaging model developed in a previous study has been adopted to determine the effective transport coefficients in the case of Particle-Particle Contact configurations. The theoretical results revealed that the effective thermodiffusion coefficient is independent of the thermal conductivity ratio for pure diffusive cases. In all cases, even if the effective thermal conductivity depends on the Particle-Particle Contact, the effective thermodiffusion coefficient remains independent of the solid phase connectivity. We also found that the porosity can change the impact of dispersion effects on the thermodiffusion coefficients. For large values of the thermal conductivity contrast, dispersion effects are negligible and the effective thermal conductivity coefficients are the same as the ones for the pure diffusion case. Experimental results obtained for the purely diffusive case, using a special two-bulb apparatus, confirm the theoretical results. These results also show that, for non-consolidated porous media made of spheres, the thermal conductivity ratio has no significant influence on the thermodiffusion process for pure diffusion. Finally, the Particle-Particle Contact also does not show a considerable influence on the thermodiffusion process.
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Effect of solid thermal conductivity and Particle-Particle Contact on effective thermodiffusion coefficient in porous media
International Journal of Thermal Sciences, 2011Co-Authors: Hossein Davarzani, Manuel Marcoux, Michel QuintardAbstract:Transient mass transfer associated to a thermal gradient through a saturated porous medium is studied experimentally and theoretically to determine the effect of solid thermal conductivity and Particle-Particle Contact on thermodiffusion processes. In this study, the theoretical volume averaging model developed in a previous study has been adopted to determine the effective transport coefficients in the case of Particle-Particle Contact configurations. The theoretical results revealed that the effective thermodiffusion coefficient is independent of the thermal conductivity ratio for pure diffusive cases. In all cases, even if the effective thermal conductivity depends on the Particle-Particle Contact, the effective thermodiffusion coefficient remains independent of the solid phase connectivity. We also found that the porosity can change the impact of dispersion effects on the thermodiffusion coefficients. For large values of the thermal conductivity contrast, dispersion effects are negligible and the effective thermal conductivity coefficients are the same as the ones for the pure diffusion case. Experimental results obtained for the purely diffusive case, using a special two-bulb apparatus, confirm the theoretical results. These results also show that, for non-consolidated porous media made of spheres, the thermal conductivity ratio has no significant influence on the thermodiffusion process for pure diffusion. Finally, the Particle-Particle Contact also does not show a considerable influence on the thermodiffusion process.