Heat conduction in granular materials

Vargas, Watson L.; McCarthy, Joseph J.

doi:10.1002/aic.690470511

Cited by 245 publications

(114 citation statements)

References 55 publications

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“…3. Numerical modeling of such structures has also been developed, [4][5][6] but in the end one has always relied previously on experimental work when effective thermal conductivity of porous materials has been needed. [7][8][9] The question still remains open, however, how well the analytical (averaged) expressions describe the properties of real porous materials.…”

Section: Introductionmentioning

confidence: 99%

Dependence of thermal conductivity on structural parameters in porous samples

et al. 2012

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The in-plane thermal conductivity of porous sintered bronze plates was studied both experimentally and numerically. We developed and validated an experimental setup, where the sample was placed in vacuum and heated while its time-dependent temperature field was measured with an infrared camera. The porosity and detailed three-dimensional structure of the samples were determined by X-ray microtomography. Lattice-Boltzmann simulations of thermal conductivity in the tomographic reconstructions of the samples were used to correct the contact area between bronze particles as determined by image analysis from the tomographic reconstructions. Small openings in the apparent contacts could not be detected with the imaging resolution used, and they caused an apparent thermal contact resistance between particles. With this correction included, the behavior of the measured thermal conductivity was successfully explained by an analytical expression, originally derived for regular structures, which involves three structural parameters of the porous structures. There was no simple relationship between heat conductivity and porosity.

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Section: Introductionmentioning

confidence: 99%

Dependence of thermal conductivity on structural parameters in porous samples

et al. 2012

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“…Thermal Discrete Element Method was introduced in [11,12,13] to investigate the effective thermal conductivity of granular materials under static loading and in rotating tumblers [14]. We recently used it in [15,10] to study the heat transfer in granular flows.…”

Section: Simulation Of Heat Transfer In Granular Flowmentioning

confidence: 99%

“…The heat flux φ i j [W] between two contacting grains is described by the model of conductance for perfectly smooth contacts [16,11,12,15,10]: We used the thermal-DEM to simulate the shear flow of 5000 spheres, applying a constant shear rateγ and a constant normal stress σ yy (see Fig. 1a).…”

Section: Simulation Of Heat Transfer In Granular Flowmentioning

confidence: 99%

Eddies, mixing and heat transfer in dense granular flows

Rognon¹,

Miller²,

Einav³

2013

AIP Conference Proceedings

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Abstract. We investigate the ability of dense granular flows to transfer heat while flowing. Using discrete element simulations, we show that large correlated motions of grains develop in dense granular sheared layer, and lead to a strong heat transfer across streamlines. This process is similar to the convection induced by eddies in turbulent flows. However, granular eddies do not result from visco-inertial instability, but from the steric exclusion of closely packed grains. As a result, they seem to develop even at very low shear rates, which could have a significant practical interest. Beyond their different natures, classical turbulence and granular turbulence face similar challenges, and it is hoped that research in these two fields can benefit from each other.

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“…An extension of this method was proposed by [5,7] that enables the transfer of heat along grain contacts by a simple Fourier law of conduction (Fig. 4).…”

Section: Thermal-demmentioning

confidence: 99%

“…Significant research focused on their effective conductivity, as it was assumed to be the most important factor in granular materials [1,2]. More recently this has been studied using discrete element model (DEM) simulations [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

10,000 – A reason to study granular heat convection

Einav¹,

Rognon²,

Gan³

et al. 2013

AIP Conference Proceedings

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Abstract. In sheared granular media, particle motion is characterized by vortex-like structures; here this is demonstrated experimentally for disks system undergoing indefinite deformation during simple shear, as often imposed by the rock masses hosting earthquake fault gouges. In traditional fluids it has been known for years that vortices represent a major factor of heat transfer enhancement via convective internal mixing, but in analyses of heat transfer through earthquake faults and base planes of landslides this has been continuously neglected. Can research proceed by neglecting heat convection by internal mixing? Our answer is astonishingly far from being yes.

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Heat conduction in granular materials

Abstract: Heat transfer in particulate systems is important to a ®ast array of industries, yet is

Cited by 245 publications

References 55 publications

Dependence of thermal conductivity on structural parameters in porous samples

Dependence of thermal conductivity on structural parameters in porous samples

Eddies, mixing and heat transfer in dense granular flows

10,000 – A reason to study granular heat convection

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