Conductivity of granular media with stagnant interstitial fluids via thermal particle dynamics simulation

Vargas, Watson L.; McCarthy, Joseph J.

doi:10.1016/s0017-9310(02)00175-8

Cited by 98 publications

(50 citation statements)

References 25 publications

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“…However, examples of the DEM in thermal fields are mostly focused on problems involving granular materials [7,13,14,15,16,17], with the exception of [18], in which the mathematical proof of the 2D DEM for a continuous thermal field is described.…”

Section: Introductionmentioning

confidence: 99%

Simulation of continuum heat conduction using DEM domains

Terreros

Iordanoff

Charles

2013

Computational Materials Science

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Currently, almost all material manufacturing processes are simulated using methods based on continuum approaches such as the Finite Element Method (FEM). These methods, though widely studied, face difficulties with multibody, contact, high-strain and high-displacement problems, which are usually found in manufacturing processes. In some cases, the Discrete Element Method (DEM) is used to overcome these problems, but it is not yet able to simulate some of the physics of a continuum material, such as 3D heat transfer.To carry out a realistic simulation of a process, its thermal field must be properly predicted. This work describes a fast and efficient method to simulate heat conduction through a 3D continuum material using the Discrete Element Method. The material is modelled with spherical discrete elements of different sizes to obtain a compact and isotropic domain adequate for carrying out mechanical simulations to obtain straightforward thermal and mechanical coupling.Thermal simulations carried out with the proposed Discrete Element Method are compared to both the analytical and FEM results. This comparison shows excellent agreement and validates the proposed method.

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Section: Introductionmentioning

confidence: 99%

Simulation of continuum heat conduction using DEM domains

Terreros

Iordanoff

Charles

2013

Computational Materials Science

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“…(1) for every single particle of a granular assembly is not feasible, simplifying assumptions have to be made. Simsek et al [8], Peters [9], Vargas and McCarthy [10] and Shimizu [11] use the lumped capacitance method. Each particle has a spatially uniform temperature; temperature gradients within the particle are negligible, providing infinitely fast heat propagation.…”

Section: Lumped Capacitance Methodsmentioning

confidence: 99%

Utilization of a Radial Temperature Model for Heat Conduction within Spherical Particles to Model Granular Assemblies

et al. 2008

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A heat transfer (DEM) model for application in the particle based discrete element simulation method is presented. It utilizes an analytical solution of the heat diffusion equation for a solid spherical particle to obtain temporal and radial solutions of the temperature distributions within the particles. This radial temperature model avoids the shortcomings of the usual assumption of spatially uniform temperature profiles in particles. The concept is designed to minimize computing power and memory requirement in order to allow the computation of granular assemblies consisting of a large number of particles. Results obtained for a particle subject to transient convective boundary conditions are compared with a Crank-Nicholson implicit scheme as numerical reference solution. A first implementation of the radial temperature model in a discrete element code reveals the additional computational cost as negligible compared to the demands of contact identification and force calculation. IntroductionHeat transfer in granular media occurs in a wide range of applications such as catalytic packed beds, combustion of solid biomass, in recuperators or in sintering processes. It is common practice to describe the motion and the thermal behavior of the granular media by continuum models. These are based on the Eulerian approach, with the granular medium described as continuous functions of time and space.This macroscopic view leads to averaged values in time and space for the transport of mass, momentum, energy and species as well as "effective" material properties [1,2]. While providing satisfactory results for stationary granular materials such as packed beds, these approaches need empirical corrections, more or less arbitrary modeling, or even fail when modeling granular media in motion and transient heat transfer [3,4]. Anisotropic effects like mixing and segregation as well as the evolution of stress chains and heat convection by particle motion cannot be properly accounted for [5].Approaches using the Lagrangian view like the discreteelement method (DEM) do not suffer from these restrictions.In the DEM, each single particle and its interaction with the surrounding is subject to an individual description [6,7]. The equations of motion are applied to each particle and solved numerically. For extending this method to heat transfer, mechanisms such as convection between particles and the interstitial fluid or contact heat transfer between particles as well as conduction within a particle must be modeled. The conduction within a single particle is a matter of high technical importance as it characterizes the transient behavior of the granular media. The local temperature within the particle governs, for example, drying processes or the release of volatile matter within solid fuel particles. AnalysisIn the following, the analysis concentrates on spherical particles, a very common particle geometry in DEM simulations.A single particle subject to transient boundary conditions will develop a transient temperature distribution th...

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“…Interparticle heat exchange between particles i and j consists of heat transfer through a contacting surface Qct and heat conduction through the surrounding gas layer Qcd. [20][21][22][23][24] The reaction heat Qreac is calculated from the enthalpy change in each chemical equation:…”

Section: Heat Transfer Of Particlesmentioning

confidence: 99%

Effect of High Reactivity Coke for Mixed Charge in Ore Layer on Reaction Behavior of Each Particle in Blast Furnace

et al. 2013

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A low coke rate operation in blast furnace is desired to decrease the carbon input and mitigate global warming problem. However, low coke rate operation tends to cause the gas permeability to deteriorate. The mixing of small-size coke (nut coke) including high reactivity coke in ore layer is considered to be a promising way to improve permeability and increase reaction efficiency in a blast furnace. Although adding a nut coke mixing to an ore layer is predicted to be empirically effective in low coke rate operation, there is little actual data on microscopic phenomena of each particle in the packed bed. In the present study, an Euler-Lagrange approach was introduced to precisely understand the influence of the packed bed structure on the reaction behavior of each particle in the three-dimensional particle arrangement.It was observed that the heterogeneity on the reaction rate and temperature distribution was influenced by the particle arrangement. When high-reactivity coke was used at approximately 1 273 K, although CO gas fraction increased, the gaseous phase temperature decreased due to the active solution loss reaction rate of the nut coke in the mixed layer. As a result, the ore reduction rate decreased. The contribution of high-reactivity coke to the ore reduction rate depends on the particle arrangement through the heat transfer and reaction heat. Accordingly, in the case of the mixed charge of the high reactivity nut coke in the ore layer, the design of the packed bed structure is important.

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Conductivity of granular media with stagnant interstitial fluids via thermal particle dynamics simulation

Cited by 98 publications

References 25 publications

Simulation of continuum heat conduction using DEM domains

Simulation of continuum heat conduction using DEM domains

Utilization of a Radial Temperature Model for Heat Conduction within Spherical Particles to Model Granular Assemblies

Effect of High Reactivity Coke for Mixed Charge in Ore Layer on Reaction Behavior of Each Particle in Blast Furnace

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