Development and verification of a resolved 3D inner particle heat transfer model for the Discrete Element Method (DEM)

Oschmann, Tobias; Schiemann, Martin; Kruggel‐Emden, Harald

doi:10.1016/j.powtec.2015.12.008

Cited by 48 publications

(21 citation statements)

References 58 publications

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“…The discrete element method (DEM) is a numerical technique that resolves each individual particle motion in a particulate system that contains a collection of particles. Heat transfer and chemical reactions can also be resolved at the particle scale with advanced particle-scale models [35,36] which extend the capabilities of DEM. With regard to particle dynamics, the DEM model in this work is based on the so-called soft sphere approach that has been implemented in LIGGGHTS [37].…”

Section: Discrete Element Methods (Dem)mentioning

confidence: 99%

Numerical study of particle mixing in a lab-scale screw mixer using the discrete element method

Heindel

Wright

2017

Powder Technology

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This study employs the Discrete Element Method (DEM) to simulate particulate flow and investigate mixing performance of a lab-scale double screw mixer. The simulation employs polydispersed biomass and glass bead particles based on experiments conducted in previous studies. Visual examination of particle distribution and statistical analysis of particle residence times of experimental data served as model validation. Statistical analysis indicates a maximum 9.8% difference between the experimental and simulated biomass particle mean residence time, and visual observations suggest the simulation captures the particle mixing trends observed in the experiments. Results indicate that the particle mean mixing time, non-dimensionalized by ideal flow time in the plug flow reactor, varies between 1.008 and 1.172, and it approaches 1 with increasing biomass feed rate. The mixing index profile in the axial direction shows a mixing-demixing-mixing oscillation pattern. Increasing screw pitch length is detrimental to mixing performance; decreasing the solid particle feed rate reduces the mixing degree; and increasing the biomass to glass bead size ratio decreases mixing performance. A comparison of a binary, single-sized biomass and glass particles mixture to a multicomponent mixture indicates that the binary system has similar mixing pattern as a multicomponent system. These findings demonstrate that DEM is a valuable tool for the design and simulation of double screw mixing systems.

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Section: Discrete Element Methods (Dem)mentioning

confidence: 99%

Numerical study of particle mixing in a lab-scale screw mixer using the discrete element method

Heindel

Wright

2017

Powder Technology

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“…As pointed out by Schmidt et al [35], as well as Oschmann et al [23], the computational cost for a fully resolved particle is enormous: calculation time and data storage increase by a factor of about 1000 when using three-dimensionally resolved simulations. Fortunately, a one-dimensional discretization (as followed in the current work) is often an excellent approximation (in case of a sphere) when considering heat exchange in a certain Reynolds number range (see Nikrityuk et al [36]).…”

Section: Effect Of Heat Conduction Within the Particlementioning

confidence: 99%

“…Relevant studies include the work of Feng et al [21,22] or Oschmann et al [23]. The former propose a so-called discrete thermal element model (DTEM), which can be readily integrated with the DEM.…”

Section: Introductionmentioning

confidence: 99%

Heat transfer rates in sheared beds of inertial particles at high Biot numbers

et al. 2017

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We investigate heat conduction rates through the contact network of sheared granular materials that consist of particles with a density much larger than that of the ambient fluid. The tool ParScale, a finite difference solver for intra-particle transport processes, is coupled to the discrete element method solver LIGGGHTS to carry out the simulations. Heat transfer to the surrounding fluid is considered via a fixed heat transfer coefficient. We identify a combination of Biot and Peclet number as the key non-dimensional influence parameter to describe the non-dimensional heat flux through the particle bed and provide an analytical solution to calculate mean particle temperature profiles. Simulations over a wide range of particle volume fractions, Biot and Peclet numbers are then performed in order to develop a continuum model for the heat flux. We show that for Biot numbers below 10 −3 our results agree with a simple model based on a uniform particle temperature. However, for Biot numbers above a certain threshold, the conductive heat flux decreases substantially depending on the flow situation, and temperature gradients within the particle should be considered in order to correctly predict the heat transfer rate to the surrounding fluid.

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“…Note that an inherent assumption of Eq. (9) is an isothermal particle or Biot number << 1 (i.e., no spatial temperature gradients within a particle); the methods developed here can also be adapted to non-isothermal particles as developed by [16].…”

Section: Solid Phasementioning

confidence: 99%

A coupled, multiphase heat flux boundary condition for the discrete element method

Lattanzi

Hrenya

2016

Chemical Engineering Journal

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Similar to single-phase flows, multiphase systems with a constant heat flux at the wall are common in practice. Unlike single-phase flows, however, the numerical implementation of a constant boundary flux is non-trivial due to the coupling between phases-i.e., the partition of total flux between the phases can vary in space and time. A numerical technique for modeling such a boundary condition is proposed here and verified via simulations of gas-solid flows. While discrete-particle simulations of monodisperse particles are considered here, the technique can be extended to include radiation, polydisperse systems, and/or a continuum representation of the solids phase.

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Development and verification of a resolved 3D inner particle heat transfer model for the Discrete Element Method (DEM)

Cited by 48 publications

References 58 publications

Numerical study of particle mixing in a lab-scale screw mixer using the discrete element method

Numerical study of particle mixing in a lab-scale screw mixer using the discrete element method

Heat transfer rates in sheared beds of inertial particles at high Biot numbers

A coupled, multiphase heat flux boundary condition for the discrete element method

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