Molecular Dynamics simulation for PBR pebble tracking simulation via a random walk approach using Monte Carlo simulation

Lee, Kyoung O.; Holmes, Thomas W.; Calderon, Adan F.; Gardner, R.P.

doi:10.1016/j.apradiso.2011.11.043

Cited by 5 publications

(2 citation statements)

References 6 publications

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“…The sphere tracking appears to be a random walk, due to their random nature when selecting the new movement of each sphere [ 75 ]: The initial arrangement of the spheres results in a denser filling of the channel in its center, however, in the immediate vicinity of the wall there are plenty of empty spaces. The proposed shaking procedure allows us to designate new values of the x-y coordinates to each sphere which result from the movement of the spheres through these gaps, generating cavities into which they can be moved later.…”

Section: Packing Of Spheres Into a Channel Of An Irregular Shapementioning

confidence: 99%

Filling of Irregular Channels with Round Cross-Section: Modeling Aspects to Study the Properties of Porous Materials

et al. 2018

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The filling of channels in porous media with particles of a material can be interpreted in a first approximation as a packing of spheres in cylindrical recipients. Numerous studies on micro- and nanoscopic scales show that they are, as a rule, not ideal cylinders. In this paper, the channels, which have an irregular shape and a circular cross-section, as well as the packing algorithms are investigated. Five patterns of channel shapes are detected to represent any irregular porous structures. A novel heuristic packing algorithm for monosized spheres and different irregularities is proposed. It begins with an initial configuration based on an fcc unit cell and the subsequent densification of the obtained structure by shaking and gravity procedures. A verification of the algorithm was carried out for nine sinusoidal axisymmetric channels with different Dmin/Dmax ratio by MATLAB® simulations, reaching a packing fraction of at least 0.67 (for sphere diameters of 5%Dmin or less), superior to a random close packing density. The maximum packing fraction was 73.01% for a channel with a ratio of Dmin/Dmax = 0.1 and a sphere size of 5%Dmin. For sphere diameters of 50%Dmin or larger, it was possible to increase the packing factor after applying shaking and gravity movements.

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Section: Packing Of Spheres Into a Channel Of An Irregular Shapementioning

confidence: 99%

Filling of Irregular Channels with Round Cross-Section: Modeling Aspects to Study the Properties of Porous Materials

et al. 2018

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“…The dense slow or quasistatic high solid concentration granular flow found in hoppers is still poorly understood although the motion of particles has been researched from many different aspects of the flow with various theoretical techniques, for example, Beverloo's equation for predicting mass discharge rate, Janssen's differential slice force balance method for wall stress [2], Monte Carlo simulation with Langevin equation for granular flow trajectories [22] and Baxter's radiography method for observation of the density wave, etc. [17].…”

Section: Models On Granular Flow In Hoppersmentioning

confidence: 99%

A review on numerical models for granular flow inside hoppers and its applications in PBR

Tang

Zhang

Guo

2014

Journal of Nuclear Science and Technology

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Granular flow is the shearing motion of a collection of discrete solid particles which are commonly seen and widely utilized in various industrial applications. One of the essential applications of dense slow granular flow in engineering is the pebble flow in pebble-bed nuclear reactor (PBR). A number of numerical models have been established for researching the basic physical mechanisms and properties of granular flow. For the purpose of generating an appropriate model for high temperature reactor-pebblebed modules (HTR-PM) in the future, numerical models on granular flow in hoppers and some of their previous applications on PBRs are reviewed. In this paper, basic transport and contact mechanisms of granular flow are firstly introduced, then kinetic theory from gas molecules and plastic theory from metal mechanics approaches give descriptions of the macroscopic behavior of rapid flow and quasistatic flow regimes, respectively, subsequently kinematic continuum method and discrete element method (DEM) are presented to describe the bulk features of dense slow flow in hoppers. Since various kinematic models, DEM models and their modified versions for dense slow granular flow in hoppers have been experimentally verified and applied in prediction of pebble flow in PBRs, a promising model for HTR-PM is expected with further work to generate pebble flow profile in the future.

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Characteristics and influencing factors of interaction between hydrophobic surface and drag-reducing polymer: A MC and MD simulation study

Meng,

Wang,

Lyu

et al. 2023

Computational Materials Science

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Molecular Dynamics simulation for PBR pebble tracking simulation via a random walk approach using Monte Carlo simulation

Cited by 5 publications

References 6 publications

Filling of Irregular Channels with Round Cross-Section: Modeling Aspects to Study the Properties of Porous Materials

Filling of Irregular Channels with Round Cross-Section: Modeling Aspects to Study the Properties of Porous Materials

A review on numerical models for granular flow inside hoppers and its applications in PBR

Characteristics and influencing factors of interaction between hydrophobic surface and drag-reducing polymer: A MC and MD simulation study

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