Implementation of an unresolved stabilised FEM–DEM model to solve immersed granular flows

Constant, Matthieu; Dubois, Frédéric; Lambrechts, Jonathan; Legat, Vincent

doi:10.1007/s40571-018-0209-4

Cited by 14 publications

(20 citation statements)

References 57 publications

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“…We use the LMGC90 open-source platform initially developed in Montpellier by Jean and Dubois [14] that implement the CD method. The software benefits today from a number of contributions such as contact detection between polyhedra [15], solver parallelization with OpenMP [16], thermal and electrical coupling e↵ects [17], coupling with fluids [18] or various type of contact interactions.…”

Section: The Contact Dynamics Methods For Granular Asteroid 21 Main Imentioning

confidence: 99%

LMGC90: a Contact Dynamics open source code for the simulation of granular asteroid with realistic regolith shapes. Application to the accretion process

et al. 2021

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Granular asteroids are naturally occurring gravitational aggregates (rubble piles) bound together by gravitational forces. For this reason, it is reasonable to use the theoretical concepts and numerical tools developed for granular media to study them. In this paper, we extend the field of applicability of the Contact Dynamic (CD) method, a class of non smooth discrete element approach, for the simulation of three dimensional granular asteroids. The CD method is particularly relevant to address the study of dense granular assemblies of a large number of particles of complex shape and broad particles size distribution, since it does not introduces numerical artefacts due to contact stiffness. We describe how the open source software LMGC90, interfaced with an external library for the calculation of self-gravity, is used to model the accretion process of spherical and irregular polyhedral particles.

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Section: The Contact Dynamics Methods For Granular Asteroid 21 Main Imentioning

confidence: 99%

LMGC90: a Contact Dynamics open source code for the simulation of granular asteroid with realistic regolith shapes. Application to the accretion process

et al. 2021

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“…The computational method we used to solve the contact reaction forces and move the grains is the same that the one presented in [12] in which we have added a friction law [30] and allowed rotation of the grains.…”

Section: Solid-phase Modelmentioning

confidence: 99%

“…Such a process based on a prediction of the free grains velocity has already been used and proved to be numerically efficient [12] when considering loose grains clusters. In the presence of fully deposed beds of grains, using an approximation of the grains free velocity leads to an underestimation of the drag force applied on the fluid.…”

Section: Fluid Solvermentioning

confidence: 99%

“…The directions of R n+1 s j •t s j and R * t are the same. A similar algorithm to the one described in [12] is used to find the reaction forces and the grains velocity respecting the above conditions. The friction constraints have been inserted in this algorithm to compute the grains angular velocity based on the tangential component of the reaction forces.…”

Section: Grains Solvermentioning

confidence: 99%

“…Fig 12. Comparison of the differential pressure signals in the injection pipe obtained numerically and experimentally for the case h g = 4.5 cm and I = 13 mL/min (Ca = 1.2 × 10 −2 , Re s = 196.3 and t = 1.125 × 10 −4 s).…”

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Simulation of air invasion in immersed granular beds with an unresolved FEM–DEM model

Constant¹,

Coppin²,

Dubois³

et al. 2020

Comp. Part. Mech.

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This paper is devoted to an unresolved model for the simulation of air invasion in immersed granular flows without interface reconstruction between the liquid and the gas. Experiments of air invading a granular bed immersed in ethanol were achieved in a Hele-Shaw cell to observe the gas invasion paths and to calibrate the numerical multiscale model. The grains movements are computed at a fine scale using the non-smooth contact dynamics method, a time-stepping method considering impenetrable grains. The fluid flow is modelled by equations averaged using the volume fraction of fluid and computed at a coarse scale with the finite element method. A phase indicator function is used to dissociate the gas and the liquid constituting the fluid and to compute the density and viscosity of the fluid at each position. It is moved using a convection equation at each time step. The fluid, solid and phase indicator function computations are validated on simple cases before being used to reproduce experiments of air invasion in immersed granular flows. The experiments are supported by simulations in two dimensions to refine the study and the understanding of the invasion dynamics at short times.

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Electrochemical Performance Enhancement of 3D Printed Electrodes Tailored for Enhanced Gas Evacuation during Alkaline Water Electrolysis

Rocha

Delmelle

Georgiadis

et al. 2022

Advanced Energy Materials

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This promising method allows not only to decarbonize the current hydrogen production but to decarbonize other industries as well since the carbon-free electrolytic hydrogen (or derivatives) can replace fossil fuels in the transport and heating sectors as well. As a consequence, the International Energy Agency estimates a 140% growth in hydrogen demand by 2030, with water electrolysis being responsible for almost 40% of the total production. [1] There are three main water electrolysis technologies. The most mature one is alkaline water electrolysis (AWE), with a market share of ≈60%, followed by proton exchange membrane water electrolysis (≈30% market share), and solid oxide water electrolysis. [1,2] Besides being the most mature method, AWE also has the lowest capital cost (€/kW) at a given power input, [3] since it uses abundant and inexpensive materials. [4] The state-of-the-art AWE cell configuration is a zero-gap assembly. In this configuration, the electrodes, in general 2D electrodes such as perforated plates, expanded metals, or meshes, are pressed against a separator with a thickness on the order of hundreds of micrometers. [5] Recently, 3D electrode geometries such as foams and felts have been used with promising results, [6] especially when a forced electrolytic flow is imposed. [7] However, due to the stochastic nature of these geometries, gas removal may not be optimal. As an example, Kou et al. observed an enhancement in gas evacuation when replacing foams with periodic 3D structures. [8] An important method to build tailored 3D periodic metallic structures is additive manufacturing using laser beam melting (LBM), also known as selective laser melting (SLM). [9] In this process, a thin layer of powder is deposited over a substrate plate or on the previously deposited layer and a laser beam melts the powder particles selectively. To avoid oxygen contamination, the process is done in a closed chamber containing an inert gas. [10] With the almost unlimited possible geometries that it allows to fabricate, it is important to find generic guidelines as to what kind of structure presents the best electrolytic performance in view of enhanced gas removal.Recently, a study of membrane distillation for desalination has successfully shown that 3D printed spacers can enhance heat and mass transfer and reduce the formation of dead zones. [11] A zero-gap cell with porous electrodes is a promising configuration for alkaline water electrolysis. However, gas evacuation becomes a challenge in that case, as bubbles can get trapped within the electrode's 3D structure. This work considers a number of 3D printed electrode geometries with so-called triply periodic minimal surfaces (TPMS). The latter is a mathematically defined structure that repeats itself in three dimensions with zero mean curvature, and can therefore be expected to be particularly well-suited to enhance gas evacuation. Another advantage as compared to other state-of-the-art 3D electrodes like foams or felts lies in the fact that their porosity, which dete...

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Implementation of an unresolved stabilised FEM–DEM model to solve immersed granular flows

Cited by 14 publications

References 57 publications

LMGC90: a Contact Dynamics open source code for the simulation of granular asteroid with realistic regolith shapes. Application to the accretion process

LMGC90: a Contact Dynamics open source code for the simulation of granular asteroid with realistic regolith shapes. Application to the accretion process

Simulation of air invasion in immersed granular beds with an unresolved FEM–DEM model

Electrochemical Performance Enhancement of 3D Printed Electrodes Tailored for Enhanced Gas Evacuation during Alkaline Water Electrolysis

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