scholarly journals Lattice Boltzmann modelling of liquid distribution in unsaturated granular media

2016 ◽  
Vol 80 ◽  
pp. 353-359 ◽  
Author(s):  
Vincent Richefeu ◽  
Farhang Radjai ◽  
Jean-Yves Delenne
Keyword(s):  
Lattice Boltzmann ◽  
Granular Media ◽  
Liquid Distribution

scholarly journals Waterfall Algorithm as a tool of investigation the geometrical features of granular porous media

2021 ◽  
Author(s):  
Wojciech Sobieski
Keyword(s):  
Particle Size ◽  
Porous Media ◽  
Lattice Boltzmann ◽  
Granular Media ◽  
Density Ratio ◽  
Geometrical Features ◽  
Granular Porous Media ◽  
Collision Density ◽  
Boltzmann Method ◽  
The Impact

AbstractThe paper describes the so-called Waterfall Algorithm, which may be used to calculate a set of parameters characterising the spatial structure of granular porous media, such as shift ratio, collision density ratio, consolidation ratio, path length and minimum tortuosity. The study is performed for 1800 different two-dimensional random pore structures. In each geometry, 100 individual paths are calculated. The impact of porosity and the particle size on the above-mentioned parameters is investigated. It was stated in the paper, that the minimum tortuosity calculated by the Waterfall Algorithm cannot be used directly as a representative tortuosity of pore channels in the Kozeny or the Carman meaning. However, it may be used indirect by making the assumption that a unambiguous relationship between the representative tortuosity and the minimum tortuosity exists. It was also stated, that the new parameters defined in the present study are sensitive on the porosity and the particle size and may be therefore applied as indicators of the geometry structure of granular media. The Waterfall Algorithm is compared with other methods of determining the tortuosity: A-Star Algorithm, Path Searching Algorithm, Random Walk technique, Path Tracking Method and the methodology of calculating the hydraulic tortuosity based on the Lattice Boltzmann Method. A very short calculation time is the main advantage of the Waterfall Algorithm, what meant, that it may be applied in a very large granular porous media.

scholarly journals Effective thermal conductivity in granular media with devolatilization: the Lattice Boltzmann modelling

2021 ◽  
Author(s):  
Arkadiusz Grucelski
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Lattice Boltzmann ◽  
Thermal Processing ◽  
Granular Media ◽  
Fossil Fuel ◽  
Transport Coefficients ◽  
Thermal Front ◽  
Sound Simulation ◽  
Boltzmann Method

AbstractFlow thermomechanics in reactive porous media is of importance in industry including the thermal processing of fossil fuel (coking understood as a slow pyrolysis) involving devolatilisation. On the way to provide a detailed description of the process, a multi-scale approach was chosen to estimate effective transport coefficients. For this case the Lattice Boltzmann method (LBM) was used due to its advantages to accurately model multi-physics and chemistry in a random geometry of granular media. After account for earlier studies, the paper presents description of the model with improved boundary conditions and a benchmark case. Results from meso-scale LBM calculations are presented and discussed regarding the spatial resolution and the choice of relaxation parameter along its influence on the accuracy compared with empirical formulae. Regarding the estimation of effective thermal conductivity coefficient it is shown that occurrence of devolatilization has a crucial effect by reducing heat transfer. Some quantitative results characterise the propagation of thermal front; also presented is the evolution of effective thermal conductivity. The work is a step forward towards a physically sound simulation of thermal processing of fossil fuel.

scholarly journals Liquid clustering and capillary pressure in granular media

2014 ◽  
Vol 762 ◽  
Author(s):  
Jean-Yves Delenne ◽  
Vincent Richefeu ◽  
Farhang Radjai
Keyword(s):  
Granular Material ◽  
Granular Media ◽  
Capillary Condensation ◽  
Peak Stress ◽  
Secondary Process ◽  
Coalescence Process ◽  
Liquid Distribution ◽  
Lattice Boltzmann Simulations ◽  
Liquid Clusters ◽  
Condensed Liquid

AbstractBy means of extensive lattice Boltzmann simulations, we investigate the process of growth and coalescence of liquid clusters in a granular material as the amount of liquid increases. A homogeneous grain–liquid mixture is obtained by means of capillary condensation, thus providing meaningful statistics on the liquid distribution inside the granular material. The tensile stress carried by the grains as a function of the amount of condensed liquid reveals four distinct states, with a peak stress occurring at the transition from a primary coalescence process, where the cohesive strength is carried mostly by the grains, to a secondary process governed by the increase of the liquid cluster volumes. We show that the evolution of capillary states is correctly captured by a simple model accounting for the competing effects of the Laplace pressure and grain–liquid interface.

Lattice Boltzmann modeling of liquid clusters in granular media

2014 ◽  
pp. 461-466
Author(s):  
Jean-Yves Delenne ◽  
Vincent Richefeu ◽  
Farhang Radjai
Keyword(s):  
Lattice Boltzmann ◽  
Granular Media ◽  
Liquid Clusters ◽  
Lattice Boltzmann Modeling

Role of contact couples and couple stress in the behaviour of granular media

1998 ◽  
Vol 08 (PR8) ◽  
pp. Pr8-87-Pr8-94
Author(s):  
F. Dedecker ◽  
Ph. Dubujet ◽  
B. Cambou
Keyword(s):  
Couple Stress ◽  
Granular Media
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