Pore Network Drying Model for Particle Aggregates: Assessment by X-Ray Microtomography

Wang, Yujing; Kharaghani, Abdolreza; Metzger, Thomas; Tsotsas, Evangelos

doi:10.1080/07373937.2012.713422

Cited by 37 publications

(12 citation statements)

References 30 publications

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“…These authors revealed that liquid film rings can develop in systems with heterogeneous wetting properties and limited interconnection of the solid, such as in a 2D microfluidic device (as investigated in Vorhauer et al [13] ) or 3D glass bead packings. [2,15] The specific strength of the pore scale model is also revealed in face of the nonisothermal drying experiments studied in Vorhauer et al, [12] where the pore network is simultaneously invaded by the gas-phase (as a result of evaporation) and the liquid phase (as a result of condensation). This phenomenon is also expected in a wide range of other applications, such as the simultaneous drainage and imbibition in gas diffusion layers (GDL), in fuel cells usually affected by thermal gradients.…”

Section: Introductionmentioning

confidence: 89%

“…Pore network models (PNM) are discrete pore scale models well appropriate to analyze the link between the discrete phenomena taking place at the pore scale and the macroscopic behavior at the sample scale. In drying, PNM shed light on the dependency of the macroscopically observed drying rate and overall drying time on pore structure, [1][2][3] capillary number or Bond number, [4,5] wettability, [6][7][8] and thermal gradients [9][10][11][12] which naturally develop since the evaporation of liquid is basically a nonisothermal process. Exemplarily, Metzger et al [1] revealed the impact of the presence and interconnection of macropores in drying of capillary porous media.…”

Section: Introductionmentioning

confidence: 99%

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Drying of thin porous disks from pore network simulations

2017

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Thin porous media (TPM) are porous layers that are characterized by a small thickness, usually orders of magnitude smaller than the lateral dimensions. We present pore network simulation revealing that drying of TPM is substantially different from drying of thicker porous media because of the impact of the small thickness of only a few pore layers on the liquid phase structure during drying. The small thickness limits the long-distance connectivity within the liquid clusters and thus causes the formation of smaller clusters characterized by shorter residence times. As a result of this stronger and earlier liquid phase fragmentation the drying of TPM is shown to be significantly more sensitive to the distribution of the evaporation flux at the surface. It is also shown that the drying behavior transition from thin to thick porous media is progressive. Moreover, it is discussed how an imposed temperature distribution can be used to control the evolution of the liquid cluster distribution in a TPM and thereby the evolution of the evaporation rate. KEYWORDS 3D po re netwo rk model; drying; nonisothermal; temperature gradient; thin po ro us disk

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Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Drying of thin porous disks from pore network simulations

2017

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“…Once the solid skeleton is segmented with satisfying accuracy, the next step is to construct the pore space, based on tetrahedra and Voronoi polyhedra similar to [32,23]. First, a layer of regularly spaced ghost particles is added on all surfaces.…”

Section: Image Processing and Analysismentioning

confidence: 99%

Tomographic Study of Internal Erosion of Particle Flows in Porous Media

et al. 2018

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In particle-laden flows through porous media, porosity and permeability are significantly affected by the deposition and erosion of particles. Experiments show that the permeability evolution of a porous medium with respect to a particle suspension is not smooth, but rather exhibits significant jumps followed by longer periods of continuous permeability decrease. Their origin seems to be related to internal flow path reorganization by avalanches of deposited material due to erosion inside the porous medium. We apply neutron tomography to resolve the spatio-temporal evolution of the pore space during clogging and unclogging to prove the hypothesis of flow path reorganization behind the permeability jumps. This mechanistic understanding of clogging phenomena is relevant for a number of applications from oil production to filters or suffosion as the mechanisms behind sinkhole formation.Comment: 18 pages, 9 figure

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“…With XACI, spatio‐temporal changes in pore‐scale water content can be resolved only when the pores are at the hundreds of μm – mm scale and/or the transport process leads to a large change in the saturation degree (fraction of pore volume filled in by water), e.g. from complete saturation to empty pores (Ketcham & Iturrino, ; Kohout et al ., ; Sant & Weiss, ; Pease et al ., ; Wang et al ., ). For porous materials with pore size distribution extending into the μm and sub‐μm ranges, as in the case studied in this work, it may be unfeasible to resolve the local water content changes, due to (1) the small X‐ray attenuation by water compared with the one by the porous substrate and (2) the small water volume changes at the pore‐scale.…”

Section: Introductionmentioning

confidence: 97%

Visualization of water drying in porous materials by X‐ray phase contrast imaging

Yang

Griffa

Bonnin

et al. 2016

Journal of Microscopy

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We present in this study results from X-ray tomographic microscopy with synchrotron radiation performed both in attenuation and phase contrast modes on a limestone sample during two stages of water drying. No contrast agent was used in order to increase the X-ray attenuation by water. We show that only by using the phase contrast mode it is possible to achieve enough water content change resolution to investigate the drying process at the pore-scale. We performed 3D image analysis of the time-differential phase contrast tomogram. We show by the results of such analysis that it is possible to obtain a reliable characterization of the spatial redistribution of water in the resolved pore system in agreement with what expected from the theory of drying in porous media and from measurements performed with other approaches. We thus show the potential of X-ray phase contrast imaging for pore-scale investigations of reactive water transport processes which cannot be imaged by adding a contrast agent for exploiting the standard attenuation contrast imaging mode.

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Pore Network Drying Model for Particle Aggregates: Assessment by X-Ray Microtomography

Cited by 37 publications

References 30 publications

Drying of thin porous disks from pore network simulations

Drying of thin porous disks from pore network simulations

Tomographic Study of Internal Erosion of Particle Flows in Porous Media

Visualization of water drying in porous materials by X‐ray phase contrast imaging

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