Filtration model for polydisperse aerosols in gas‐solid flow using granule‐resolved direct numerical simulation

Kolakaluri, Ravi; Murphy, Eric; Subramaniam, Shankar; Brown, Robert C.; Fox, Rodney O.

doi:10.1002/aic.14901

Cited by 7 publications

(3 citation statements)

References 17 publications

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“…One of the many examples is the fate of pollutants in groundwater systems, an emerging environmental issue countered with interventions based on the injection of nanoscopic zero-valent iron particles, to cite a particular successful application [1,2,3]. More in general, the study of solute deposition is of central importance in filtration processes to enhance air and water quality [4], chromatographic systems, catalytic cells and packed bed reactors [5,6,7], enhanced oil recovery techniques [8], and even drug delivery studies [9,10]: all these processes rely on a detailed understanding of how transported solutes/particles flow through a porous matrix and interact with it. Thus in this section we will give a brief overview of the theoretical framework typically used in the study of mass transport and particle deposition in porous media, and, in particular, the classical colloid filtration theory.…”

Section: Introductionmentioning

confidence: 99%

A robust upscaling of the effective particle deposition rate in porous media

Boccardo

Crevacore

Sethi

et al. 2018

Journal of Contaminant Hydrology

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In the upscaling from pore-to continuum (Darcy) scale, reaction and deposition phenomena at the solid-liquid interface of a porous medium have to be represented by macroscopic reaction source terms. The effective rates can be computed, in the case of periodic media, from three-dimensional microscopic simulations of the periodic cell. Several computational and semi-analytical models have been studied in the field of colloid filtration to describe this problem. They often rely on effective deposition rates defined by simple linear reaction ODEs, neglecting the advection-diffusion interplay, and assuming slow reactions (or large Péclet numbers). Therefore, when these rates are inserted into general macroscopic transport equations, they can lead to conceptual inconsistencies and, therefore, often qualitatively wrong results. In this work, we study the upscaling of Brownian deposition on face-centred cubic (FCC) spherical arrangements using a linear effective reaction rate, defined by volume averaging, and a macroscopic advection-diffusion-reaction equation. The case of partial deposition, defined by an attachment probability, is studied and the limit of ideal deposition is retrieved as a particular case. We make use of a particularly convenient computational setup that allows the direct computation of the asymptotic stationary value of effective rates. This allows to drastically reduce the computational domain down to the scale of the single repeating periodic unit: the savings are ever more noticeable in the case of higher Péclet numbers, when larger physical times are needed to reach the asymptotic regime, and thus, equivalently, a much larger computational domain and simulation time would be needed in a traditional setup. We show how this new definition of deposition rate is more robust and extendable to the whole range of Péclet numbers; it also is consistent with the classical heat and mass transfer literature.

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Section: Introductionmentioning

confidence: 99%

A robust upscaling of the effective particle deposition rate in porous media

Boccardo

Crevacore

Sethi

et al. 2018

Journal of Contaminant Hydrology

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“…The study of fluid flow and transport in porous media is of pivotal importance, as it finds application in a variety of fields, notably the investigation of remediation techniques for contaminated aquifers [1][2][3][4][5][6], the design of packed bed reactors and filters [7][8][9][10][11][12], enhanced oil recovery [13], and thermoradiotherapy [14,15]. Pore-scale numerical simulations can effectively be used to quantitatively assess the key processes controlling flow and transport phenomena [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Recirculation zones induce non-Fickian transport in three-dimensional periodic porous media

et al. 2016

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In this work, the influence of pore space geometry on solute transport in porous media is investigated performing computational fluid dynamics pore-scale simulations of fluid flow and solute transport. The three-dimensional periodic domains are obtained from three different pore structure configurations, namely, face-centered-cubic (fcc), body-centered-cubic (bcc), and sphere-in-cube (sic) arrangements of spherical grains. Although transport simulations are performed with media having the same grain size and the same porosity (in fcc and bcc configurations), the resulting breakthrough curves present noteworthy differences, such as enhanced tailing. The cause of such differences is ascribed to the presence of recirculation zones, even at low Reynolds numbers. Various methods to readily identify recirculation zones and quantify their magnitude using pore-scale data are proposed. The information gained from this analysis is then used to define macroscale models able to provide an appropriate description of the observed anomalous transport. A mass transfer model is applied to estimate relevant macroscale parameters (hydrodynamic dispersion above all) and their spatial variation in the medium; a functional relation describing the spatial variation of such macroscale parameters is then proposed.

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“…The process optimization for the combined hot gas desulfurization and dust removal were investigated. Murphy et al 35 and Guan et al 36 proposed a three-dimensional model based on the microscopic method to simulate the granular bed filtration process. These studies mainly focused on the collection mechanisms of single granule.…”

Section: Introductionmentioning

confidence: 99%

Filtration Performance of Coal Pyrolysis Flying Char Particles in a Granular Bed Filter

et al. 2018

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The filtration of flying char particles from coal pyrolysis vapors plays a very important role in enhancing yields and quality of pyrolysis oil. In this work, the performance of coal pyrolysis flying char particles in a granular bed filter (GBF) was studied in cold model experiments. A filtration model was developed using a macroscopic phenomenological method that describes the filtration of the GBF. The polynomial expression of the relative filter coefficient (F) and the nonlinear expression of the relative pressure drop ratio (G) were applied in the new model. The unsteady state of granular filtration was captured, demonstrating that the GBF performance could be predicted by the new model. Effects of superficial gas velocity, thickness of granular layer, and dust mass concentration on collection efficiency and pressure drop were analyzed. An excellent performance of the GBF was obtained and the total collection efficiency could reach a span between 98% and 99.9%. In the case of lower dust mass concentration, the total collection efficiency and pressure drop were slightly affected by the increasing dust mass concentration. The optimal operating conditions of the GBF were obtained: a superficial gas velocity of 0.2–0.6 m/s and a granular layer thickness of 0.07–0.11 m.

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Filtration model for polydisperse aerosols in gas‐solid flow using granule‐resolved direct numerical simulation

Cited by 7 publications

References 17 publications

A robust upscaling of the effective particle deposition rate in porous media

A robust upscaling of the effective particle deposition rate in porous media

Recirculation zones induce non-Fickian transport in three-dimensional periodic porous media

Filtration Performance of Coal Pyrolysis Flying Char Particles in a Granular Bed Filter

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