A local thermal non-equilibrium model for two-phase flows with phase-change in porous media

Duval, Fabien; Fichot, F.; Quintard, Michel

doi:10.1016/j.ijheatmasstransfer.2003.07.005

Cited by 84 publications

(42 citation statements)

References 60 publications

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“…Further, to test the model we consider an idealized case study where clogging occurs. The model by Bringedal et al (2016) does not allow phase change, but we mention that Duval et al (2004) upscaled decoupled two-phase flow with phase change using volume averaging.…”

Section: Clogging In Effective Non-isothermal Reactive Porous Media Fmentioning

confidence: 99%

Effective Behavior Near Clogging in Upscaled Equations for Non-isothermal Reactive Porous Media Flow

Bringedal

Kumar

2017

Transp Porous Med

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For a non-isothermal reactive flow process, effective properties such as permeability and heat conductivity change as the underlying pore structure evolves. We investigate changes of the effective properties for a two-dimensional periodic porous medium as the grain geometry changes. We consider specific grain shapes and study the evolution by solving the cell problems numerically for an upscaled model derived in Bringedal et al (2016). In particular, we focus on the limit behavior near clogging. The effective heat conductivities are compared to common porosity-weighted volume averaging approximations and we find that geometric averages perform better than arithmetic and harmonic for isotropic media, while the optimal choice for anisotropic media depends on the degree and direction of the anisotropy. An approximate analytical expression is found to perform well for the isotropic effective heat conductivity. The permeability is compared to some commonly used approaches focusing on the limiting behavior near clogging, where a fitted power law is found to behave reasonably well. The resulting macroscale equations are tested on a case where the geochemical reactions cause pore clogging and a corresponding change in the flow and transport behavior at Darcy scale. As pores clog the flow paths shift away, while heat conduction increases in regions with lower porosity.

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Section: Clogging In Effective Non-isothermal Reactive Porous Media Fmentioning

confidence: 99%

Effective Behavior Near Clogging in Upscaled Equations for Non-isothermal Reactive Porous Media Flow

Bringedal

Kumar

2017

Transp Porous Med

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“…Refs. [184,185]. However, in most fire-related studies it is assumed that the solid and gaseous phases are in thermal equilibrium due to the much smaller volumetric heat capacity of the volatiles [70][71][72].…”

Section: Convection Advection and Diffusionmentioning

confidence: 99%

Generalized pyrolysis model for combustible solids

Lautenberger

Fernandez-Pello

2009

Fire Safety Journal

303

259

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This dissertation presents the derivation, numerical implementation, and verification/validation of a generalized model that can be used to simulate the pyrolysis, gasification, and burning of a wide range of solid fuels encountered in fires. The model can be applied to noncharring and charring solids, composites, intumescent coatings, and smolder in porous media. Care is taken to make the model as general as possible, allowing the user to determine the appropriate level of complexity to include in a simulation. The model considers a user-specified number of gas phase and condensed phase species, each having its own temperature-dependent thermophysical properties.Any number of heterogeneous (gas-solid) or homogeneous (solid-solid or gas-gas) reactions can be specified. Both in-depth radiation transfer through semi-transparent media and radiation transport across pores are considered. Volume change (surface regression or swelling/intumescence) is handled by allowing the size of grid points to change as dictated by mass conservation. All volatiles generated inside the solid escape to the ambient with no resistance to mass transfer unless a pressure solver is invoked; the resultant flow of volatiles is then calculated according to Darcy's law. A gas phase 2 convective-diffusive solver can be invoked to determine the composition of the volatiles.Oxidative pyrolysis is simulated by modeling diffusion of oxygen from the ambient into the pyrolyzing solid where it may participate in reactions. Consequently, the mass flux and composition of volatiles escaping from the solid can be calculated. To aid in determining the required input parameters, the model is coupled to a genetic algorithm that can be used to estimate the required input parameters from bench-scale fire tests or thermogravimetric analysis.

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“…For geothermal systems, the temperature dependence is essential. We assume there is no phase change, but mention that Duval et al (2004) upscale two-phase flow with phase change using volume averaging. Recently, Radu et al (2013) proposed a mass conservative mixed finite element scheme for reactive transport with varying porosity for saturated/unsaturated porous media.…”

Section: Introductionmentioning

confidence: 99%

Upscaling of Non-isothermal Reactive Porous Media Flow with Changing Porosity

et al. 2015

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Upscaling of non-isothermal reactive porous media flow with changing porosityBringedal, C.; Berre, I.; Pop, I.S.; Radu, A.F. Published in: Transport in Porous Media DOI:10.1007/s11242-015-0530-9Published: 01/09/2016 Document VersionAccepted manuscript including changes made at the peer-review stage Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Link to publication• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Abstract Motivated by rock-fluid interactions occurring in a geothermal reservoir, we present a two-dimensional pore scale model of a periodic porous medium consisting of void space and grains, with fluid flow through the void space. The ions in the fluid are allowed to precipitate onto the grains, while minerals in the grains are allowed to dissolve into the fluid, and we take into account the possible change in pore geometry that these two processes cause, resulting in a problem with a free boundary at the pore scale. We include temperature dependence and possible effects of the temperature both in fluid properties and in the mineral precipitation and dissolution reactions. For the pore scale model equations, we perform a formal homogenization procedure to obtain upscaled equations. A pore scale model consisting of circular grains is presented as a special case of the porous medium.

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A local thermal non-equilibrium model for two-phase flows with phase-change in porous media

Cited by 84 publications

References 60 publications

Effective Behavior Near Clogging in Upscaled Equations for Non-isothermal Reactive Porous Media Flow

Effective Behavior Near Clogging in Upscaled Equations for Non-isothermal Reactive Porous Media Flow

Generalized pyrolysis model for combustible solids

Upscaling of Non-isothermal Reactive Porous Media Flow with Changing Porosity

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