A stable algorithm for calculating phase equilibria with capillarity at specified moles, volume and temperature using a dynamic model

Handle URI:
http://hdl.handle.net/10754/625527
Title:
A stable algorithm for calculating phase equilibria with capillarity at specified moles, volume and temperature using a dynamic model
Authors:
Kou, Jisheng ( 0000-0003-0986-5900 ) ; Sun, Shuyu ( 0000-0002-3078-864X )
Abstract:
Capillary pressure can significantly affect the phase properties and flow of liquid-gas fluids in porous media, and thus, the phase equilibrium calculation incorporating capillary pressure is crucial to simulate such problems accurately. Recently, the phase equilibrium calculation at specified moles, volume and temperature (NVT-flash) becomes an attractive issue. In this paper, capillarity is incorporated into the phase equilibrium calculation at specified moles, volume and temperature. A dynamical model for such problem is developed for the first time by using the laws of thermodynamics and Onsager's reciprocal principle. This model consists of the evolutionary equations for moles and volume, and it can characterize the evolutionary process from a non-equilibrium state to an equilibrium state in the presence of capillarity effect at specified moles, volume and temperature. The phase equilibrium equations are naturally derived. To simulate the proposed dynamical model efficiently, we adopt the convex-concave splitting of the total Helmholtz energy, and propose a thermodynamically stable numerical algorithm, which is proved to preserve the second law of thermodynamics at the discrete level. Using the thermodynamical relations, we derive a phase stability condition with capillarity effect at specified moles, volume and temperature. Moreover, we propose a stable numerical algorithm for the phase stability testing, which can provide the feasible initial conditions. The performance of the proposed methods in predicting phase properties under capillarity effect is demonstrated on various cases of pure substance and mixture systems.
KAUST Department:
Computational Transport Phenomena Lab; Physical Sciences and Engineering (PSE) Division
Citation:
Kou J, Sun S (2017) A stable algorithm for calculating phase equilibria with capillarity at specified moles, volume and temperature using a dynamic model. Fluid Phase Equilibria. Available: http://dx.doi.org/10.1016/j.fluid.2017.09.018.
Publisher:
Elsevier BV
Journal:
Fluid Phase Equilibria
Issue Date:
30-Sep-2017
DOI:
10.1016/j.fluid.2017.09.018
Type:
Article
ISSN:
0378-3812
Sponsors:
The authors would like to thank the anonymous reviewers for their constructive suggestions and comments to improve the original version of this paper.
Additional Links:
http://www.sciencedirect.com/science/article/pii/S0378381217303564
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Computational Transport Phenomena Lab

Full metadata record

DC FieldValue Language
dc.contributor.authorKou, Jishengen
dc.contributor.authorSun, Shuyuen
dc.date.accessioned2017-10-02T10:53:15Z-
dc.date.available2017-10-02T10:53:15Z-
dc.date.issued2017-09-30en
dc.identifier.citationKou J, Sun S (2017) A stable algorithm for calculating phase equilibria with capillarity at specified moles, volume and temperature using a dynamic model. Fluid Phase Equilibria. Available: http://dx.doi.org/10.1016/j.fluid.2017.09.018.en
dc.identifier.issn0378-3812en
dc.identifier.doi10.1016/j.fluid.2017.09.018en
dc.identifier.urihttp://hdl.handle.net/10754/625527-
dc.description.abstractCapillary pressure can significantly affect the phase properties and flow of liquid-gas fluids in porous media, and thus, the phase equilibrium calculation incorporating capillary pressure is crucial to simulate such problems accurately. Recently, the phase equilibrium calculation at specified moles, volume and temperature (NVT-flash) becomes an attractive issue. In this paper, capillarity is incorporated into the phase equilibrium calculation at specified moles, volume and temperature. A dynamical model for such problem is developed for the first time by using the laws of thermodynamics and Onsager's reciprocal principle. This model consists of the evolutionary equations for moles and volume, and it can characterize the evolutionary process from a non-equilibrium state to an equilibrium state in the presence of capillarity effect at specified moles, volume and temperature. The phase equilibrium equations are naturally derived. To simulate the proposed dynamical model efficiently, we adopt the convex-concave splitting of the total Helmholtz energy, and propose a thermodynamically stable numerical algorithm, which is proved to preserve the second law of thermodynamics at the discrete level. Using the thermodynamical relations, we derive a phase stability condition with capillarity effect at specified moles, volume and temperature. Moreover, we propose a stable numerical algorithm for the phase stability testing, which can provide the feasible initial conditions. The performance of the proposed methods in predicting phase properties under capillarity effect is demonstrated on various cases of pure substance and mixture systems.en
dc.description.sponsorshipThe authors would like to thank the anonymous reviewers for their constructive suggestions and comments to improve the original version of this paper.en
dc.publisherElsevier BVen
dc.relation.urlhttp://www.sciencedirect.com/science/article/pii/S0378381217303564en
dc.rightsNOTICE: this is the author’s version of a work that was accepted for publication in Fluid Phase Equilibria. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Fluid Phase Equilibria, [, , (2017-09-30)] DOI: 10.1016/j.fluid.2017.09.018 . © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/en
dc.subjectPhase equilibriaen
dc.subjectNVT flashen
dc.subjectPhase stabilityen
dc.subjectCapillarityen
dc.subjectThermodynamical modelingen
dc.subjectConvex-concave splittingen
dc.titleA stable algorithm for calculating phase equilibria with capillarity at specified moles, volume and temperature using a dynamic modelen
dc.typeArticleen
dc.contributor.departmentComputational Transport Phenomena Laben
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalFluid Phase Equilibriaen
dc.eprint.versionPost-printen
dc.contributor.institutionSchool of Mathematics and Statistics, Hubei Engineering University, Xiaogan 432000, Hubei, Chinaen
kaust.authorSun, Shuyuen
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