dc.contributor.author Kou, Jisheng dc.contributor.author Sun, Shuyu dc.date.accessioned 2017-10-02T10:53:15Z dc.date.available 2017-10-02T10:53:15Z dc.date.issued 2017-09-30 dc.identifier.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. dc.identifier.issn 0378-3812 dc.identifier.doi 10.1016/j.fluid.2017.09.018 dc.identifier.uri http://hdl.handle.net/10754/625527 dc.description.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. dc.description.sponsorship The authors would like to thank the anonymous reviewers for their constructive suggestions and comments to improve the original version of this paper. dc.publisher Elsevier BV dc.relation.url http://www.sciencedirect.com/science/article/pii/S0378381217303564 dc.rights NOTICE: 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/ dc.subject Phase equilibria dc.subject NVT flash dc.subject Phase stability dc.subject Capillarity dc.subject Thermodynamical modeling dc.subject Convex-concave splitting dc.title A stable algorithm for calculating phase equilibria with capillarity at specified moles, volume and temperature using a dynamic model dc.type Article dc.contributor.department Computational Transport Phenomena Lab dc.contributor.department Earth Science and Engineering Program dc.contributor.department Physical Science and Engineering (PSE) Division dc.identifier.journal Fluid Phase Equilibria dc.eprint.version Post-print dc.contributor.institution School of Mathematics and Statistics, Hubei Engineering University, Xiaogan 432000, Hubei, China kaust.person Sun, Shuyu
﻿

### Files in this item

Name:
1-s2.0-S0378381217303564-main.pdf
Size:
922.7Kb
Format:
PDF
Description:
Accepted Manuscript