A stable algorithm for calculating phase equilibria with capillarity at specified moles, volume and temperature using a dynamic model
Name:
1-s2.0-S0378381217303564-main.pdf
Size:
922.7Kb
Format:
PDF
Description:
Accepted Manuscript
Type
ArticleAuthors
Kou, Jisheng
Sun, Shuyu

KAUST Department
Computational Transport Phenomena LabEarth Science and Engineering Program
Physical Science and Engineering (PSE) Division
Date
2017-09-30Permanent link to this record
http://hdl.handle.net/10754/625527
Metadata
Show full item recordAbstract
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.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.Sponsors
The authors would like to thank the anonymous reviewers for their constructive suggestions and comments to improve the original version of this paper.Publisher
Elsevier BVJournal
Fluid Phase EquilibriaAdditional Links
http://www.sciencedirect.com/science/article/pii/S0378381217303564ae974a485f413a2113503eed53cd6c53
10.1016/j.fluid.2017.09.018