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dc.contributor.authorZhu, Guangpu
dc.contributor.authorKou, Jisheng
dc.contributor.authorYao, Bowen
dc.contributor.authorWu, Yu Shu
dc.contributor.authorYao, Jun
dc.contributor.authorSun, Shuyu
dc.date.accessioned2019-10-16T07:09:32Z
dc.date.available2019-10-16T07:09:32Z
dc.date.issued2019-09-27
dc.identifier.citationZhu, G., Kou, J., Yao, B., Wu, Y., Yao, J., & Sun, S. (2019). Thermodynamically consistent modelling of two-phase flows with moving contact line and soluble surfactants. Journal of Fluid Mechanics, 879, 327–359. doi:10.1017/jfm.2019.664
dc.identifier.doi10.1017/jfm.2019.664
dc.identifier.urihttp://hdl.handle.net/10754/658635
dc.description.abstractDroplet dynamics on a solid substrate is significantly influenced by surfactants. It remains a challenging task to model and simulate the moving contact line dynamics with soluble surfactants. In this work, we present a derivation of the phase-field moving contact line model with soluble surfactants through the first law of thermodynamics, associated thermodynamic relations and the Onsager variational principle. The derived thermodynamically consistent model consists of two Cahn-Hilliard type of equations governing the evolution of interface and surfactant concentration, the incompressible Navier-Stokes equations and the generalized Navier boundary condition for the moving contact line. With chemical potentials derived from the free energy functional, we analytically obtain certain equilibrium properties of surfactant adsorption, including equilibrium profiles for phase-field variables, the Langmuir isotherm and the equilibrium equation of state. A classical droplet spread case is used to numerically validate the moving contact line model and equilibrium properties of surfactant adsorption. The influence of surfactants on the contact line dynamics observed in our simulations is consistent with the results obtained using sharp interface models. Using the proposed model, we investigate the droplet dynamics with soluble surfactants on a chemically patterned surface. It is observed that droplets will form three typical flow states as a result of different surfactant bulk concentrations and defect strengths, specifically the coalescence mode, the non-coalescence mode and the detachment mode. In addition, a phase diagram for the three flow states is presented. Finally, we study the unbalanced Young stress acting on triple-phase contact points. The unbalanced Young stress could be a driving or resistance force, which is determined by the critical defect strength.
dc.description.sponsorshipNatural Science Foundation of China (51804325, 51674280 and 51774317)
dc.publisherCambridge University Press (CUP)
dc.relation.urlhttps://www.cambridge.org/core/product/identifier/S0022112019006645/type/journal_article
dc.rightsArchived with thanks to Journal of Fluid Mechanics
dc.subjectcontact lines
dc.subjectNavier–Stokes equations
dc.subjectmultiphase flow
dc.titleThermodynamically consistent modelling of two-phase flows with moving contact line and soluble surfactants
dc.typeArticle
dc.contributor.departmentComputational Transport Phenomena Lab
dc.contributor.departmentEarth Science and Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalJournal of Fluid Mechanics
dc.rights.embargodate2019-07-01
dc.eprint.versionPost-print
dc.contributor.institutionResearch Center of Multiphase Flow in Porous Media, School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China
dc.contributor.institutionSchool of Civil Engineering, Shaoxing University, Shaoxing 312000, Zhejiang, China
dc.contributor.institutionSchool of Mathematics and Statistics, Hubei Engineering University, Xiaogan 432000, Hubei, China
dc.contributor.institutionDepartment of Petroleum Engineering, Colorado School of Mines, 1600 Arapahoe Street, Golden, CO 80401, USA
kaust.personSun, Shuyu
refterms.dateFOA2019-10-17T13:21:55Z
dc.date.published-online2019-09-27
dc.date.published-print2019-11-25


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