Droplet coalescence by molecular dynamics and phase-field modeling
| Autor: | Matthias Heinen, Marco Hoffmann, Felix Diewald, Steffen Seckler, Kai Langenbach, Jadran Vrabec |
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| Přispěvatelé: | Publica |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: |
Fluid Flow and Transfer Processes
thermodynamic functions thermodynamic properties drop coalescence equations of state Mechanical Engineering Computational Mechanics mathematical modeling computational fluid dynamics Condensed Matter Physics 530 Physik cryosphere molecular dynamics Physics::Fluid Dynamics computational methods Mechanics of Materials viscosity ddc:530 |
| Popis: | This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Heinen, M., Hoffmann, M., Diewald, F., Seckler, S., Langenbach, K., & Vrabec, J. (2022). Droplet coalescence by molecular dynamics and phase-field modeling. In Physics of Fluids (Vol. 34, Issue 4, p. 042006). AIP Publishing, and may be found at https://doi.org/10.1063/5.0086131. Coalescence of argon droplets with a radius of 25, 50, and 100 nm is studied with computational methods. Molecular dynamics (MD) simulations are carried out to generate reference data. Moreover, a phase-field model resting on a Helmholtz energy equation of state is devised and evaluated by computational fluid dynamics (CFD) simulations. Exactly the same scenarios in terms of geometry, fluid, and state are considered with these approaches. The MD and CFD simulation results show an excellent agreement over the entire coalescence process, including the decay of the inertia-induced oscillation of the merged droplet. Theoretical knowledge about the asymptotic behavior of coalescence process regimes is confirmed. All considered scenarios cross from the inertially limited viscous regime over to the inertial regime because of the low shear viscosity of argon. The particularly rapid dynamics during the initial stages of the coalescence process in the thermal regime is also captured by the phase-field model, where a closer look at the liquid density reveals that metastable states associated with negative pressure are attained in the emerging liquid bridge between the coalescing droplets. This demonstrates that this model is even capable of adequately handling the onset of coalescence. To speed up CFD simulations, the phase-field model is transferred to coarser grids through an interface widening approach that retains the thermodynamic properties including the surface tension. |
| Databáze: | OpenAIRE |
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