| Abstract: |
| Sessile liquid droplets on solid surfaces are ubiquitously found in nature and engineered applications. Out of the many physical processes involved in droplet dynamics, two have been of continuous interest. The first is the moving contact line at which the evolving liquid-gas interface intersects the solid surface. The second is the evaporation at the liquid-gas interface for evaporating droplets. Coupled to both the moving contact line on the substrate and the liquid flow in the droplet, interfacial evaporation plays a critical role in controlling droplet dynamics.
Based on our earlier works on moving contact line and thin-film dynamics, we derive a continuum model for evaporating thin droplets by applying Onsager`s variational principle. This approach ensures thermodynamical consistency in describing the coupling of many dissipative processes, including viscous momentum transport, contact line motion, evaporation, and vapor diffusion. Numerical results are presented to exhibit the diffusion-limited regime and the transition-limited regime, which are distinct from each other. The coffee-ring phenomena are also numerically investigated for particle-laden droplets.
This work is supported by the Hong Kong RGC General Research Fund (No. 16302525) and the Key Project of the National Natural Science Foundation of China (No. 12131010). |
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