Evaporation driven by conductive heat transport

Abstract

Molecular dynamics simulations are conducted to investigate the evaporation of the truncated ($2.5\sigma$) and shifted Lennard–Jones fluid into vacuum. Evaporation is maintained under stationary conditions, while the bulk liquid temperature and the thermal driving force gradient are varied over wide ranges. It is found that the particle flux and the energy flux solely depend on the interface temperature. Both of these quantities are correlated to estimate their values for macroscopically large systems. The latter is analysed by a hydrodynamic energy balance, considering conductive heat transport by Fourier's law. Following the Hertz–Knudsen approach, the evaporation coefficient is determined and found to be in good agreement with literature data based on the kinetic equation for fluids and molecular dynamics.

GRAPHICAL ABSTRACT

Keywords:

• Evaporation
• evaporation coefficient
• heat transport
• molecular dynamics
• Lennard–Jones fluid

Acknowledgments

The work was supported by the German Research Foundation (DFG) through SFB-TRR 75, Project number 84292822 – ‘Droplet Dynamics under Extreme Ambient Conditions’ and the Federal Ministry of Education and Research (BMBF) under the grant 01IH16008 ‘TaLPas: Task-basierte Lastverteilung und Auto-Tuning in der Partikelsimulation’. The simulations were performed on the national supercomputer Cray XC40 (Hazel Hen) at the High Performance Computing Center Stuttgart (HLRS) as well as on the cluster Cray CS500 (Noctua) at the Paderborn Center for Parallel Computing (PC${}^2$) and the supercomputer SuperMUC-NG at the Leibniz Supercomputing Centre Garching (LRZ). We thank S. Jöns for providing assistance with the integration of the employed LJTS2.5 equation of state into our post-processing procedure.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Deutsche Forschungsgemeinschaft [grant number 84292822].