Nanodrop impact onto a solid substrate is of interest for nano-scale liquid-impingement, phase-change cooling and for material deposition processes. In the present study, classical molecular dynamics (MD) simulation techniques were implemented to study the thermo-mechanical properties of the impact of nanometer scale liquid droplets upon an atomistic substrate at a temperature higher than that of the droplet. The droplets were comprised of approximately 50,000 Lennard-Jones atoms arranged in tetramer finitely extensible non-linear elastic (FENE) chain molecules forming a sphere of 8 nm radius. They were equilibrated and then projected towards a wall, where we observed the response upon collision by changes in shape, temperature, and density gradients, across a variety of impingement velocities, substrate temperatures, and wetting conditions. The baseline cases of equal substrate and nano-drop temperature were validated by comparison with previously reported results. A reaction spectrum ranging from full thermal vaporization of the drop, with respective substrate cooling, to complete kinetic disintegration upon impact and surface heating are analyzed. The variation of thermal and kinetic effects across the parametric environment is used to identify those regimes that optimize heat transfer from the surface, as well as those that best facilitate material deposition processes.
- Fluids Engineering Division
Molecular Dynamics Simulations of Thermo-Mechanical Effects in Nanodrop Impact
Finkbeiner, J, Watkins, C, & Koplik, J. "Molecular Dynamics Simulations of Thermo-Mechanical Effects in Nanodrop Impact." Proceedings of the ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. Volume 1A, Symposia: Advances in Fluids Engineering Education; Turbomachinery Flow Predictions and Optimization; Applications in CFD; Bio-Inspired Fluid Mechanics; Droplet-Surface Interactions; CFD Verification and Validation; Development and Applications of Immersed Boundary Methods; DNS, LES, and Hybrid RANS/LES Methods. Chicago, Illinois, USA. August 3–7, 2014. V01AT05A004. ASME. https://doi.org/10.1115/FEDSM2014-21371
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