Zhang, YR;
Zhao, Z;
Luo, KH;
Shi, B;
(2021)
Size effects on dynamics of nanodroplets in binary head-on collisions.
Journal of Molecular Liquids
, 341
, Article 117383. 10.1016/j.molliq.2021.117383.
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Luo 2021 JML Nanodroplets accepted.pdf - Accepted Version Download (1MB) | Preview |
Abstract
Head-on collision dynamics of 10, 50 and 100 nm droplets are investigated in vacuum by molecular dynamics, involving 35,858, 4,506,410 and 36,051,466 molecules, respectively. A variety of droplet collision dynamics are observed, such as coalescence, hole formation and shattering, as a function of the Weber number. It is found for the first time that the collision and reflexive separation can occur in the nanodroplet regime when the droplet diameter reaches 100 nm but not for 10 or 50 nm droplets. The size effect in droplet collisions is studied based on the analysis of stretching factors, energy dissipation and collision outcomes for droplets of different diameters. The kinetic energy dissipation due to the atomic interactions at nanoscales is identified to significantly influence the occurrence or otherwise of reflexive separation. Through quantitative analysis of the evolution of the internal structure of the 100 nm nanodroplets collision at the Weber number of 277, it is revealed for the first time that molecules from both parent nanodroplets have penetrated the full length of the merged nanodroplet in the direction of collision, due to a combination of molecular mixing and internal currents. Consequently, all three child nanodroplets have molecules from both parent nanodroplets, contrary to the perception gained from common imaging techniques. The results show that the dynamics, outcomes and mechanisms of nanodroplet collisions have both similarities and differences compared with their micro- and macro-counterparts.
| Type: | Article |
|---|---|
| Title: | Size effects on dynamics of nanodroplets in binary head-on collisions |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.molliq.2021.117383 |
| Publisher version: | https://doi.org/10.1016/j.molliq.2021.117383 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Reflexive separation, Droplet collision, Nanoscale, Size effect, Molecular dynamics |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10134569 |
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