Biroun, MH;
Li, J;
Tao, R;
Rahmati, M;
McHale, G;
Dong, L;
Jangi, M;
... Fu, Y; + view all
(2020)
Acoustic Waves for Active Reduction of Contact Time in Droplet Impact.
Physical Review Applied
, 14
(2)
, Article 024029. 10.1103/PhysRevApplied.14.024029.
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Abstract
Minimizing droplet impact contact time is critical for applications such as self-cleaning, antierosion or anti-icing. Recent studies have used the texturing of surfaces to split droplets during impact or inducing asymmetric spreading, but these require specifically designed substrates that cannot be easily reconfigured. A key challenge is to realize an effective reduction in contact time during droplet impingement on a smooth surface without texturing but with active and programmable control. Our experimental results show that surface acoustic waves (SAWs), generated at a location distant from a point of droplet impact, can be used to minimize contact time by as much as 35% without requiring a textured surface. Additionally, the ability to switch on and off the SAWs means that a reduction in droplet impact contact time on a surface can be controlled in a programmable manner. Moreover, our results show that, by applying acoustic waves, the impact regime of the droplet on the solid surface can be changed from deposition or partial rebound to complete rebound. To study the dynamics of droplet impact, we develop a numerical model for multiphase flow and simulate different droplet impingement scenarios. Numerical results reveal that the acoustic waves can be used to modify and control the internal velocity fields inside the droplet. By breaking the symmetry of the internal recirculation patterns inside the droplet, the kinetic energy recovered from interfacial energy during the retraction process is increased, and the droplet can be fully separated from the surface with a much shorter contact time. Our work opens up opportunities to use SAW devices to minimize the contact time, change the droplet impact regime, and program or control the droplet’s rebounding on smooth or planar and curved surfaces, as well as rough or textured surfaces.
| Type: | Article |
|---|---|
| Title: | Acoustic Waves for Active Reduction of Contact Time in Droplet Impact |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/PhysRevApplied.14.024029 |
| Publisher version: | https://doi.org/10.1103/PhysRevApplied.14.024029 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Science & Technology, Physical Sciences, Physics, Applied, Physics, WATER DROPLETS, ENERGY BUDGET, SURFACE, TRANSITION, FLOW |
| 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 Chemical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10137408 |
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