Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

MOLECULAR DYNAMICS STUDY ON INTERFACE FORCE BALANCE OF NANOBUBBLES

Get access (open in a dialog) DOI: 10.1615/IHTC13.p8.230
9 pages

Abstrakt

We have observed the nanobubbles on the hydrophilic and the hydrophobic surfaces in the simulation of the nanochannel flow. In this paper, the interface force balance of the nanobubbles is focused on and molecular dynamics simulations are carried out to examine the nanobubble interface structure of simple Lennard- Jones fluids. The nanobubble exists stable under the equilibrium state and the size of the nanobubble can be maintained. It is found that there are few vapor particles in the nanobubble and the internal vapor pressure of the nanobubble is much lower than that required by the Young-Laplace equation. The results are contradictory to the classical description, which is based on a hypothesis that the bubble is full of vapor atoms and thus, the force inside the bubble is in balance with that outside the bubble. Therefore, the liquid-vapor interface structure of the nanobubble is analyzed and the force balance of the equilibrium bubble, growing bubble and the shrinking bubble are investigated. We find that the intermolecular forces of radial component point to the liquid side. That is, the radial forces caused by the bulk liquid phase form a resistance to the external pressure to reach the force balance at the curved liquid-vapor interface. Compared with the steady bubble, the thickness of the curved liquid-vapor interface of the shrinking bubble varies to be thinner and thinner and disappears when the bubble vanishes. In disagreement with the prediction of the Young-Laplace equation, we suggest that the liquid-vapor interface region plays an important role on the force balance at the curved liquid-vapor interface for the nanobubble.