8 - Modelling fluid flow in nanotubes
Published online by Cambridge University Press: 29 September 2009
Summary
Fluid flow through nanoscopic structures, such as carbon nanotubes, is very different from the corresponding flow through microscopic and macroscopic structures. For example, the flow of fluids through nanomachines is expected to be fundamentally different from the flow through large-scale machines since, for the latter flow, the atomistic degrees of freedom of the fluids can be safely ignored, and the flow in such structures can be characterised by viscosity, density and other bulk properties. Furthermore, for flows through large-scale systems, the no-slip boundary condition is often implemented, according to which the fluid velocity is negligibly small at the fluid–wall boundary.
Reducing the length scales immediately introduces new phenomena, such as diffusion, into the physics of the problem, in addition to the fact that at nanoscopic scales the motion of both the walls and the fluid, and their mutual interaction, must be taken into account. It is interesting to note that the movement of the walls is strongly size-dependent. On the conceptual front, the use of standard classical concepts, such as pressure and viscosity, might also be ambiguous at nanoscopic scales, since, for example, the surface area of a nanostructure, such as a nanotube, may not be amenable to a precise definition.
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- Information
- Computational Physics of Carbon Nanotubes , pp. 211 - 224Publisher: Cambridge University PressPrint publication year: 2007