DYNAMICS OF FLUID-FLOW INSIDE CARBON NANOTUBES

The dynamics of fluid flow through nanomachines is different from in o ther systems in that the flow is granular (no continuum assumption) an d that the 'walls' move. We have performed molecular dynamics simulati ons of the flow of helium and argon inside carbon (graphite) nanotubes of several sizes. The fluid was started at some initial velocity; flu id particles were allowed to recycle axially through the tube via mini mum image boundary conditions. Argon slowed down more quickly than hel ium. In addition, the behaviour of the fluid strongly depended on the rigidity of the tube; a dynamic tube slowed down the fluid far more qu ickly than one in which the tube was held frozen. It also depended on the fluid density and tube diameter. It did not, however, depend on th e tube length, because fluid flow tended to prevent the development of strong longitudinal modes, whose behaviour is length dependent.