Enhanced flow of core-softened fluids through narrow nanotubes

Area of Science:

• Fluid dynamics
• Nanotechnology
• Computational physics

Background:

• Confined fluids exhibit unique behaviors distinct from bulk systems.
• Anomalous fluids, characterized by non-linear responses, present complex flow dynamics.
• Nanotube confinement significantly alters fluid properties and transport phenomena.

Purpose of the Study:

• To investigate the mass flux of anomalous fluids flowing through rigid nanotubes.
• To understand the impact of nanotube radius on fluid flow behavior.
• To elucidate the microscopic origins of observed flow transitions.

Main Methods:

• Non-equilibrium molecular dynamic (NEMD) simulations were employed.
• The study utilized a core-softened potential to model anomalous fluid behavior.
• System parameters, including nanotube radius and temperature, were systematically varied.

Main Results:

• An anomalous increase in mass flux was observed for smaller nanotube radii.
• A transition from single-file to ordered fluid flow was identified with increasing radius.
• A second flow transition, marked by a local minimum in mass flux, occurred at larger radii and low temperatures, attributed to double-layer formation.

Conclusions:

• Nanotube radius critically influences anomalous fluid flow, inducing distinct flow regimes.
• The core-softened potential's length scales govern the observed mass flux minima.
• Microscopic particle arrangements, such as double-layer formation, dictate complex nano-fluidic behaviors.