A quasi-continuum hydrodynamic model for slit shaped nanochannel flow

Area of Science:

• Fluid dynamics
• Nanoscale transport phenomena
• Computational physics

Background:

• Understanding fluid behavior in nanochannels is crucial for microfluidics and materials science.
• Existing models often struggle to capture the complex interplay of fluid layering and wall interactions at the nanoscale.

Purpose of the Study:

• To develop a quasi-continuum hydrodynamic model for isothermal transport of Lennard-Jones fluid in slit nanochannels.
• To independently calculate slip and viscous contributions to fluid flow.
• To validate the model against non-equilibrium molecular dynamics simulations.

Main Methods:

• Utilized an empirical-potential based quasi-continuum theory to compute fluid density profiles.
• Employed density-dependent viscosity correlations to determine viscosity profiles within nanopores.
• Implemented a static Langevin friction model for slip boundary conditions, informed by molecular dynamics simulations.
• Investigated the impact of corrugated surfaces on wall-fluid friction.

Main Results:

• The model successfully captures the significant role of fluid layering near interfaces on apparent viscosity.
• Viscosity profiles were computed using established correlations for density-dependent viscosity.
• Slip boundary conditions were defined using a friction model dependent on wall-fluid force fluctuations.
• The proposed hydrodynamic model demonstrated good agreement with velocity profiles from non-equilibrium molecular dynamics simulations for gravity-driven flow.

Conclusions:

• The quasi-continuum hydrodynamic model provides an accurate and efficient method for simulating fluid transport in nanochannels.
• The model highlights the importance of fluid layering and wall-fluid interactions in determining flow behavior.
• This approach offers a valuable tool for designing and optimizing nanoscale devices.