Mesoscopic method to study water flow in nanochannels with different wettability.

Area of Science:

• Fluid dynamics
• Nanoscale science
• Computational physics

Background:

• Molecular dynamics (MD) simulations are standard for nanoscale water flow but computationally intensive for complex geometries.
• Conventional continuum equations fail at the nanoscale due to significant fluid-surface interactions.

Purpose of the Study:

• To develop a computationally efficient mesoscopic method for modeling water flow in nanochannels.
• To incorporate molecular interactions and surface wettability into nanoscale flow simulations.

Main Methods:

• A novel mesoscopic lattice Boltzmann method (LBM) was developed to capture non-ideal water flow behaviors.
• Molecular interactions between water and channel walls were integrated into LBM, translating to slippage effects.
• The LBM model was validated against 47 published cases of infinite-length nanochannel flow and 44 finite-length cases.

Main Results:

• The LBM demonstrated high accuracy, comparable to MD simulations, for nanochannel water flow.
• Flow rates predicted by LBM were up to seven orders of magnitude higher than classical Hagen-Poiseuille flow.
• The model successfully accounted for entrance and exit effects in finite-length nanochannels.

Conclusions:

• The proposed LBM offers a computationally efficient and accurate alternative to MD for nanoscale fluid dynamics.
• This method has potential applications for simulating water flow in complex nanostructures like membranes and shale.
• The LBM provides a robust tool for understanding fluid behavior at the nanoscale, considering molecular interactions and surface properties.