Lattice Boltzmann simulation of water flow through rough nanopores

Abstract

Water transport at the nanoscale is a significant phenomenon related to unconventional hydrocarbon production. This study develops a new model of the lattice Boltzmann method to simulate the nanoconfined water transport through a rough pore. The proposed model considers the interface viscosity and the slip length according to the surface wettability. Water flow simulations are conducted to analyze the flow characteristics and the transport capacity under various wettability and surface roughness conditions. Results show that the fluid velocity and pressure distributions along the flow direction are profoundly affected by the rough surface. As the contact angle increases, the transport capacity has a minor increase in the hydrophilic condition, but a significant rise in the hydrophobic state. Also, with the increase of relative surface roughness, the transport capacity for the hydrophobic rough nanopore is greatly enhanced, while for the hydrophilic pores, only a minor variation is observed. The dimensionless liquid permeability gradually decreases as the relative surface roughness increases irrespective of the wettability. However, the fractal dimension of the rough surface rarely affects both the transport ability and the dimensionless permeability. Finally, this study presents an empirical permeability estimation model for rough nanopores.