Simulation of the Passive Separation of Miscible Fluid Mixtures in Two-Dimensional Micro-Channels with Uneven Wetting Conditions

This work focuses on passive separation of miscible mixtures through the surface forces in microchannels. Two fluids of physical properties imitating those of water and ethanol are investigated using the multi-range multi-components Shan-Chen Lattice Boltzmann Method (LBM) for a 2D channel. The variations of the fluid-fluid and fluid-solid interaction coefficients of both fluids, the relaxation times, and the spacing between the walls are examined under static conditions. The uneven interactions are considered with static as well as flow conditions. Because the surface forces are of intermolecular nature, their spacial range is short and did not exceed \(30 nm\) in our study. Therefore, we added solid posts distributed in patterns. The addition of these features enhanced the density jumps significantly between the upper and lower halves of the channel.