Lattice Boltzmann simulations of apparent slip and contact angle in hydrophobic micro-channels

TL;DR

This study uses Lattice Boltzmann simulations to explore the relationship between contact angle and slip length in hydrophobic micro-channels, proposing a formula to optimize nano-particle drag reduction.

Contribution

It introduces a novel relationship between contact angle and slip length and derives an equation for nano-particle size limits for drag reduction.

Findings

SIF and SIFS have minimal effect on contact angle-slip length relationship

Proposed relationship enables prediction of nano-particle size for drag reduction

Derived equation guides nano-particle application in microfluidic systems

Abstract

In this paper, we applied the Shan-Chen multiphase Lattice Boltzmann method to simulate two different parameters, contact angle (a static parameter) and slip length (a dynamic parameter), and we proposed a relationship between them by fitting those numerical simulation results. By changing the values of the strength of interaction between fluid particles (SIF) and the strength of interaction between fluid and solid surface (SIFS), we simulated a series of contact angles and slip lengths. Our numerical simulation results show that both SIF and SIFS have little effects on the relationship between contact angle and slip length. Using the proposed relationship between slip length and contact angle, we further derived an equation to determine the upper limit of nano-particles' diameter under which drag-reduction can be achieved when using nano-particles adsorbing method.