Friction factor calculation by molecular-continuum hybrid approach for flow through superhydrophobic nanochannels

Abstract

Molecular-continuum hybrid method has been employed to reduce the computational cost and present the Darcy-Weisbach friction factor correlation of water flow through the nanochannels. In this study, the surface of nanochannel walls was modified with different patterns of nanocavity to achieve the superhydrophobic surfaces. Two patterns of longitudinal and transversal nanoridge with low relative module width were considered and the results are reported for various pillar surface fractions, Reynolds numbers, and relative module width. Using all-atom molecular dynamics (MD) simulations, the correlation for the Darcy-Weisbach friction factor of water flow through the nanochannels including superhydrophobic surfaces with low relative module widths was developed. The computational time required to employ full MD simulation was compared with that of employing the hybrid method, indicating that the proposed hybrid approach is an order of magnitude more efficient than the common MD approach. Due to the combined nature of the atomistic scale and the macroscale of the continuous section, the presented approach provides the possibility of investigating the fluid behavior in large-scale nanostructured channels in various applications including nanoelectromechanical systems (NEMS) and microelectromechanical systems (MEMS).