The Effect of Wall Shear Stress and Viscous Heating on Nanoscale Flow

Abstract

The effect of wall shear stress and viscous heating on nano scale flow properties and boundary conditions is presented. Molecular dynamics (MD) simulations is implemented to handle nano scale force-driven Poiseuille flow bounded by two parallel planner plates with liquid Argon subjected to wide range of wall shear stress. The excessive generated viscous heating is removed via adaptive thermal interacting wall model leading to nearly constant mean fluid temperature. The predicted results showed the classification of controlled and uncontrolled temperature flow mode (CTFM, UTFM) related to the capability of adjusting mean fluid temperature up to wall shear stress limit (WSSL). The relevant change of temperature profile and depletion layer thickness that depend on the applied wall shear stress is noticeable. It is clear that the change of depletion layer thickness influences the effective channel height and the average density. It is noticed the implementation of density and temperature on the change of fluid pressure in both CTFM and UTFM. Owing to the significant increase in pressure and temperature beyond WSSL, a supercritical fluid state is noticeable. The slip length and the fluid inhomogeneity are reported to be strongly dependent on the applied wall shear stress.

Keywords

• molecular dynamics simulations
• viscous heating
• force-driven liquid argon flow
• fluid inhomogeneity
• slip flow
• stick flow
• slip length