A novel kinetic-based slip velocity boundary condition suitable for compressible gas flows in micro-/nanochannels

Abstract

Micro-/nanoscale gaseous flow are widely used in various industrial applications such as micro-/nanosensors, hard disk drives, etc. The purpose of the current paper is to introduce a novel slip velocity boundary condition for any flat channels gas flow that are in slip flow regime or early transition flow regime. The new boundary condition is driven from the kinetic-based modification of Navier–Stokes equation. Stress tensor in the Navier–Stokes equation is modified by using the solution of the Boltzmann equation. The present slip model shows analytically how the slip velocity boundary condition is affected not only by the axial pressure gradient but also by the compressibility of gas. The new boundary condition is verified with the main reference experimental data and numerical results of Boltzmann equation in the isothermal gas flow between two long parallel plates. The results of mass flow rate and velocity show improvement due to considering compressibility of gas.