On the Numerical Simulation of Rarefied Gas Flows in Micro-channels

Classical continuum methods break down for rarefied gas flows in micro-channels. Two non-continuum hydrodynamic models are investigated here: compressible Korteweg fluid-like and Bi-Velocity (Volume Diffusion) hydrodynamic models. The pressure driven rarefied gas flow in a rectangular micro-channel in the whole range of Knudsen number is numerically considered. The Korteweg model shows improved results in comparison with standard Navier–Stokes up to Knudsen number of unity. The Bi-Velocity method is found to allow a match between experiments and numerical results over the full range of Knudsen number.