Analytical and numerical study of gaseous flow in microchannel with sudden change of section (expansion / contraction)

In this paper, we study an isothermal gas flow (Argon) through a rectangular microchannel with sudden change of section (expansion / contraction). For that, we used two approaches, analytical and numerical, both based on the Navier-Stokes equations, which allows us predicting the pressure driven mass flow rate in the hydrodynamic and slip flow regimes. The analytical approach is elaborated considering the hypothesis of Stokes. The numerical approach is performed using the software Ansys/ Fluent for compressible flow. In the slip regime, the boundary conditions on the wall were added in the Ansys/Fluent software. Both the analytical and numerical mass flow rates show a good agreement in the hydrodynamic and slip flow regimes. The obtained results indicate that the diodicity (the dependence of the mass flow rate from the direction on perfusion) depends on the position of the sections’ change in the microchannel, and it is of the order of 2 in our configuration.