Mass Flow Rate Measurements in a MicroChannel: from Hydrodynamic to Free Molecular Regime

Mass flow rate measurements in a single silicon micro channel were carried out for various gases in isothermal steady flows. The results obtained, from hydrodynamic to near free molecular regime by using a powerful experimental platform, allowed us to deduce interesting information, notably about the reflection/accommodation process at the wall. In the 0–0.3 Knudsen range, a continuum approximated analytic approach was derived from NS equations, associated to first or second order slip boundary conditions. Identifying the experimental mass flow rate curves to the theoretical ones the TMAC of various gases were extracted. Over all the Knudsen range [0–50] the experimental results were compared with theoretical values calculated from kinetic approaches: using variable TMAC values as fitting parameter, the theoretical curves were fitted to the experimental ones. Whatever the Knudsen range and the theoretical approach, the TMAC values are found decreasing when the molecular weights of the gas considered incre...