High Knudsen number fluid flow at near-standard temperature and pressure conditions using precision nanochannels

Abstract

Gas flows over a wide range of Knudsen numbers (~0.5–10) are studied using silicon nanochannel arrays with slit-shaped pores. The pore sizes of the silicon nanochannel arrays range from micrometer to sub-10-nm scales. The flows are generated under conditions of room temperature and near-atmospheric pressure (~22°C and ~101–115 kPa) and span the continuum flow, continuum-slip flow, transition flow and free-molecular flow regimes. The measured flow rates of helium, argon and carbon dioxide are in good agreement with a theoretical model (Unified Slip Model) proposed by Beskok and Karniadakis (Nanoscale Microscale Thermophys Eng 3:43–77, 1999).