Secondary slip structures in heated micro-geometries

Abstract

Design of gaseous MEMS devices is currently very limited by restrictions of the experimental visualisation techniques. Flow behaviour on such scales resultant from the geometrical confinement is significantly affected by slip phenomena where curvature of the wall and gradients of density and temperature influence flow patterns. This paper presents a numerical study of steady low Reynolds (Re≪1) and low Knudsen (Kn≪0.1) numbers in heated microchannel systems with curved walls. The flows, that will be described here, are characterised by vortex structures despite their very low Reynolds numbers. The performed investigation gives new insight to the flow behaviour for such conditions with an extensive topological study of the resultant flow structures. As an application we propose gaseous microfluidic systems, such as a flow diode. This study is unique in its application of Navier–Stokes set of equations with a secondary slip wall boundary condition formulation for non-isothermal domains.