Non-Continuum Effects in Micro-Channel Turbulent Gas Flow

Abstract

Motivation of this work has its origin in the boundary layer control for aeronautics and turbomachinery. For that purpose boundary layer can be modified by perforated plates with holes (small channels) of specific sizes. The questions which rise in such configuration are related to the existence of optimal size of the holes (channels) and how micro-scale effects influence behavior of the global flow. This paper concentrates on the issue of the micro-scale channel effects. It is shown, that mass flow rate is influenced by slip effects and also by global behavior of the flow. Hence, these two phenomena are balanced and the micro-channel configuration is in most cases less efficient for boundary layer control than adequate macrochannel setup. Therefore it is proved that for specific condition an optimal hole (channel) size configuration exists. The numerical investigation presented here has shown various interesting micro-scale effects for laminar and turbulent micro-channel flow, which can improve understanding of gas flow behavior in micro-channels.