Laminar fluid behavior in microchannels using micropolar fluid theory

In this paper, we describe microchannel fluid behavior using a numerical mo del based on micropolar fluid theory and experimentally verify the model us ing micromachined channels. The micropolar fluid theory augments the laws o f classical continuum mechanics by incorporating the effects of fluid molec ules on the continuum. The behavior of fluids was studied using surface mic romachined rectangular metallic pipette arrays. Each array consisted of 5 o r 7 pipettes with widths varying from 50 to 600 mu m and heights ranging fr om 20 to 30 mu m. A downstream port for static pressure measurement was use d to eliminate entrance effects. A controllable syringe pump was used to pr ovide flow while a differential pressure transducer was used to record pres sure drop. The experimental data obtained for water showed an increase in t he Darcy friction factor when compared to traditional macroscale theory, es pecially at the lower Reynolds number flows. The numerical model of the mic ropolar fluid theory predicted experimental data better than the classical Navier-Stokes theory and the model compares favorably with the currently av ailable experimental data. (C) 1999 Elsevier Science S.A. All rights reserv ed.