Creeping Flow through Microchannels with Integrated Micro-pillars

Pressure drop through micro-pillar-integrated mini/microchannels is studied experimentally and analytically. Following our previous studies, the low aspect ratio micropillars embedded in a microchannel are modeled as a porous medium sandwiched between channel walls. The pressure drop is expressed as a function of the salient geometrical parameters such as channel dimension, diameter and spacing between the adjacent cylinders as well as their arrangement. To verify the developed model, several silicon/glass samples with and without integrated pillars are fabricated using the deep reacting ion etching (DRIE) technique. Pressure drop measurements are performed over a range of water flow rates ranging from 0.1 ml/min to 0.5 ml/min. The proposed model is successfully verified with the present experimental data. A parametric study is performed by employing the proposed model, which shows that the flow resistance has a reverse relationship with the micro-pillar diameter and the mini/microchannel porosity. In addition, staggered arrangements have a significantly lower flow resistance than squared arrays of pillars especially in dense structures.