Static chaos microfluid mixers using microblock-induced alternating whirling and microchannel-induced lamination

Abstract

This thesis investigates Static chaos microfluid mixers for Micro Total Analysis Systems (μTAS). The present design uses microblock for generating whirling flow in microchannel. Using microblock-induced whirling flow, we propose static chaos microfluid mixers that make alternating whirling flow for generating complexities of fluid motion (AW-type). Additionally, we propose static chaos microfluid mixers that use both alternating whirl and lamination, which is dividing channel-induced fluid splitting (AWL-type). For the test of mixing quantities, we use pH indicator phenolphthalein-ethanol solution. Using detecting the color intensities on the specimens, we quantify the mixing quantity and measure mixing length that is axial length required for 90% mixing. In the experimental study, AW-type and AWL-type can enhance mixing in microscale. AW-type enhances mixing well in relatively high Re, such as Re=6.5,13. AWL-type enhances mixing in wide range. 0.13<Re<13 (mixing length is from 0.28cm to 0.58cm). Additionally, we measure pressure drops. In the case of AW-type and AWL-type, pressure drops at maximum flow rate condition (240㎕/min, Re=13) are less than 7kPa and 5kPa, respectively. Present AWL-type static chaos microfluid mixer shows small mixing lengths, good mixing quantities, and relatively small pressure drops, which can be supplied by typical micropumps. Therefore, for the applications of Micro Total Analysis Systems (μTAS), present work has potential advantage that can reduce total size of systems and let the performance of μTAS better.