Simulation and design of micromixers for microfluidic devices

Passive (diffusional) mixing has been used in designing high-aspect-ratio micro-mixers for the purpose of performing Liagase Detection Reaction (LDR). The types of mixers considered are simple, cheap, and durable and can perform over a broad range of volumetric flow rates at reasonably modest pressure drops. The fluids to be mixed have a very low typical diffusion coefficient of=1.2x10-10m2/s and diffusional mixing is only effective in high-aspect-ratio micro-channels. A very modestly high aspect ratio of 6 has been considered initially because it is easily releasable using the LIGA technique. Numerical simulations of a few basic diffusional mixer configurations are going to be presented in this paper. Two variants of a Y-type mixer with contraction and several variants of a mixer employing jets in cross-flow have been simulated. The various mixers have been evaluated in terms of volumetric mixing efficiencies and maximum pressure drops. One of the mixers with jets-in-cross-flow was found to perform best.

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