2 SIMPLE MICROMIXERS BASED ON SILICON

This paper reports modelling, fabrication and testing of two micromixe rs, The principle of mixing used for the devices was diffusion because of the small value of the Reynolds number in microcapillaries. The fi rst mixer separates the main flow into partial flows, which are latera lly alternated in order to increase the boundary surface between the l iquids. The second mixer superposes two fluids by injection of one liq uid into the other. The fabrication technology is based on etching of silicon and anodically bonding with Pyrex glass. The performance of th e mixers has been verified by mixing phenolphthalein solution and ammo nia dissolved in water. Reasonable mixing was achieved at pressures of around 4 kPa (lateral mixing) and 7 kPa (vertical mixing) with flow r ates of approximately 1 mu l min(-1). The measurements were compared w ith diffusive mixing simulations with a CFD simulator and agreement of both was observed.