Hassas frezeleme mikroakıskanlar sıvı sistemleri için mikro karıştırıcı tasarımı

Mixing in microfluidic systems is a challenging problem since the flow is almost always laminar hence the transport of species depends only on diffusion. In this thesis, a passive micromixer is designed for mixing two miscible liquids in a micro channel. The mixer utilizes series of throttles, which reduce the diffusion length, placed along the mixing channel. Although there are many fabrication techniques to manufacture microfluidics, the throttles constituting the micromixer are specially designed to be fabricated by micromilling. Here, micromilling is particularly chosen because of its flexibility and productivity compared to other microfluidic fabrication methods. For design purposes, firstly the parameters affecting the mixing performance are determined. These parameters are defined as the Reynolds number (Re), non-dimensional throttle size and the number of throttles. Then, micromixers are simulated using computational fluid dynamics tools available in COMSOL Multiphysics at different parameter levels. As a result, it is found that micromixers with 15 to 20 throttles can achieve a mixing efficiency greater than 80% in very low Re flows. After optimizing the design, the micromixer is improved by shifting the throttles off the axis of the mixing channel. It is seen that the improvement increases the mixing efficiency to 84%.