NUMERICAL STUDY ON KOCH FRACTAL BAFFLE MICROMIXER

This paper is mainly to study the application of Koch fractal baffle to passive micromixers. It can be determined that the mixing efficiency of secondary Koch fractal baffle (SKFB) micromixer is better than that of primary Koch fractal baffle (PKFB). We compare and analyze the mixing efficiency when the angle between the baffle and the microchannel is 15 degrees, 30 degrees and 45 degrees with the height 100 mu m. With the changing of the angle, it contributes to enhance the chaotic convection of the micromixer. Especially at the angle of 30 degrees, the vortex caused by the Koch fractal baffle structure is more obvious, the mixing efficiency of micromixer is more than 95% at Re = 0.05 and 100. When the height of Koch fractal baffle is 50, 75 and 100 mu m, the mixing efficiency of the micromixer gradually increases. The whirling and spiral phenomenon of the streamlines increases the chaotic convection and promotes the improvement of the mixing efficiency. In the direction of microchannel, nine sections which have a significant effect on the mixing efficiency are investigated. The encircling and split phenomenon affected by the chaotic convection is shown in nine sections at Re = 0.05, 10 and 100.