Analysis of Position and Rotation Direction of Double Stirrer on Chaotic Advection Behavior

Abstract

Turbulent mixing can damage the material molecules because of turbulence. Whereas laminar mixing raises a problem when mixing is carried out on viscous liquids. The mixing mechanism using chaotic flow affects the mixing quality. The aim of the experiment was to determine the position and direction of the double stirrer chaotic mixer. The installation of a chaotic mixer uses a cylindrical tub and two different mixers consisting of a primary mixer (Pp) and a secondary mixer (Ps). Periodically rotate the container and stirrer. The center of the vessel and primary mixer are placed at the same coordinates. For ε=4 cm (Pp to Ps distance), there are three experiments, namely: vessel rotation and directional stirrer (P2S-a), vessel rotation and opposite stirrer (P2B-a), and vessel rotation, both primary and secondary stirrers are directional variations. (P2V-a). Eccentricity 7 cm, there are also three treatments as above: one direction (P2S-b), reverse direction (P2B-b), and variation of direction (P2V-b).

The video camera recordings are processed digitally. Qualitative data show a pattern of behavior during mixing. Meanwhile, quantitative data is used to determine the level of mixing effectiveness. The results showed that the direction of rotation of the two cylinders had no effect on the effectiveness of chaotic mixing. Based on the number of initial droplets of dye, the treatment that experienced the fastest chaos was P2B-b, at n=2 and r=3.5303. The difference in the number of color droplets does not affect chaotic behavior. The highest mixing efficiency was generated by the lowest P2V-b mixing index value of 0.94. Simultaneously, the direction between the mixer and the container will provide maximum mixing efficiency. Isolated mixing areas (island) and areas of poor mixing occur because of one-way rotation and low eccentricity