Enhanced Micromixing of Non-Newtonian Fluids by a Novel Zigzag Punched Impeller

In this work, a novel impeller with zigzag punched blades is developed to produce impinging jet streams from face-to-face holes to enhance mixing in a 0.282 m diameter baffled stirred tank. The micromixing experiments on non-Newtonian fluids are conducted to compare among standard six straight blade turbine (DT), down-pumping pitched blade turbine (PBTD-45°) and our novel zigzag punched impeller (ZPI). Results show that at low Reynolds numbers (700 < Re < 3000), the segregation index of ZPI is the lowest. It shows that the ZPI exhibits higher micromixing performance than other two traditional ones. Moreover, the effect of geometric parameters of blade like holes size, single section length of paddle and the zigzag angle of the novel zigzag impeller on micromixing are also investigated. It is found that the ZPI with larger zigzag angle, shorter single section length and smaller holes leads to significant improvement on micromixing efficiency.