Study on the Mixing Flow Field and Effect in Eccentrically Stirred Tank with Double Impellers
1. School of Mechanical Engineering, Shanghai Institute of Technology, Shanghai 201418, China;
2. School of Mechanical and Power Engineering of NJUT, Nanjing 211800, China
Abstract：In the production process, polystyrene particles are required to be suspended and mixed evenly in the liquid styrene, and the solid phase concentration should also be uniform without solid deposited in the bottom. In order to achieve the desired mixing effect, the influence of eccentricity and speed on the mixing effect was studied. In this paper, the baffle-free reactor and the double-layer 6-turn open turbo agitator equipped with the elliptical head in the bottom was taken as the research object. The stirring flow field and the polystyrene particles - styrene solid - liquid stirring were numerically simulated by Fluent software. The effects of different eccentricity and rotational speed on the agglomeration flow pattern and the concentration distribution of polystyrene particles and energy consumption were simulated. The stirring flow field of water was verified by particle image velocity (PIV) experiment. The results showed that the eccentric stirring can increase the velocity of the fluid, and the stirring dead zone below the blade was effectively improved. The increase of eccentricity led to the increasing deviation of velocity on both sides and the uneven distribution of energy. The concentration distribution of polystyrene particles by eccentric agitation was more uniform than that by symmetry mixing, which can improve the suspension effect of the particles in the styrene; In the case of the same stirring effect, the power consumption with an eccentricity of 0.15 was 85% of the mixing; The optimum eccentricity and the optimum rotational speed of the solid-liquid mixing were 0.15 and 95r/min, respectively. At this time, the solid-liquid mixing effect appeared to be the best, the solid-phase concentration distribution was the most uniform and the power consumption was relatively small.
Zhang Huimin1,Hu Shouming1,Kong Xiangzheng2. Study on the Mixing Flow Field and Effect in Eccentrically Stirred Tank with Double Impellers[J]. 化学反应工程与工艺, 2017, 33(1): 49-54.
