偏心空气射流双层桨搅拌反应器流场结构的分形特征

Fractal flow structure in eccentric air jet-stirred reactor with double impeller

搅拌槽内流场分为混沌混合区和隔离区。为提高搅拌槽内流体的混合效率、降低搅拌过程的能耗,调控流场结构特征是重要的途径。结合图像处理软件,实验研究了偏心空气射流双层桨搅拌槽内空气-水体系的流场结构分形维数的变化规律。实验结果表明,流场结构分形维数受搅拌转速和空气流速的共同作用;偏心空气射流能改变流场结构分形维数,使流体混沌混合特性增强;机械搅拌转速增大,能改变射流场的拟序结构,提高气液混合效率。

Flow field in a stirred tank was divided into chaotic and isolated mixing zones.To enhance mixing efficiency and reduce energy consumption of fluid mixing,it was an alternative way to control the flow field structure.With the aid of image processing software,fractal dimension of air-water mixing system was investigated in the eccentric air-jet stirred tank with double mechanical impeller.The results showed that the fractal dimension of flow structure was affected by the mechanical agitation speed and air flow rate,and it could be controlled by eccentric jet and the chaotic mixing performance could be enhanced.Fluid mixing performance could be improved by controlling coherent structure with increased agitation speed.