转子结构和工艺参数对双转子连续混炼机混合性能的影响

Influence of Rotor Structure and Technological Parameters on Mixing Performance of A Two-rotor Continuous Mixer

利用POLYFLOW软件,对聚合物熔体在双转子连续混炼机混炼段的拟稳态流场进行数值模拟,采用粒子示踪分析方法对物料所经历的流场特性进行统计学分析。得到了平均剪切应力、停留时间分布、累积最大拉伸速率等参数,通过其分析了转子结构和工艺参数对双转子连续混炼机混合性能的影响。结果表明,转子转速的提高使物料所经受的剪切和拉伸作用增强;喂料速率的提高,使比剪切速率减小,物料在混炼段的停留时间变短;螺棱交汇区长度减小,则流场中的剪切作用增强;螺棱交汇区长度和螺棱包角对停留时间分布的影响不大。最后对数值模拟的结果进行试验验证,结果基本一致。

Numerical simulation was performed on polymer melt in the mixing section of a two-rotor continuous mixer using POLYFLOW software. The flow field characteristics experienced by the materials was statistically analyzed using particle tracking analysis （PTA） method. The average shear rate, resident time distribution （RTD）, and cumulative max-stretch rate distribution were obtained, which were used to describe the influences of structure of rotors and technological parameters on the mixing performance of the mixer. It was found that the shearing and stretching actions that materials subjected to increased with increasing rotor speed; the specific shear rate in unit resident time of the materials in the mixing section decreased with increasing feeding rate; the shearing action increased with decreasing length of rotor convergence section. The length of rotor convergence section and the angle of rotor had little influence on resident time distribution. The resuits of numerical simulation agreed well with the data.