双转子连续混炼机混炼段拉伸作用的研究

Study on Stretching Effect in Mixing Section of Two-rotor Continuous Mixers

采用有限元分析软件Polyflow对双转子连续混炼机混炼段的三维非等温流场进行了模拟,并通过聚丙烯/聚苯乙烯混炼实验进行验证。利用扫描电子显微镜观察混炼样品的断面形貌,分析流场特性。结果表明,在混炼过程中,螺棱交汇区物料所受的拉伸作用比正向输送区和反向输送区物料受到的拉伸作用大;在同一截面上,螺棱顶部附近物料受到的拉伸作用较大,C形区物料受到的拉伸作用比较小;转子螺棱顶部形成了收敛流道,可提供高的拉伸作用。总的来看,由于转子的特殊结构,从进口到出口物料经历了反复的拉伸、断裂、重新分布过程,分散混合效果得以强化。

The 3-D non-isothermal flow field in mixing section of two-rotor continuous mixers was simulated by software Polyflow and was tested by PP/PS mixing. The fracture surface morphology of the samples was observed by scanning electron microscope （SEM） in order to study the flow field characteristics. It indicated that the stretching effects in rotor convergence zone were stronger than those in positive or negative transportation zone in mixing process; the stretching effect of material near the top area of screw edge was stronger and those in the C zone was smaller in the same cross section; the convergent channel at the top area of screw edge provided intense stretching effect. In general, because of special structure of the rotor, material was stretched, fractured, and redistributed repeatedly during the mixing process, which promoted dispersion mixing process.