间断副螺棱结构对挤出机内混沌混合影响的数值模拟

Numerical Simulation of Effect of Intermittent Baffle Geometry on Chaotic Mixing in Single-screw Extruders

建立了混沌单螺杆挤出机计量段展开螺槽的物理模型及数学模型,根据流体符合Carreau定律,借助Ployflow软件,采用网格叠加技术,对聚合物熔体在插有间断结构副螺棱螺槽内的流动进行了数值模拟分析,从统计学的角度结合粒子示踪技术以停留时间分布、分离尺度、混合效率及累计混合指数为指标来表征螺杆的混合性能。结果表明,当副螺棱间断次数多且高度略低于螺槽高时混沌单螺杆混合性能更好。

The physical and mathematical models of the unwound screw channel of metering zone in chaos single-screw extruder were proposed.The corresponding incompressible fluid obeyed the Carreau flow model.With the help of the mesh superposition technique provided by apolymer analysis package Polyflow,the flow and mixing of polymer melt in such an extruder,which inserted a intermittent baffle into the screw channel of metering zone,were numerically simulated.Applying the particle tracking technique and statistical methods,the mixing performance was investigated and characterized in terms of different parameters such as residence time distribution,segregation scale,mixing efficiency,and mixing index.When the baffle intermitted frequently and height slightly lower than screw channel,the chaos single-screw was better for mixing.