间断副螺棱强化螺杆螺槽内混合行为表征

Characterization of Enhancement of Mixing Performance in the Screw-Channel by Intermittent Baffles

通过在螺杆螺槽内插入周期性间断结构副螺棱,建立新型螺杆计量段螺槽展开简化模型。借助动力学软件Ployflow,对聚合物在新型螺杆及普通螺杆螺槽内的流动情况进行模拟仿真,对比分析其流动混合效果,同时进行低密度聚乙烯(LDPE)/nano-CaCO3的共混挤出试验验证。结果表明,副螺棱周期性的扰动可触发混沌混合,提高聚合物流体的分散准数,延长粒子在螺槽中的停留时间分布,同时试验挤出物脆断面的微观结构也显示新型螺杆具有更好的混合效果。

The simplified model for unwound screw channel of the novel type single-screw, which was inserted spatially periodic intermittent baffles into the channel, was built.With the help of dynamics software Polyflow, the flow performances of polymer melt in such a new type of channel and conventional single-screw channel were simulated, and the comparative studies were performed on the mixing properties among them.Finally, the low density polyethylene (LDPE)/nano-CaCO3extrusion experiment was carried out to confirm the truth of the numerical simulation results.The results show that compared with traditional single-screw, the periodic perturbation of intermittent baffles can induce chaotic mixing, which not only broadens the residence time distribution of particles, but also heightens their mixing index.Simultaneously the microstructure of extradite brittle fracture face presented that the more efficient mixing was provided by new screw.