气泡在扭转元件中的流动分散行为

Flow and Dispersion Behavior of Bubbles in Torsion Elements

螺杆作为微发泡注射成型技术的核心部件,对超临界流体在聚合物中的溶解和分散具有关键的作用。对气泡在扭转元件中的沆动分散行为进行了动态可视化试验与数值分析结果表明,扭转元件具有强化径向传质的作用,使熔体发生径向扭转翻滚,进而使溶解在塚体中的气泡在扭转元件分割槽内发生拉伸塑性变形,破碎成更小的气泡并均匀分散在熔体中。同时,扭转元件中熔体飭升温速率比螺纹元件快,瘪体内温度分布更加均匀,有利于气泡分散相的稳定。相对于螺纹元件,扭转元件的分离尺度更小,混合性能更佳,并基于就,设计了一种高效混炼的Mueell微发泡专用螺杆。

As the core component of the microcellular injection molding technology, the screw had a key influence on the dissolution and dispersion of supercritical fluid in the polymer. Dynamic visualization experiment and numerical analysis were carried out on the flow and dispersion behavior of bubbles in torsion elements. The results showed that the torsion element had the effect of strengthening the radial mass transfer, making the melt twisting and rolling in raoial direction , and then making the bubbles dissolved in the melt to generate tensile plastic deformation in the channel of torsion element and breaking into smaller bubbles and dispersing in the melt evenly. At the same time, the heating rate of the melt in the torsion element was faster than that of the screw element, so that the temperature distribution in the melt was more uniform , which was conducive to the stability of the dispersed phase of the bubble. Compared with the screw elements, the separation scale of the torsion elements was smaller and the mixing performance was better. Based on this, a kind of Mueell microcellular special screw with high efficiency mixing was designed.