聚合物熔体收敛流动的可视化实验与理论研究

Visualization and Theoretical Analysis on Converging Flow of Polymer Melt

采用可视化实验技术,获得了流过楔形收敛流道的高密度聚乙烯(HDPE)熔体内着色条料的流迹图像。实验结果表明,收敛流道内HDPE熔体的流速与由本文推导的幂律流体模型预示的流速较接近。在此基础上,采用该幂律流体模型,揭示了楔形收敛流道内流速与延伸应变速率随径向位置和偏心角度的变化规律,并利用该规律对聚合物熔体的连续挤出自增强作了分析。

Trajectory images have been obtained of a colored strand in the high density polyethylene (HDPE) melt flowing through a converging wedge channel by a visualization technique. The comparison of the experimentally determined velocity profiles of HDPE melt in the converging channel with the theoretically predicted ones using the power - law model proposed in the present article showed close agreement between the two. The profiles of the velocity and extensional strain rate in the converging wedge channel have been revealed using the power - law model andanalyzed in conjunction with the self - reinforcement of polymers from flow - induced crystallization during melt extrusion.