喷丝板结构对熔融纺丝挤出过程聚合物熔体流动特性的影响  

Effect of spinneret structure on flow characteristics of polymer melt in melt spinning extrusion process

作　　者：沈泽坤 王会 应起繁 SHEN Zekun;WANG Hui;YING Qifan(College of Environmental Science and Engineering,Donghua University,Shanghai 201620,China)

机构地区：[1]东华大学环境科学与工程学院,上海201620

出　　处：《现代纺织技术》2023年第6期80-91,共12页Advanced Textile Technology

摘　　要：熔体在喷丝板微孔内流动时的稳定性和流场分布的均匀性是后续决定纤维成型质量的关键,这对熔体挤出前后的速度差、流道内的剪切速率分布和口模段内径向速度均匀性提出了要求。利用计算流体力学技术对涤纶工业熔融纺丝中的聚合物微孔挤出过程进行了数值模拟,得到了聚酯熔体在微孔内流动过程的速度、压力和剪切速率分布,讨论了熔体挤出前后的速度差和剪切速率分布对熔体流动稳定性的影响。提出了评价口模段内熔体径向速度分布的流动非均匀系数,指出不同长径比和收敛角分别通过改变流动充分发展段长度和口模段入口处径向速度分量来影响流动非均匀性。研究发现非均匀系数随长径比的增大而减小,随收敛角的增大先减后增。综合分析结果表明,长径比为3、收敛角为74°的喷丝板最佳。At present,the preparation of highly homogeneous polyester fibers is still a great challenge.The stability of melt flow in the melt spinning process and the degree of non-uniformity of radial velocity distribution before extrusion affect the quality of subsequent spinning.In this paper,the flow process of polyester melt in microporous flow channel was studied by numerical simulation.The melt flow characteristics under different microporous structures and different inlet velocities of the spinneret were analyzed.The non-uniformity coefficient related to the melt velocity was proposed,and the influence mechanism of microporous flow channel structure parameters on the stability and uniformity of melt flow was further clarified.The spinneret structure corresponding to the optimum non-uniformity coefficient of melt flow was pointed out.With the increase ofthe inlet velocity,the variation degree of the average melt velocity before and after extrusion first decreases and then increases,and the flow is the most stable at 1 m s.The time pressure drop is more stable when the inlet velocity ranges from 0.5 m s to 1 m s,and is more conducive to the internal stress of the primary fiber.The increase of the flow velocity increases the average shear rate in the free section and strengthens the melt orientation.However,when the inlet flow velocity is 2 m s and 3 m s,the maximum shear rate in the flow passage reaches 105 orders of magnitude,and the possibility of melt fracture is higher,which is not conducive to the flow stability.The inlet velocity has little effect on the non-uniformity coefficient of melt flow when the spinneret geometry is unchanged.The study shows that the inlet velocity of 1m s should be selected.When the dielength-diameter ratio is 2 and 3,the average velocity before and after extrusion changes less,and the flow is more stable.When the length-diameter ratio is 2 and 3,the pressure drop is more conducive to the internal stress of the primary fiber.When the length-diameter ratio is 2,3,4,the average shear rat

关 键 词：喷丝板结构 熔融纺丝 非牛顿流体 数值模拟 流变学 非均匀系数 

分 类 号：TQ342.21[化学工程—化纤工业]