• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2022, Vol. 58 ›› Issue (6): 52-61.doi: 10.3901/JME.2022.06.052

• 材料科学与工程 • 上一篇    下一篇

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聚合物熔体微尺度流动过程黏度与黏性耗散的耦合作用

张嘉昆,王敏杰,李红霞,于同敏   

  1. 大连理工大学机械工程学院 大连 116024
  • 收稿日期:2021-05-22 修回日期:2021-11-20 出版日期:2022-03-20 发布日期:2022-05-19
  • 通讯作者: 王敏杰,男,1958年出生,博士,教授,博士研究生导师。主要研究方向为模具设计制造及其计算机辅助技术、聚合物材料成型技术等。E-mail:mjwang@dlut.edu.cn
  • 作者简介:张嘉昆,男,1990年出生,博士研究生。主要研究方向为聚合物材料成型技术。E-mail:zjk990@mail.dlut.edu.cn
  • 基金资助:
    国家自然科学基金资助项目(51675079)。

Coupling Effect between Viscosity and Viscous Dissipation in the Microscale Flow of Polymer Melt

ZHANG Jiakun, WANG Minjie, LI Hongxia, YU Tongmin   

  1. School of Mechanical Engineering, Dalian University of Technology, Dalian 116024
  • Received:2021-05-22 Revised:2021-11-20 Online:2022-03-20 Published:2022-05-19

摘要: 为了探究在聚合物微成型时熔体黏度与黏性耗散的耦合作用对熔体的流变特性产生的影响,采用数值计算和试验相结合的方法研究了黏度与黏性耗散之间的耦合作用。通过建立微尺度黏度和黏性耗散基于共同变量温度的耦合模型,计算并分析了不同当量直径的矩形微流道内熔体流变特性参数的变化规律,试验验证了熔体沿流动方向的温度变化。结果表明:在相同工艺参数条件下,当量直径越小,熔体黏度越小,黏性耗散作用越强,耦合作用对熔体黏度和黏性耗散的影响越强。熔体沿流动方向温度升高,不考虑耦合作用时熔体温升比考虑耦合作用时高,且偏差随当量直径的减小而增大,不同的入口速度和入口温度条件下平均温升的最大偏差分别为7.26%和7.05%。数值计算与试验结果趋势一致,对于不同的入口速度,考虑耦合作用的熔体沿流动方向的计算平均温升与试验测量值最小偏差为0.49 K;对于不同的入口温度,考虑耦合作用的熔体沿流动方向的计算平均温升与试验测量值最小偏差为0.59 K。因此,在对聚合物微成型过程中的熔体流动分析时,考虑黏度与黏性耗散之间的耦合作用,才能够更准确地反映熔体流变特性的实际变化规律。

关键词: 聚合物, 微尺度, 黏度, 黏性耗散, 熔体温度

Abstract: There exists a coupling relationship between viscosity and viscous dissipation during polymer micro molding. In order to explore the coupling effect on the rheological properties of the melt, it is studied by combining numerical simulation and experimental. A coupling model which is based on a common variable temperature is presented, and the rheological characteristic parameters of polymer melt which flows in rectangular cross section micro channels are calculated and analyzed. Then the numerical result is evaluated by the melt experiment temperature along the flow direction. The results indicate that as the equivalent diameter decreases, viscosity decreases, viscous dissipation increases, and the coupling effect on viscosity and viscous dissipation becomes stronger. The temperature of the melt increases along the flow direction. The temperature rise value of the melt is higher when the coupling is not considered than when the coupling is considered, and the deviation increases with the decrease of the equivalent diameter. The maximum deviation where the average temperature rise value is 7.26% and 7.05% respectively for different inlet velocities and different inlet temperatures. The numerical simulation values by considering the coupling are consistent with the experimental results. As the different inlet velocities, the minimum deviation of the average temperature rise value between the numerical simulation results with considering the coupling and the experimental results is 0.49 K. As the different inlet temperatures, the minimum deviation of the average temperature rise value between the numerical simulation results with considering the coupling and the experimental results is 0.59 K. Therefore, it can be more accurately reflect the actual change regularities of melt rheological properties with considering the coupling between viscosity and viscous dissipation, when analyzing the melt flow in the polymer micro molding process.

Key words: polymer, microscale, viscosity, viscous dissipation, melt temperature

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