收缩微流道中高分子溶液流动行为的数值模拟与实验

Numerical Simulation and Experiment on Flow Behavior of Polymer Solution in Contraction Microchannel

利用实验与数值模拟相结合的方法,研究了质量分数为0.3%的聚氧化乙烯(PEO)水溶液在4:1收缩微流道中的流动行为。进行数值模拟时,借助有限元分析软件Polyflow,采用指数型Phan-Thien-Tanner(PTT)本构模型,分别对PEO水溶液在Weissenberg数分别为5.9,7.2,8.1和9.8时和在4:1直角收缩微流道、4:1圆弧过渡收缩微流道中的流变行为进行了模拟分析。结果显示,实验结果与数值模拟结果的吻合较好,表明PTT本构模型能够很好地预测PEO水溶液在4:1收缩微流道中的流变行为。此外,还讨论了Weissenberg数和流道的几何形状对微流动行为的影响,随着Weissenberg数的增大,PEO水溶液的流速、压力和应力也随之增大,而圆弧过渡收缩口可以有效地避免涡流流动,提高挤出流场的稳定性。

The flow behavior of polyethylene oxide(PEO)aqueous solution with the mass fraction of 0.30%in a4:1 contraction microchannel was studied by the experimental and numerical methods in this paper.With finite element analysis software Polyflow,the exponential Phan-Thien-Tanner(PTT)constitutive model was applied to simulate the flow behavior of the solution in 4:1 right angle contraction microchannel and 4:1 arc transition contraction microchannel at Weissenberg numbers of 5.9,7.2,8.1 and 9.8.The results show that the experimental results agree well with the numerical simulation results.It is proved that the PTT constitutive model can well predict the rheological behavior of PEO aqueous solution in 4:1 contraction microchannel.Furthermore,the influence of Weissenberg number and geometry of the channel on the microscale flow behavior was discussed.With the increase of Weissenberg number,the flow velocity,pressure and stress of PEO aqueous solution also increase,and the arc transition contraction port can effectively avoid vortex flow and improve the stability of extrusion flow field.