Flow behavior of viscoelastic fluid in high speed planar elongational flow

提出了利用芯/鞘流动产生高延伸率的平面延伸流的技术。在这项研究中，我们对粘性流体和粘弹性流体在流动中的流动行为进行了实验观察。从流动显示和速度分布的结果可以观察到，对于粘弹性流体，岩心流体的流动行为呈现出四种流型。接下来，我们用交叉Nicols方法计算了拉长流体的分子取向分布。结果表明，在拉长流区，分子取向的测量不依赖于流池到侧壁的距离。结果表明，分子取向沿流动池中心线的分布可以讨论其对流动的贡献延伸性。

It is proposed that the technique to generate planar elongational flow with high elongational rate by using core/sheath flow. In this study we carried out experiments to observe flow behavior for both viscous fluid and viscoelastic fluid in the flow. It is observed for viscoelastic fluid that flow behavior of the core fluid shows four kind of flow patterns from result of flow visualization and velocity profile. Next, we evaluated molecular orientation profile of elongated fluid by using crossed nicols method. As the results, measure of molecular orientation doesn’t depend on the distance to sidewalls of the flow cell in elongational flow region. It is shown that contribution elongational property to the flow can be discuss from results of distribution of molecular orientation along center line of the flow cell.