拡大流れにおける高分子流体の流動配向

抄録

Flow-induced orientation of xanthan gum aqueous solutions in a planar channel with an abrupt expansion were examined by measurement of the flow-induced birefringence along the centerline of the channel. Four kinds of the xanthan gum solutions with different concentrations (0.45, 0.5, 0.7, 0.9 wt.%) were tested in this experiment. Characteristic times were evaluated from G′ and G′′ curves respectively. The birefringence changes were delayed corresponding to the characteristic times. Typical sizes of regions where the flow structure of polymers were affected by the abrupt expansion were estimated with the birefringence changes. The normalized sizes have a good correlation with a viscoelastic factor (apparent Weissenberg number) estimated in upstream region regardless of the concentrations of the solution.