Abstract
Flow structures of a polymer solution in a planer channel with a 4:1 abrupt contraction have investigated utilizing an optical rheometric device which is combined with a microscope. Distributions of flow-induced birefringence and velocity field were measured with Xanthan gum solution. The measurement of the birefringence was conducted in every 100μm step along the width direction of the channel. The birefringence measured around the centerline of channel became larger in the converging flow generated in the upstream region of the abrupt contraction. Moreover, in this region, average orientation of the polymer molecules were agree with the flow direction defined with velocity vectors. It is considered that contribution of the elongational flow and the shear flow generated in this region of the planer channel to stretch the polymer molecules has same direction.
