平面急縮小流れにおけるセルロースナノファイバー分散系の流動挙動

抄録

The fiber orientation of a cellulose nanofiber (CNF) suspension in a plane channel with an abrupt contraction flow was investigated using flow-induced birefringence (FIB) measurement. The velocity profiles were also measured in order to associate the flow field with the fiber orientation field. In this study, 4:1 abrupt contraction channels with contraction ratios of 2, 4 and 8, and aspect ratios of 1 and 2 were tested in the experiments. 0.5 wt% CNF was used as a test fluid and how the fiber orientation developed near the centerline after the abrupt contraction was examined. As a result, the birefringence increased dramatically near the contraction and the birefringence decreased gradually after the abrupt contraction and reached a constant value. Furthermore, it was found that the distance where the birefringence reaches a constant value does not affect by contraction ratio, aspect ratio and flow rate.