Dependence of flow behavior of complex fluids in elongational flows and change in structure on elongational property of fluids

复杂流体在拉伸流动中的流动行为以及结构变化对流体拉伸特性的依赖性

• 批准号: 10450076
• 负责人: NAKAMURA Kiyoji
• 金额: $ 6.98万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10450076/
• 关键词: elongational flow; complex fluid; viscoelastic fluid; liguid crystalline polymer; rheometer; elongational viscosity; レオメ-タ; 繊維懸濁液; 結晶高分子

We considered flows in which elongational property of complex fluids played an important part. In the present study, we chose polymer solutions (viscoelastic fluid) and liquid crystalline polymers from many complex fluids.In the study of the flow of polymer solutions, velocity measurement of start-up flow in both a rectangular contraction channel and a rectangular expansion channel was carried out using a laser Doppler velocimeter (LDV). Experiment on flow visualization was also carried out. In addition, viscoelastic star-up flow was numerically investigated. The results indicated that the flow near the contraction and expansion was three-dimensional and the flow behavior of viscoelastic fluids was more complex than that of Newtonian fluids. The results of the numerical simulation showed that the behavior near the contraction and expansion related to the elongational property of polymer solutions.In study of flow of liquid crystalline polymers, coating flow, one of elongational flows, was investgated. Homogeneous surface alignment of liquid crystals (5CB) was observed for films formed by coating flow with aqueous solutions of hydroxypropylcellulose (HPC). The results of the present study suggested that the flow-induced anisortopic orentation of HPC molecules is responsible for the homogeneous surface alignment of 5CB.Moreover, a filament-stretching rheometer was made, and growth of the uniaxial elongational viscosity aqueous solution of polyacrylamide was measured.

我们考虑了复杂流体的拉伸性质起重要作用的流动。本文从众多复杂流体中选取了聚合物溶液（粘弹性流体）和液晶聚合物溶液，利用激光多普勒测速仪（LDV）对聚合物溶液在矩形收缩通道和矩形膨胀通道中的启动流动进行了测量。并进行了流场显示实验。此外，对粘弹性起动流进行了数值研究。结果表明，在收缩和膨胀附近的流动是三维的，粘弹性流体的流动行为比牛顿流体复杂。数值模拟结果表明，聚合物溶液在收缩和膨胀附近的行为与聚合物溶液的拉伸性质有关。对于通过羟丙基纤维素（HPC）水溶液涂布流形成的膜，观察到液晶（5CB）的均匀表面排列。研究结果表明，流动诱导的HPC分子的异位取向是5CB表面均匀排列的原因。此外，自制了一台单轴拉伸流变仪，测量了聚丙烯酰胺水溶液的单轴拉伸粘度的增长。

项目成果

Takehiro Yamamoto, Hideki Akiyoshi, Kiyoji Nakamura: "Numerical Simulation of Viscoelastic Flow in Three-Dimensional Rectangular Abrupt Contraction Channels"J. Text. Mach. Soc. Japan (English Ed.). Vol. 45 (3). 63-70 (1999)

Takehiro Yamamoto、Hideki Akiyoshi、Kiyoji Nakamura：“三维矩形突变收缩通道中粘弹性流的数值模拟”J。

Takehiro Yamamoto: "Numerical Simulation of Viscoelastic Flow in Three-Dimensional Rectangular Abrupt Contraction Channels"J.Textile Machinery Society of Japan (English Ed.). 45・3. 63-70 (1999)

Takehiro Yamamoto：“三维矩形突然收缩通道中粘弹性流动的数值模拟”J.日本纺织机械学会（英文版）45・3（1999）。

Noriyasu Mori, Masateru Morimoto, Kiyoji Nakamura: "Hydroxypropylcellulose Films as Alignment Layers for Liquid Crystals"Macromolecules. Vol. 32 (5). 1488-1492 (1999)

Noriyasu Mori、Masateru Morimoto、Kiyoji Nakamura：“羟丙基纤维素薄膜作为液晶取向层”大分子。

Takehiro Yamamoto: "Numerical Simulation of Viscoelastic Flow in Three-Dimensional Rectangular Abrupt Contraction Channels"J. Textile Mochinery Society of Japan (English Ed). 45・3. 63-70 (1999)

Takehiro Yamamoto：“三维矩形突然收缩通道中的粘弹性流动的数值模拟”J.日本纺织机械学会（英文版）45・3（1999）。

Noriyasu Mori: "Hydroxypropylcellulose Film as Alignment Layers for Liquid Crystals"Macromolecules. 32・5. 1488-1492 (1999)

Noriyasu Mori：“作为液晶取向层的羟丙基纤维素薄膜”32・5 1488-1492 (1999)。