Investigation on flow property and flow-induced structure of worm-like micelle surfactant solutions in abrupt contraction and expansion flows

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04191
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19010:Fluid engineering-related
• Research Institution: Niigata University
• Principal Investigator: USHIDA Akiomi 新潟大学, 自然科学系, 准教授 (10582976)
• Co-Investigator(Kenkyū-buntansha): 佐藤 大祐 新潟大学, 研究推進機構, 助教 (70778703)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: ミセル溶液 / 流動特性 / 流動誘起構造 / 急縮小急拡大流れ / スリット

Outline of Final Research Achievements

Flow properties of several types of micellar solutions passing through small slits (abrupt contraction and expansion flow) were investigated. The resultant pressure drops of water and glycerol solutions agreed with the numerical predictions, On the other hand, the higher pressure drops of surfactant solutions with rod-like micelles were obtained. It was also clarified that the experimental results were dependence of the type of surfactant. In order to clarify the mechanism of the anomalous flow properties, flow-induced structure (the orientation of the rod-like micelle) was measured by polarized-imaging analysis. The relationship between increase in pressure drop and flow-induced structure was obtained. Moreover, the relationship in characteristic strain rate (Reynolds number and Weissenberg number) exhibited.

Free Research Field

流体工学

Academic Significance and Societal Importance of the Research Achievements

流体内部に構造を形成する流体は複雑流体と呼ばれ，代表例の一つとしてミセル溶液がある．このような流体は化粧品や食品の流体モデルともなる．このような流体は作製・塗布過程において単純せん断だけではなく，伸張の効果が付与される．本研究成果は伸張の効果が付与された際のミセル溶液は特徴的な流動特性や流動誘起構造（ミセルの配向状態）が発現することを明らかにした．すなわち，製造過程や塗布形成過程などにおける新たな学術的展開に繋がる知見であり，複雑流体分野における新たな構成方程式（応力と応力以外の物理量を関係付ける方程式）構築に繋がる．