| Project/Area Number |
21K03884
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 19010:Fluid engineering-related
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| Research Institution | Okinawa Institute of Science and Technology Graduate University |
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Principal Investigator |
Haward Simon 沖縄科学技術大学院大学, マイクロ・バイオ・ナノ流体ユニット, グループリーダー (20812986)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2023: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2022: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2021: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| Keywords | extensional flow / rheology / micofluidics / viscoelasticity / flow stability / polymer solution / flow instability / microfluidics / viscosity / viscoelastic fluid |
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| Outline of Research at the Start |
Extensional viscosity of viscoelastic fluids is of fundamental importance in fluid handling and processing operations. Extensional viscosity depends on the fluid strain and strain-rate, and likely on the mode of deformation: uniaxial, planar or biaxial. The 3D microfabrication of geometries designed to measure the extensional viscosity in different deformation regimes will advance the measurement of the extensional properties of viscoelastic fluids. The results will aid the understanding and optimization of processes such as fiber spinning, ink-jet printing, blow-moulding, etc.
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| Outline of Final Research Achievements |
Simple fluids like water have a constant viscosity, but complex fluids like polymer solutions have a viscosity that can vary in response to flow. In a ‘stretching’ flow the viscosity of a polymer solution can increase dramatically, but this increase is hard to measure properly. In this project we produced highly precise microscopic glass channels to drive fluids in three-dimensions and to generate a flow field that stretches a polymer solution either along an axis or over a plane. These kinds of flows occur in processes such as fiber-spinning and film formation, where it is important to understand the properties and behavior of the complex fluids that are used. We showed for the first time that when stretching is along an axis the viscosity increase of a polymer solution is twice as large as when stretching is over a plane. On the other hand, we also showed that the flow is highly stable for planar stretching, but easily becomes unstable for axial stretching.
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| Academic Significance and Societal Importance of the Research Achievements |
The extensional rheology of complex fluids impacts many industrial and biological processes including fiber spinnning, inkjet printing, film formation, and blood flow. This project has contributed to improving the understanding and measurement of the extensional properties of complex fluids.
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