1995 Fiscal Year Final Research Report Summary
Squeezing Flow of Functional Fluids in Narrow Gaps
| Project/Area Number |
06650198
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Fluid engineering
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| Research Institution | Niigata University |
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Principal Investigator |
NARUMI Takatsune Niigata University Faculty of Engineering Associate Professor, 工学部, 助教授 (20143753)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Tomiichi Niigata University Faculty of Engineering Professor, 工学部, 教授 (80016592)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Functional Fluid / Liquid Crystalline Polymer / Squeezing Flow / Narrow Gap / Historical Effect / Liquid Crystal / Electrorheological Effect |
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| Research Abstract |
Experimental examination has been conducted on radial flows and the subsequent squeezing flow of liquid crystalline polymer (LCP) solutions between two parallel circular flat plates with a narrow gap. After the steady radial flow was stopped and a pause time is taken, then the squeezing flow is started. Forces transmitted with the liquid film are measured and flow alignment patterns of the test fluids are simultaneously observed. The following points are clarified. (1) Even if the squeezing motion is the same, the intensity of the pre-shear deformation (radial flow) gives great influence on the flow alignment patterns and the transmitted force. (2) The similar influence of the pause time on the squeezing flows is also observed. (3) The above results show that the alignment patterns and the functional of the LCP will be controlled by the flow historical effects. (4) In the case with the weak pre-shear flow, the squeezing flow of the LCP is approximately estimated with the Carreau model.
We have also studied a squeezing flow of a nematic liquid crystal (LC) in a narrow gap. At the first stage, characteristics of the LC in a two-dimensional Poiseuille flow under electric fields have been examined in the narrow gap of 50-100mm. A maximum apparent viscosity of the LC,increased by the electric field, is 4 to 5 times larger than with no electric field and this ER effect is in proportion to the square of the electric field strength. Estimation of the ER effect in the squeezing flow of LC utilizing above results shows that constant ER effects are expected in the squeezing flow because the influence of the shear thinning of the viscosity is counterbalanced by the increase of the electric field strength with the decrease in the gap size.
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