2006 Fiscal Year Final Research Report Summary
Development of intelligent micro cooling system utilizing ER effects
| Project/Area Number |
17560138
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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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, Institute of Science and Technology, Associate professor (20143753)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Liquid crystal / ER effect / Yield pronerty / Functional fluid / Flow rate control / Smectic liquid crystal / Phase change |
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| Research Abstract |
We have tried to develop a new cooling system utilizing liquid crystal which shows ER (electro-rheological) effect under electric fields applied and phase change by the temperature control. In the early stage of this project, it was found that flow rate of liquid crystal was controllable with applying electric fields. But, it was also clarified that it was difficult to obtain higher cooling efficiency than the water system because of higher viscosity and similar heat transfer property of liquid crystal. Hence we have examined the applicability of smectic liquid crystal as a functional fluid to stop the flow utilizing its yield property controlled with the electric field strength and the temperature.
In the second stage, ER characteristic in smectic phase of the liquid crystal have been investigated utilizing a parallel-plate type rheometer. The strength of the alignment structure in the Smectic phase is experimentally examined from the change in yield stress under various conditions. When the electric field strength was low, the yield stress was almost the same as that obtained under no electric field. Above a threshold of DC electric field, the yield stress increased and then became constant. Moreover, photographs were taken in yield process, and it is found that the collapse of the structure under the DC electric field is generated not uniformity but like spots.
In the final stage, the yield properties with two dimensional channels in the pressure flow have been measured with the same smectic liquid crystal. The growth of smectic phase structure at the entrance of the channel increased the stop valve effect of the system.
From these results, it is considered that the flow control with the liquid crystal is helpful to develop intelligent cooling systems.
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Research Products
(12 results)
