1989 Fiscal Year Final Research Report Summary
STUDY OF THERMO-MAGNETIC CONVECTION IN TEMPERATURE-SENSITIVE MAGNETIC FLUIDS
| Project/Area Number |
63460185
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
資源開発工学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
NAKATSUKA Katsuto TOHOKU UNIVERSITY, FACULTY OF ENGINEERING, DEPARTMENT OF RESOURCES ENGINEERING, PROFESSOR, 工学部, 教授 (60005345)
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| Co-Investigator(Kenkyū-buntansha) |
SATOH Motoyuki TOHOKU UNIVERSITY, FACULTY OF ENGINEERING, DEPARTMENT OF RESOURCES ENGINEERING,, 工学部, 助手 (40005369)
NAMBU Masateru TOHOKU UNIVERSITY, FACULTY OF ENGINEERING, DEPARTMENT OF RESOURCES ENGINEERING,, 工学部, 助手 (10005340)
ABE Mamoru TOHOKU UNIVERSITY, FACULTY OF ENGINEERING, DEPARTMENT OF RESOURCES ENGINEERING,, 工学部, 助手 (50005310)
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| Project Period (FY) |
1988 – 1989
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| Keywords | magnetic fluid / temperature-sensitive magnetic fluid / thermo-magnetic convection / convective heat transfer / 熱サイフォン |
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| Research Abstract |
A temperature-sensitive magnetic fluid, which includes a ultrafine magnetic particle with a relatively low Curie temperature is accompanied with magnetically induced thermal convection by being heated in magnetic field. This phenomenon is noticed with scientific interests because a thermal convection can be intentionally controlled by use of magnetic field. In this study the synthesis of ultrafine magnetic particle desired for the preparation of temperature-sensitive magnetic fluid is examined. The magnetic fluid obtained by using Mn-Zn ferrite shows more remarkable temperature dependency of magnetization than those which has been reported, and is used for the thermal convection studies. In order to study a heat transfer from solid surface into magnetic fluid, a thin platinum wire is used as a heater and a resistive thermometer. By measuring a heat transferred from wire surface under an applied magnetic field as a function of temperature difference between solid surface and bulk liquid, it was found that the efficiency of heat transfer is strongly influenced by a magnetic field and increases in maximum twice of the value in the absence of magnetic field. Further, a model experiments of 'Magnetic fluid heat siphon' is conducted in order to confirm the existence and utilization of thermal convection. The device is composed of a container of aluminum rod with a cylindrical hole in it, heater winding at one end of the container. The magnetic fluid is filled in the container, and the temperature distribution of the wall and inside of the fluid were measured during heating one end of the container under a magnetic field applied. As a result, the efficiency of heat transfer of the siphon increased by applying magnetic field, and main factor which controls the total efficiency of the siphon is the heat transfer from the liquid to cooling wall at the end of the siphon where magnetic field is not applied.
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