1994 Fiscal Year Final Research Report Summary
Development of the bouble difusion augmentator of interface instability type by using an unsteady Lorentz force
| Project/Area Number |
05555057
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Fluid engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
YAMANE Ryuichiro Tokyo Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (50016424)
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| Co-Investigator(Kenkyū-buntansha) |
OSHIMA Shuzo Tokyo Institute of Technology, Faculty of Engineering, Research Associate, 工学部, 助手 (20143670)
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| Project Period (FY) |
1993 – 1994
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| Keywords | fluids engineering / magnetohydrodynamics / unstable wave / surface Wave / DC magnetic field / AC magnetic field / unsteady electromagnetic force / electrically conducting fluids |
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| Research Abstract |
Analyzes and experiments were conducted for the development of the bouble difusion augmentator of interface instability type by using an unsteady Lorentz force, and following conclusions were derived :
(1) In the case that the unsteady Lorentz force is generated by uniform horizontal AC magnetic field :
i) Unstable waves generated on the liquid metal surface oscillate in the same frequency as the AC magnetic field.
ii) Unstable conditions are dependent on 4 parameters ; the magnetic Reynolds number Rm, the Stuart number Np, the weber number we , and the Reynolds number Re.
iii) The waves which wave vector are parallel with the magnetic field are most unstable.
iv) In the case that both the Weber number We and the Reynolds number Re are fixed at some values, unstable boundary moves upward in tha omega-Np plane with a decrease of the magnetic Reynolds number, and the system becomes stable ; however, the relation between the frequency of the AC magnetic field and the wave number of the unstabl
… More
e wave hardly changes.
v) In the case that both the magnetic Reynolds number Rm and the Reynolds number are fixed at some values, unstable boundary moves to the right-hand side in the omega-Np plane and the wave number of the unstable wave decreases with a decrease of the Weber number.
vi) In the case that both the magnetic Reynolds number Rm and the Weber number are fixed at some values, unstable boundary moves upward in the omega-Np plane ; however, the relation between the frequency of the AC magnetic field and the wave number of the unstable wave hardly changes.
vii) The frequency of the AC magnetic field becomes higher, the induced electric current concentrate around the free surface and the temperature rises severely.
viii) Relatively strong magnetic field with a high frequency are needed for the genaration of unstable waves in the actual machine.
(2) In the case that the unsteady Lorentz force is generated by simulteneous imposition of horizontal DC and AC magnetic fields :
i) The waves with the same frequency as the AC magnetic field appear on the liquid metal surface.
ii) The optimum strength of the DC magnetic field that gives the waves of the largest amplitude exists and changes in value according to the strength of AC magnetic field.
iii) The oscilation mode depends not on the distribution of the magnetic field but on the shape of the container. Less
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