1991 Fiscal Year Final Research Report Summary
Oscillation of Magnetic Fluid in a Pipe
| Project/Area Number |
02650123
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Fluid engineering
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
OYAMA Tadamasa Tohoku Univ., Inst., Fluid Sci., Assistant, 流体科学研究所, 助手 (80006189)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SATO Akira Tohokugakuin Univ., Engng. Dept., Lecturer, 工学部, 講師 (30048805)
KAMIYAMA Shinichi Tohoku Univ., Inst., Fluid Sci., Professor, 流体科学研究所, 教授 (80006171)
|
|---|
| Project Period (FY) |
1990 – 1991
|
| Keywords | Magnetic Fluid / Magnetic Field / Oscillatory Flow / Magnetic-optics |
|---|
| Research Abstract |
A study of oscillation of a magnetic fluid plug in a U-tube is conducted in connection with the development of a magnetic fluid plug actuator.
Oscillating characteristics of magnetic fluid plug in a U-tube are strongly influenced by the behavior of the magnetic fluid near the pole pieces.
Experimental study on the oscillating characteristics of the plug is conducted to obtain the damping coefficient and loss coefficient in the oscillation of the plug in a magnetic field by changing the inner diameter of the tube. It is clarified that the measured loss coefficient is much larger than the frictional loss coefficient calculated based on the ordinary magnetic fluid theory, and the extra loss is induced with the reduction of the cross section to the fluid movement near the pole piece.
The reduction of the cross section in the tube may be caused by the particle agglegation.
In order to verify the particle aggregation in a plug, the maximum and minimum intensities of the transmitted ray and its rotating angle are measured in a thin film of magnetic fluid(10mm X 0.5mm X 60mm)in nonuniform magnetic field by measuring apparatus for magnet-optical birefringence.
Particle density distributions in the film are observed.
When the magnetic field strength increases, the particles are attracted to the poles and the area of particle aggregation is reduced.
It is also confirmed that the removal and reattachment of the particles are repeated near the aggregated area, since the transmissivity shows wave behaviour even in a steady magnetic field and the rotating angle shows symmetrical distribution in regard to the center of the magnetic field.
|
