2007 Fiscal Year Final Research Report Summary
Application of ultrasonic technique to investigate inner structures and flow behavior of functional fluids
| Project/Area Number |
17560159
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Fluid engineering
|
|---|
| Research Institution | Keio University |
|---|
Principal Investigator |
SAWADA Tatsuo Keio University, Faculty of Science and Technology, Professor (00162545)
|
|---|
| Project Period (FY) |
2005 – 2007
|
| Keywords | Magnetic Fluid / MR Fluid / Sound Velocity / Magnetic Field / Anisotrophy / Ultrasonic Wave / Attenuation / Cluster |
|---|
| Research Abstract |
Magnetic and magnetorheological (MR) fluids are typical magnetic functional fluids, which change their rheological properties when an external magnetic field is applied. A magnetic fluid is a stable colloidal suspension of small surfactant-coated magnetic particles -about 10 nm in diameter in a liquid carrier, such as water and hydrocarbon oil. On the other hand, the composition of an MR fluid is similar to that of a magnetic fluid, but with a typical magnetic particle size of 10 gm. Moreover, an MR fluid has controllable yield stress and high viscosity under a magnetic field. When an external magnetic field is applied to a magnetic or an MR fluid, some of the inner particles coagulate and form a clustering structure.
The properties of ultrasonic propagation velocity and attenuation in these fluids subjected to the magnetic field are measured precisely. The measurement scheme is based on the pulse method. Some interesting properties of ultrasonic propagation such as hysteresis are observed. Based on the experimental results, the relationship between these ultrasonic=, propagation properties and inner structures of these fluids is discussed.
|
