磁性流体管内振動流の超音波による速度分布計測と流体内部構造変化の流動に及ぼす影響(<小特集>非ニュートン性,機能性を示す複雑流体の流動と応用)

Abstract

Oscillating pipe flow of a magnetic fluid was investigated experimentally by using the Ultrasonic Velocity Profiler (UVP) method. The test liquids are two kinds of water-based magnetic fluid W-40 and MSG11. UVP method is a useful technique for measuring the velocity components of a magnetic fluid. When this method is applied to magnetic fluid flow, it is necessary for the ultrasonic propagation velocity to be accurate. However, when an external magnetic field is applied to a magnetic fluid, some of the inner particles coagulate and form clustering structures. These clustering structures affect the ultrasonic propagation. Therefore, the properties of ultrasonic propagation in test magnetic fluids were also analyzed exactly before the measurement by UVP. Based on this analysis, UVP method is applied to magnetic fluid. In the result of velocity profile measurement, unique phenomena of oscillating pipe flow of the magnetic fluids subject to magnetic field were observed. It seems that the change of clustering structures under magnetic field cause these unique phenomena.