Bubble behavior in magnetic fluid under a nonuniform magnetic field

Experimental study is made to clarify the effects of nonuniform magnetic field on bubble behavior in a magnetic fluid. The behavior of vapor bubbles is visualized with ultrasonic wave echo under the nonuniform magnetic field. It is found that the void fraction in two-phase flow decreases with increase in the magnetic field due to the effect of magnetic body force. Furthermore, the effects of nonuniform magnetic field on translational motion and deformation of a single gas bubble in a magnetic fluid are experimentally examined using a transparent thin duct, called a Hele-Shaw cell. The experimental results indicate that a single bubble is decelerated in the region of positive magnetic field gradient and accelerated in the region of negative magnetic field gradient, and that it is elongated in the direction of the magnetic field.