The Loss of Continuity in a Liquid Ring Formed by a Magnetic Fluid

Abstract

A magnetic fluid ring, which can be compared to a liquid O-ring, held at a given place by a magnetic field is used for various applications, such as seals, compressors, dampers, or sensors. The work of this type of system is the result of a number of factors, such as the distribution and magnitude of the magnetic field in the gap, rheological and magnetic properties, physical properties of the surrounding environment (interfacial phenomena) and operating conditions (differential pressure and relative velocity). The research area of this publication is related to the recognition and assessment of how the magnetic fluid properties influence the mechanism of the local loss of continuity for a single liquid ring. This applies to the case when the differential pressure on two sides of the magnetic fluid-free surface exceeds a critical value and a leak channel is formed. Previous studies have shown that the process of equalizing the pressure difference in this type of system is related to pressure jumps. This phenomenon has not been linked to such properties as saturation magnetization, dynamic viscosity or surface tension. This paper takes these factors into account. In addition, the shape of the stage (trapezoid and rectangle) on which the fluid is held and the magnetic field value are considered. The loss of continuity is an important issue and the obtained results allow this problem to be better understood and the magnetic fluid to be chosen for appropriate working conditions, e.g., in the case of multistage seals. The studied phenomenon may also contribute to the development of new types of pressure regulators or sensors.