Analytical Study, Numerical Modelling and Experimental Results of the Forces which Act in the Magnetic Liquid Placed between the Poles of an Electromagnet


This paper makes an analytical study, a numerical and an experimental analysis of the magnetic forces which act in magnetic liquids during the experiment called Quincke’s effect. Quincke’s effect consists in the rise of the magnetic liquid between the poles of an electromagnet. In ferrohydrodynamics theory, the forces acting in the magnetic liquid are not always treated in a uniform manner. The main goal of this paper is to give a consistent macroscopic view, pointing out the importance of the magne-tostriction in the force localization understanding. If the absence of the magnetostrictive term in the forces expres-sion leads to an exclusively superficial localization of the forces, the presence of this term leads both to a superficial localization of forces as well as their presence in the mag-netic liquid volume. Moreover, in the magnetic liquid rise, the volume forces have a significant contribution than the surface forces, so the magnetostrictive term shall not be neglected. In this analysis, the magnetic liquid will be considered as a linear and nonconducting medium placed in a stationary (or quasistationary) field. In order to support the analytical study, a numerical analysis of the magnetic forces and some qualitative experiments were made. The value of the magnetic field forces which act in the magnetic liquid were established in Matlab using the magnetic field strength established by FEM analysis. Analyzing the numerical results and the magnetic liquid deformation obtained by ex-periments, the main conclusion consists in the fact that the magnetostrictive term has an important contribution in the localization of the forces, so it shall be taken into consideration. images