Eventos Anais de eventos
ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
ANALYSIS OF MAGNETIC FLUID DISPLACEMENT IN CAPILLARIES
Submission Author:
Douglas Daniel de Carvalho , SP
Co-Authors:
Douglas Daniel de Carvalho, Rafael Gontijo, Francisco Ricardo Cunha
Presenter: Douglas Daniel de Carvalho
doi://10.26678/ABCM.ENCIT2018.CIT18-0039
Abstract
This work consists of a theoretical, numerical and experimental study to determine both the shape and vertical displacement of a free surface formed between a ferrofluid and a non-magnetic fluid, confined between two vertical plates. The presence of an external magnetic field applied by a permanent magnet arbitrarily positioned in space is considered. A new mathematical model is proposed, leading to a nonlinear differential equation that governs both the shape and the vertical displacement of the free surface due to capillary and magnetic effects. The applied field considered in this work satisfies the Ampère-Maxwell equation in the magnetostatic limit. This equation is numerically solved by direct integration using a fourth order Runge-Kutta method, coupled with a Newton-Raphson scheme. The numerical code is validated by means of some analytical solutions valid on specific asymptotic limits and by experimental results. Experimental measurements of surface tension, density and vertical displacement of Newtonian fluids in capillaries are also presented. Contact angles were also calculated. The influence of the variation of the physical variables concerning the physics of the problem on the shape and on the vertical displacement is evaluated. An increase in the intensity of the magnetic effects resulted in an increase in the vertical displacement and in the asymmetric degree of the free surfaces.
Keywords
Magnetic fluids, capillarity, Magnetic pressure, Meniscus shape/displacement, Contact angle calculations
