MAGNETIC FLUID DYNAMICS

Author: López López Modesto Torcuato.
Year: 2005.
University: GRANADA [www.ugr.es].
Place of defense: Facultad de Ciencias. Universidad de Granada..
Place of preparation: Facultad de Ciencias.

Summary: Magnetic fluids are a new type of complex fluids that have the interesting property of changing their flow properties under the application of external magnetic fields. Structurally, these fluids are made up of magnetic particles, and sometimes also non-magnetic, dispersed in liquid carriers. Depending on the type of particles dispersed, an initial classification of these suspensions include: (i) ferrofluidos, where the magnetic nanoparticles are dispersed phase, and (ii) fluids magnetorreológicos, in which the dispersed phase are magnetic microparticles. Due to the small size of its constituent particles, thermal energy dominates the energy of magnetic interactions in ferrofluidos, and under the action of external magnetic fields are only experiencing minor changes in viscosity. By contrast, in referring a fluid magnetorreológico the action of an external magnetic field, there are great changes in their rheological properties (effect magnetorreológico) even effort to develop threshold (minimum effort shear flow which makes suspension). This article describes the preparation of stable fluids belonging to both categories. Then we study their properties stability and magnetorreología. Finally they prepare a new type of magnetic fluids, called magnetic fluid compounds, which are suspended particles both micrométricas as magnetic nano and discusses their rheological properties and stability both in the presence and in absence of external magnetic fields.