Heat and Mass Transfer Phenomena

Abstract

This section deals with main problems of the heat and mass transfer in magnetic colloids. The analysis is mainly based on the general model given in the Chapter written by R. E. Rosensweig. Hydrodynamic and thermal problems are simplified considering incompressible liquids and neglecting the effects of polarization and electric conductivity as well as ignoring some other secondary effects that usually can be neglected in ferrofluid experiments. Contrarily, the analysis of mass transfer accounts for new sedimentation phenomena and cross effects of interrelated heat and mass transfer. Since the description given by Rosensweig is of general theoretical nature, while the present work mainly focusses on experimental problems, the various equations needed will not be cited from Rosensweig’s article but from the original literature since the transfer from the general model to the experimentally needed relations is often cumbersome and would exceed the frame of this presentation.

The following problems shortly are discussed: the equation of energy conservation accounting for new adiabatic effects and dissipation due to internal rotation, the thermomagnetic and magnetosolutal instabilities, the specifics of magnetic convection in fluids of non-uniform temperature and concentration, the magnetophoresis and thermodiffusion of colloidal particles under the effect of a magnetic field and some phenomena of combined thermal and Soret-driven convection.