Microconvection and mass transfer near bodies in non-uniformly magnetized ferrofluid

V. Frishfelds - E. Blums

Institute of Physics, University of Latvia, 32 Miera street, LV-2169 Salaspils, Latvia

Abstract
Experimental observations of the magnetic fluid behaviour around a grid subjected to a magnetic field shows that the presence of a temperature gradient creates a notable separation of the fluid between the sides of the grid with different temperatures. Some separation of the ferrofluid occurs also in the absence of a magnetic field due to the usual Soret effect. Our aim here is to discuss in more detail the ferrofluid convection and its subsequent separation under the action of magnetic field force, resulting in a magnetic Soret effect. Understanding of the directed mass transfer in a non-uniformly magnetized ferrofluid is still insufficient, and different opinions on the role of various mechanisms are present. Therefore, a detailed description of heat and mass transfer phenomena is required. The heat and mass transfer phenomena are analyzed numerically by a two-dimensional (2D) macroscopic model in order to estimate the role of convection around micron-sized bodies (microconvection). Particularly, a grid, consisting of a large number of equidistantly spaced non-magnetic or magnetic cylinders, is considered. Figs 3, Refs 3.