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Field-Substance Interactions in Magnetically Driven Micro-Stirring Devices
Alexandru M. Morega, Mihaela Morega and Sebastian C. Faur

The growing demand for on-chip bio-chemical analysis systems has triggered the study of micro-fluidic flow and its control into an active area of research. In such small systems most of chemical and biological reaction processes are performed in liquid and suspension media, and the flow is laminar, at low Reynolds numbers. In molecular biology studies magnetic beads coated with ligand are used for selective separation of bio-molecules from the mixture by magnetic field control.

This paper reports mathematical models and numerical simulation results of micro-mixing devices, where quasistatic magnetic fields produced by sequentially switched DC currents are used to mix the working magnetic fluid, forced to flow through a rib walled channel. The body forces in the magnetized fluid perturb the otherwise laminar flow, into a mixing system. The study is concerned also with the heat transfer problem posed by the Joule effect produced by the electric currents. Apparently, for the assumed working conditions the temperature profile within the structure exhibits moderate levels, hence there is no stringent need to consider the temperature dependence of the fluid magnetization.

Keywords: Magnetic mixing, micro-total-analysis-system, mathematical modeling, numerical simulation.

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