Magneto-hydrodynamic mixing

Gleeson, ). P., West, )., Magneto-hydrodynamic mixing, in Proceedings of the 5th International Conference on Modeling and Simulation of Microsystems, San )uan, Puerto Rico, 22-25 April 2002, Computational Publications, Boston, pp. 318-321 (2002). 

External energy sources for active mixing are, for example, ultrasound [22], acoustic, bubble-induced vibrations [23,24], electrokinetic instabilities [25], periodic variation of flow rate [26-28], electrowetting induced merging of droplets [29], piezoelectric vibrating membranes [30], magneto-hydrodynamic action [31], small impellers [32], integrated micro valves/pumps [33] and many others, which are listed in detail in Section 1.2. 

Fig. 18 Magneto-hydrodynamic disturbance (MHD) micromixer, (a) Cross-section view of an MHD mixer. MHD mixer comprises the following layers (7) channel bottom wall containing the electrodes (2) spacer layers that constitute the mixing chamber (i) cover plates (4) permanent magnet, (b) Deformation of fluid stream resulting from the application of a Lorentz body force (upper panel) and corresponding creation of eddies (lower panel) (Reprinted from [46] with permission. Copyright 2001 Elsevier)...

The term active mixer or active microimxef refers to a microfluidic device in which species mixing is enhanced by the application of some form of external energy disturbance. Typically, this disturbance is generated either by moving components within the micromixer itself, e.g. magnetically-actuated stirrers, or by the application of an external force field, e. g. pressure, ultrasound, acoustic, electrohydrodynamic, electrokinetic, dielectrophoretic, magneto-hydrodynamic, thermal, and so forth [1]. 

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