Numerical Study of Mixing and Mass Transfer in a Micromixer by Stimulation of Magnetic Nanoparticles in a Magnetic Field

Abstract

A numerical study on the hydrodynamics of ferrofluid flow and mass transfer characteristics in a Y‐type micromixer is performed. Computational fluid dynamics (CFD) simulation is accomplished to survey the behavior of ferrofluid flow subject to an external magnetic field and to specify its effect on the mass transfer between two immiscible liquid phases. The geometric reconstruction scheme (Geo‐Reconstruct) based on piecewise linear interpolation is applied to reconstruct the two‐phase interface. The results of CFD modeling are validated by experimental data, and good agreements are achieved, with a maximum relative error for the extraction efficiency of about 7.52 %. This research work shows that ferrofluid stimulation by a magnetic field can be an efficient mixing factor in microdevices.

Investigation of mixing performance in a semi‐active T‐micromixer actuated by magnetic nanoparticles: Characterization via Villermaux–Dushman reaction

“…This statement can be confirmed by the CFD results in our previous study, [ 13 ] which proved the deflection of the MNPs in the direction of the magnetic field and their transverse motion. The instability of ferrofluid has a positive effect as it causes inducing secondary flow or convective flow in the mixing channel.…”

“…[29] Under these conditions, micromixing occurs rapidly because of the more efficient transport of carrier fluid of MNPs toward the region with the highest flux. [48] This statement can be confirmed by the CFD results in our previous study, [13] which proved the deflection of the MNPs in the direction of the magnetic field and their transverse motion. The instability of ferrofluid has a positive effect as it causes inducing secondary flow or convective flow in the mixing channel.…”

“…[12] The mechanism of the mixing in the microreactors occurs via molecular diffusion and convection, which depends on the applied operating conditions and the flow geometry. [13][14][15] The mixing time is short in microreactors, even in the laminar flow regime, due to short diffusion radial lengths. Besides, the mixing time can also be changed by generating eddies.…”

Novel Study on the Mixing Mechanism of Active Micromixers Based on Surface Acoustic Waves

“…Active micromixers mainly rely on external energy input to promote fluid mixing. External energy sources include electric, magnetic, and acoustic fields. − Active micromixers have the advantages of high mixing efficiency, good mixing effect, and short channel length . Some external energy sources require contact with the fluid, which disturbs the fluid.…”

Laminar Fluid Mixing in Micromixers: Description of Pull‐Push Effects

“…Acoustic, electric, and magnetic fields, to name but a few, can act as external forces [14][15][16][17] to disturb the fluids contact surface and thus promote mass transfer rate in active micromixers. Passive mixers need special design changes or characteristic changes in their geometries to obtain better mixing performance [18][19][20][21][22][23][24][25][26][27]. Simply introducing layers [21], grooves [28], obstacles [29], baffles [30], curves [31], and ridges [32] in the fluid flow direction can afford high mixing quality.…”