Modeling of mass transfer enhancement in a magnetofluidic micromixer

Abstract

The use of magnetism for various microfluidic functions such as separation, mixing and pumping has been attracting great interest from the research community, as this concept is simple and effective and of low cost. Magnetic control avoids common problems of active microfluidic manipulation such as heat, surface charge, and high ionic concentration. The majority of past works on micro magnetofluidic devices were experimental, and a comprehensive numerical model to simulate the fundamental transport phenomena in these devices is still lacking. The present study aims to develop a numerical model to simulate transport phenomena in microfluidic devices with ferrofluid and fluorescent dye induced by a non-uniform magnetic field. The numerical results were validated by experimental data from our previous work, indicating a significant increase in mass transfer. The model shows a reasonable agreement with experimental data for the concentration distribution of both magnetic and non-magnetic species. Magnetoconvective secondary flow enhances the transport of nonmagnetic fluorescent dye. A subsequent parametric analysis investigated the effect of the magnetic field strength and nanoparticle size on the mass transfer process. Mass transport of the fluorescent dye is enhanced with increasing field strength and size of magnetic particles.

Microfluidic Synthesis and Purification of Magnetoliposomes for Potential Applications in the Gastrointestinal Delivery of Difficult-to-Transport Drugs

“…The second method was based on a mixture model approach to simulate a dispersed phase, considered a ferrofluid (i.e., a suspension of magnetic nanoconjugates in water) due to the high concentration of nanoparticles in the domain. Several recent reports support this assumption (rather than considering individual particles) for FEM simulations, since it leads to results that are closer to those obtained experimentally [42][43][44][45][46]. In this case, the implemented COMSOL modules were the "mixture model with laminar flow", the "magnetic field without current", and "diluted species' transport".…”

“…where P is the pressure, µ is the dynamic viscosity of the fluid, ρ c and ρ d the continuous phase density and dispersed phase density, Φ d the volume fraction of the dispersed phase, m dc the turbulent dispersed phase diffusion, and F the body forces, which in this case are described by the Kelvin body force due to a spatially non-uniform magnetic field according to Equation ( 13) [46]:…”

Understanding Interdependencies between Mechanical Velocity and Electrical Voltage in Electromagnetic Micromixers

“…Their study demonstrated that the T-shaped mixer’s junction shape and pit diameter critically affected the mass transfer coefficients as chaotic advection was generated by the modification of the mixing channel shape. Chandan Kumar and Nguyen [ 39 ] developed a numerical model of magnetic nanoparticles and fluorescent dye under a nonuniform magnetic field. They performed a parametric analysis of the mass transfer process to scrutinize the magnetic field strength and nano-particle size effects in a magnetofluidic micromixer.…”

Magnetofluidic mixing of a ferrofluid droplet under the influence of a time-dependent external field

“…Albeit that several underlying issues of the magnetic field modulated micromixing analysis have been well explored (see Wang et al 2008;Roy et al 2009;Tsai et al 2009;Wen et al 2009;Zhu & Nguyen 2012;Gao et al 2015;Hejazian et al 2016;Munaz et al 2017;Nouri et al 2017;Kumar et al 2019), the phenomenon of magnetophoresis, which is effectively used in manipulating microflows, in the context of droplet-based micromixing has been sparsely studied. It may be mentioned here that, in the paradigm of droplet-based mixing, the rotating magnetic field has been used in a synergetic way to augment the mixing appreciably (Roy et al 2009;Gao et al 2015;Munaz et al 2017).…”