Finite Element Simulation of Heat Transfer in Ferrofluid

“…where B is the magnetic flux density and H is the intensity of the magnetic field. Also, we shall mention here that the magnetic stress tensor can be expressed in the following form (Rosensweig 1984;Strek 2008):…”

Section: Modelling Of Magnetic Field Distributionmentioning

confidence: 99%

Magnetofluidic-based controlled droplet breakup: effect of non-uniform force field

2022

View full text Add to dashboard Cite

We report the breakup dynamics of a magnetically active (ferrofluid) droplet in a T-shaped Lab on a Chip (LOC) device under the modulation of a non-uniform magnetic field. We adhere to high-speed imaging modalities for the experimental quantification of the droplet splitting phenomenon, while the underlying phenomenon is supported by the numerical results in a qualitative manner as well. On reaching the T-junction divergence, the droplet engulfs the intersection fully and eventually deforms into the dumbbell-shaped form, making its bulges move towards the branches of the junction. We observe that the asymmetric distribution of the magnetic force lines, acting over the T-junction divergence, induces an accelerating motion to the left of the moving bulge (since the magnet is placed adjacent to the left branch). We show that the non-uniform force field gradient allows the formation of a hump-like structure inside the left moving bulge, which triggers the onset of augmented convection in its flow field. We reveal that this augmented internal convection developed in the left moving volume/bulge, on becoming coupled to the various involved time scales of the flow field, leads to the asymmetric splitting of the droplet into two sister droplets. Our analysis establishes that, at the critical strength of the applied forcing, as realized by the critical magnetic Bond number, the flow time scale becomes minimum at the left branch of the channel, leading to the formation of larger sized sister droplets therein. Inferences of the present analysis, which demonstrates a plausible means of independently controlling the size of the sister droplet by manoeuvring the applied force field gradient, will provide a potential solution for rapid droplet splitting, which typically finds significant importance in point-of-care diagnostics.

show abstract

“…The body force F in Eq. (2) represents the Kelvin body force (i.e., the force that a magnetic fluid experiences in a spatially non-uniform magnetic field per unit volume) and can be calculated as (Strek, 2008):…”

Section: Fluid Flowmentioning

confidence: 99%

Modeling of mass transfer enhancement in a magnetofluidic micromixer

et al. 2019

View full text Add to dashboard Cite

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.

show abstract

Finite Element Simulation of Heat Transfer in Ferrofluid

Cited by 5 publications

References 8 publications

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

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

Magnetofluidic-based controlled droplet breakup: effect of non-uniform force field

Modeling of mass transfer enhancement in a magnetofluidic micromixer

Contact Info

Product

Resources

About