scholarly journals NUMERICAL STUDY OF THE ROSENSWEIG INSTABILITY IN A MAGNETIC FLUID SUBJECT TO DIFFUSION OF MAGNETIC PARTICLES

2010 ◽  
Vol 15 (2) ◽  
pp. 223-233 ◽  
Author(s):  
Olga Lavrova ◽  
Viktor Polevikov ◽  
Lutz Tobiska
Keyword(s):  
Magnetic Field ◽  
Free Surface ◽  
Magnetic Fluid ◽  
Magnetic Particles ◽  
Numerical Study ◽  
Fluid Layer ◽  
Classical Problem ◽  
Parametric Representation ◽  
Field Configuration ◽  
Wide Range

The present study is devoted to the classical problem on stability of a magnetic fluid layer under the influence of gravity and a uniform magnetic field. A periodical peak‐shaped stable structure is formed on the fluid surface when the applied magnetic field exceeds a critical value. The mathematical model describes a single peak in the pattern assuming axial symmetry of the peak shape. The field configuration in the whole space, the magnetic particle concentration inside the fluid and the free surface structure are unknown quantities in this model. The unknown free surface is treated explicitly, using a parametric representation with respect to the arc length. The nonlinear problem is discretized by means of a finite element method for the Maxwell's equations and a finite‐difference method for the free surface equations. Numerical modelling allows to get over‐critical equilibrium free surface shapes in a wide range of applied field intensities. Our numerical results show a significant influence of the particle diffusion on the overcritical shapes.

Investigation of Enhancement in Pool Boiling Heat Transfer of a Binary Temperature Sensitive Magnetic Fluid

2013 ◽  
Author(s):  
Giti Karimi-Moghaddam ◽  
Richard D. Gould ◽  
Subhashish Bhattacharya
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Magnetic Fluid ◽  
Boiling Heat Transfer ◽  
Magnetic Particles ◽  
Pool Boiling ◽  
Simulation Software ◽  
Temperature Sensitive ◽  
Magnetic Field Effects ◽  
Pool Boiling Heat Transfer

In this paper, the performance of pool boiling heat transfer using a binary temperature sensitive magnetic fluid in the presence of a non-uniform magnetic field is investigated numerically. By using a binary magnetic fluid, enhanced boiling heat transfer is obtained by thermomagnetic convection without deterioration of properties of the fluid. This work is aimed at gaining a qualitative understanding the magnetic field effects on boiling heat transfer enhancement of magnetic fluids. In order to accomplish this, the boiling process and the effects of position of the external magnetic field on flow pattern and heat transfer are investigated in a 2D rectangular domain using COMSOL Multiphysics simulation software. Finally, the boiling curves for a binary temperature sensitive magnetic fluid and its base fluid (without magnetic particles) are compared for various applied heat flux magnitudes.

A numerical study on the effect of static magnetic field on the hemodynamics of magnetic fluid in biological porous media

2020 ◽  
Vol 141 (5) ◽  
pp. 1543-1558
Author(s):  
Seyed Mahdi Hosseinikhah ◽  
Borhan Beigzadeh ◽  
Majid Siavashi ◽  
Mahdi Halabian
Keyword(s):  
Magnetic Field ◽  
Porous Media ◽  
Static Magnetic Field ◽  
Magnetic Fluid ◽  
Numerical Study

scholarly journals Numerical study of magnetic particles mixing in waste water under an external magnetic field

2020 ◽  
Vol 69 (3) ◽  
pp. 266-275 ◽  
Author(s):  
Christos Liosis ◽  
Evangelos G. Karvelas ◽  
Theodoros Karakasidis ◽  
Ioannis E. Sarris
Keyword(s):  
Magnetic Field ◽  
Magnetic Particles ◽  
Numerical Study ◽  
Low Frequency ◽  
Water And Wastewater Treatment ◽  
Novel Approach ◽  
Optimal Value ◽  
Frequency Optimum ◽  
Combined Action ◽  
Aligned Magnetic Field

Abstract The combination of nanotechnology and microfluidics may offer an effective water and wastewater treatment. A novel approach combines the use of magnetic particles which can capture heavy metal impurities in microfluidic ducts. The purpose of this study is to investigate the mixing mechanism of two water streams, one with magnetic particles and the other with wastewater. The optimum mixing is obtained when particles are uniformly distributed along the volume of water in the duct for the combined action of a permanent, spatially and temporally aligned magnetic field. Results showed that mixing is enhanced as the frequency of the magnetic field decreases or its amplitude increases, while magnetic gradient is found to play an insignificant role in the present configuration. Moreover, for simulations with low frequency, the mean concentration of particles is found to be twice as high as compared to the cases with higher frequency. Optimum distribution of particles inside the micromixer is observed for the combination of 0.6 T, 8 T/m and 5 Hz for the magnetic magnitude, gradient and frequency, respectively, where concentration reaches the optimal value of 0.77 mg/mL along the volume of the duct.

scholarly journals Effect of Magnetic Field and Aggregation on Electrical Characteristics of Magnetically Responsive Suspensions for Novel Hybrid Liquid Capacitor

2019 ◽  
Vol 5 (2) ◽  
pp. 38 ◽  
Author(s):  
Kunio Shimada
Keyword(s):  
Magnetic Field ◽  
Electrical Properties ◽  
Natural Rubber ◽  
Applied Voltage ◽  
Nonlinear Response ◽  
Magnetic Particles ◽  
Particle Aggregation ◽  
Electrical Characteristics ◽  
Rubber Latex ◽  
Wide Range

Magnetically responsive fluid based on polymers of natural rubber (NR-latex) involves a magnetic compound fluid (MCF) rubber liquid. For a wide range of engineering applications of suspensions or liquids with particles, their electrical characteristics of fluidic suspensions are investigated to obtain useful results that might be important in the study of devices, such as fluidic sensors and capacitors. The author of the present paper proposes that MCF rubber liquid can be produced by combining MCF and rubber latex. The influence of the aggregation of magnetic particles and rubber molecules on electrical characteristics under a magnetic field was investigated by measuring electrical properties under an applied voltage. The electrical characteristics change with a linear or a nonlinear response, based on conditions of particle aggregation. The capacity of the electric charge also changes with the conditions of particle aggregation. These results show that MCF rubber liquid is a novel hybrid capacitor.

The Out-Rotator of Spin Traveling Wave Pump on Magnetic Fluid

2012 ◽  
Vol 503 ◽  
pp. 3-7
Author(s):  
Meng Zhao ◽  
Ji Bin Zou ◽  
Jing Shang
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Traveling Wave ◽  
Magnetic Particles ◽  
Theory Method ◽  
The Press ◽  
Relationship Of ◽  
The Relationship ◽  
The Magnetic Field

According to researching the spin traveling wave pump, the relationship of the characteristics of magnetic fluid and the press is investigated under the spin magnetic field by the theory method. The relationship of moving, magnetic field and press is investigated by the decoupled computation between the magnetic field and force. The method is scientificity and rationality by the testing. The distributing shape of magnetic fluid in the pump is affected by the adding magnetic field under the spin magnetic field when the magnetic fluid is filled in the pump. At the same time, the adding magnetic field is affected by magnetic particles of magnetic fluid. The magnetic fluid can be moved by the effect of the adding magnetic field in the pump. The flux of magnetic fluid increases with the magnetic field.

Relation between Dynamic Pressure and Displacement of Free Surface in Two-Layer Sloshing between a Magnetic Fluid and Silicone Oil

2014 ◽  
Vol 792 ◽  
pp. 33-38 ◽  
Author(s):  
Takayoshi Ishiyama ◽  
Shunsuke Kaneko ◽  
Shinichiro Takemoto ◽  
Tatsuo Sawada
Keyword(s):  
Magnetic Field ◽  
Free Surface ◽  
Magnetic Fluid ◽  
Silicone Oil ◽  
Dynamic Pressure ◽  
Pressure Change ◽  
Pressure Transducers ◽  
Presence And Absence

We performed experiments regarding two-layer sloshing, using a magnetic fluid and silicone oil, and measured the dynamic pressure change using pressure transducers. We also investigated displacements of the free surface by comparing it with the dynamic pressure, clarifying the relation between them, both in the presence and absence of a magnetic field.

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