Heat Transfer in Boiling Magnetic Fluid in a Magnetic Field

2015 ◽  
Vol 233-234 ◽  
pp. 339-342 ◽  
Author(s):  
Aleksandr A. Yanovskiy ◽  
Aleksandr Ya. Simonovsky ◽  
Vladimir L. Kholopov ◽  
Irina Yu. Chuenkova
Keyword(s):  
Magnetic Field ◽  
Heat Exchange ◽  
Magnetic Fluid ◽  
Magnetic Field Gradient ◽  
Heating Surface ◽  
Thermal Flow ◽  
Boiling Regime ◽  
Exchange Processes ◽  
Exchange Intensity ◽  
Field Influence

In the present work we report the investigation of heat exchange processes at stationary boiling regime of magnetic fluid on a horizontal surface under magnetic field H ≤ 4.2 kA/m. In the presence of uniform magnetic field the specific thermal flow arriving to boiling magnetic fluid increases by 1.5 - 2 times. We offer the mechanism of magnetic field influence on heat exchange intensity in boiling magnetic fluid. The volume, shape and contact area of steam bubbles in horizontal heating surface in magnetic field is studied. The equation, connecting a specific thermal flow, magnetic field gradient and magnetic fluid magnetization in bubble boiling regime of magnetic fluid is written.

Mechanical Model of Nonmagnetic Mineral Particles in Magneto Hydrostatic Static Separation

2012 ◽  
Vol 233 ◽  
pp. 192-195
Author(s):  
Ying Qiang Zhang ◽  
Jing Tao Wei ◽  
Ting You Wang ◽  
Zhang Yong Wu
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Mechanical Model ◽  
Magnetic Field Gradient ◽  
Equations Of Motion ◽  
Buoyant Force ◽  
Mineral Particles ◽  
Separation Result ◽  
Magnetic Buoyancy ◽  
The Magnetic Field

Base on the fluid dynamics，electromagnetism，Newton’s law and some other basic theories，the paper analyses the equations of motion and Bernoulli for nonmagnetic mineral particles in magnetic fluid. And apply these theories to establish the mechanical model for the nonmagnetic mineral particles in magneto hydrostatic static separation (MHSS). In MHSS, the particles would be stressed by gravity force, magnetic buoyancy, ordinary buoyancy, etc. The wedge-shaped magnetic poles can set up the magnetic buoyancy of which direction is straight up, and the levitation force could be stronger in ferromagnetic fluid. And it can be calculated equating normal buoyant weight to the magnetic buoyant force that any nonmagnetic substance can be floated in magnetic fluid. The paper also analyses some parameters that affect the separation result, such as the magnetic field intensity and the magnetic field gradient. These tasks may give some supports for MHSS applied in industrial.

THE INFLUENCE OF SELECTED FACTORS ON AXIAL FORCE AND FRICTION TORQUE IN A THRUST BEARING LUBRICATED WITH MAGNETORHEOLOGICAL FLUID

Tribologia ◽  
2016 ◽  
Vol 269 (5) ◽  
pp. 51-61 ◽  
Author(s):  
Wojciech HORAK ◽  
Józef SALWIŃSKI ◽  
Marcin SZCZĘCH
Keyword(s):  
Magnetic Field ◽  
Rheological Properties ◽  
Magnetic Fluid ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Magnetic Field Gradient ◽  
Magnetic Fluids ◽  
Carrier Fluid ◽  
Wide Range ◽  
The Magnetic Field

Magnetic fluids belong to the class of materials in which rheological properties can be controlled by magnetic fields. Magnetic fluids are suspensions of ferromagnetic particles in a carrier fluid, and the magnetic field can change their internal structure. This phenomenon is fully reversible, almost instantaneously. The test results of a hydrostatic bearing lubricated by magnetic fluid are shown in the publication [L. 7]. It has been shown that the use of MR fluids as a lubricant allows high stiffness of the bearing to be obtained regardless of the height of the bearing gap. The publication [L. 8] presents the results of a thrust bearing lubricated by magnetic fluid with no external feed pump. The load capacity of the bearing was achieved by a self-sealing effect. This effect is associated with the ability to hold a magnetic fluid in a predetermined position through the magnetic field. This is caused by the appropriate geometry of the bearing surface. This effect retains the flow of the magnetic fluid out of the bearing gap as a result of the occurrence of a magnetic barrier, which counteracts the movement of the magnetic fluid. This barrier is a result of a local increase or decrease in magnetic induction similar to magnetic fluid seals. Another phenomenon highlighted in [L. 9, 10, 11] is the generation in the magnetic fluid of additional pressure due to the interaction of the magnetic field gradient. The result is an additional buoyancy force. When selecting a magnetic fluid for application in the thrust bearing, a number of factors should be taken into account. In addition to the parameters describing the typical lubricant, such as lubricity, corrosion properties, and work at high temperatures, the magnetic fluid used in the friction zone should allow a wide range of the rheological properties to be obtained due to changes in the magnetic field intensity. It is also important that the magnetic fluids have the ability to generate the appropriate value of the normal force due to the magnetic field.

THE UNIFORM MAGNETIC FIELD INFLUENCE ON THE MAGNETIC FLUID MENISCUS MOTION IN THE CYLINDRICAL CAPILLARY

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2590-2596 ◽  
Author(s):  
V. BASHTOVOI ◽  
P. KUZHIR ◽  
A. REKS ◽  
G. BOSSIS ◽  
O. VOLKOVA
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Uniform Magnetic Field ◽  
Transverse Field ◽  
Experimental Investigations ◽  
Zero Gravity ◽  
Liquid Penetration ◽  
Field Influence ◽  
External Uniform Magnetic Field ◽  
Wetting Liquid

An improvement of liophobic capillary-porous systems using magnetic fluids is proposed. The cycle of non-wetting liquid penetration and displacement is realized experimentally in the presence of the uniform magnetic field. Experimental investigations of the effect of the external uniform magnetic field on dynamics of capillary penetration of the Newtonian magnetic fluid into cylindrical capillaries at zero gravity and under gravity are presented. It is found that the pressure difference in the magnetic fluid between a meniscus and a free surface in a vessel increases in the field longitudinal to the capillary and decreases in the transverse one. In the longitudinal field, the velocity of penetration increases at zero gravity and does not vary under gravity. The transverse field slows down the process.

Spectroscopic imaging of human disease

1996 ◽  
Vol 54 ◽  
pp. 884-885
Author(s):  
D.J. Meyerhoff
Keyword(s):  
Magnetic Field ◽  
Magnetic Resonance ◽  
Field Gradient ◽  
Human Disease ◽  
Morphological Changes ◽  
Magnetic Field Gradient ◽  
Spectroscopic Imaging ◽  
Resonance Spectroscopy ◽  
Tissue Water

Magnetic Resonance Imaging (MRI) observes tissue water in the presence of a magnetic field gradient to study morphological changes such as tissue volume loss and signal hyperintensities in human disease. These changes are mostly non-specific and do not appear to be correlated with the range of severity of a certain disease. In contrast, Magnetic Resonance Spectroscopy (MRS), which measures many different chemicals and tissue metabolites in the millimolar concentration range in the absence of a magnetic field gradient, has been shown to reveal characteristic metabolite patterns which are often correlated with the severity of a disease. In-vivo MRS studies are performed on widely available MRI scanners without any “sample preparation” or invasive procedures and are therefore widely used in clinical research. Hydrogen (H) MRS and MR Spectroscopic Imaging (MRSI, conceptionally a combination of MRI and MRS) measure N-acetylaspartate (a putative marker of neurons), creatine-containing metabolites (involved in energy processes in the cell), choline-containing metabolites (involved in membrane metabolism and, possibly, inflammatory processes),

Increase of Heat Exchange Processes Efficiency at Production Site

2017 ◽  
pp. 18-21
Author(s):  
A.F. Khasanova ◽  
◽  
M.A. Gallyamov ◽  
Z.A. Zakirova ◽  
◽  
...  
Keyword(s):  
Heat Exchange ◽  
Production Site ◽  
Exchange Processes

Physical Interpretations of Internal Magnetic Field Influence on Processes in Tribocontact of Textured Dimple Surfaces

2019 ◽  
Vol 11 (5) ◽  
pp. 05013-1-05013-5
Author(s):  
V. Ye. Marchuk ◽  
◽  
M. V. Kindrachuk ◽  
V. I. Mirnenko ◽  
R. G. Mnatsakanov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Internal Magnetic Field ◽  
Field Influence
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