The investigation of simultaneous heat transfer of water/Al2O3 nanofluid in a close enclosure by applying homogeneous magnetic field

Experiments were performed to examine the influence of external homogeneous magnetic field on ferrofluid convection in thin cylindrical layer heated from one wide sidewall and cooled from another. Gravitational and magnetic mechanisms of convection as well as the influence of gravitational sedimentation of particles and their aggregates on stability and structure of fluid flows are studied. The integral and local temperature sensors were used for measurement of heat transport across the layer. Visualization of flow patterns was provided by a temperature-sensitive liquid crystal sheet. The results indicate that with the help of a magnetic field it is possible to control the stability and the form of convection motions. Besides, the concentration gradients of solid phase can have material role to convection instability and heat transfer.

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Gravitational and Magnetic Convection in Magnetic Colloids

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2005-77242 ◽

2005 ◽

Author(s):

Gennady F. Putin ◽

Alexandra A. Bozhko

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Liquid Crystal ◽

Magnetic Particles ◽

Homogeneous Magnetic Field ◽

Temperature Sensors ◽

Localized States ◽

Long Wave ◽

Magnetic Colloids ◽

Magnetic Convection

Experiments were performed to examine the influence of homogeneous magnetic field on convection instability and flows in a layer of magnetic fluid heated from one wide side and cooled from another. The temperature sensors were used for measurement of heat transport across the layer. Visualization of flow patterns was provided by a liquid crystal sheet. The results indicate that with the help of a magnetic field it is possible to control the convection stability, intensity of the heat transfer and the form of convection motions. The interaction of gravitational and magnetic convection mechanisms for different orientations of the layer and magnetic field were studied. The essential influence of gravitational sedimentation of magnetic particles and their aggregates on convection in magnetic colloids is shown. A number of non-linear regimes of convection, including localized states and repeated long-wave transients from convection to conduction were observed.

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On the role of enclosure side walls thickness and heater geometry in heat transfer enhancement of water–Al2O3 nanofluid in presence of a magnetic field

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-019-08224-6 ◽

2019 ◽

Vol 138 (1) ◽

pp. 679-696 ◽

Cited By ~ 13

Author(s):

Seyed Masoud Vahedi ◽

Ahmad Hajatzadeh Pordanjani ◽

Somchai Wongwises ◽

Masoud Afrand

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Heat Transfer Enhancement ◽

Transfer Enhancement ◽

Side Walls ◽

Al2o3 Nanofluid

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Analysis of magneto rheological elastomers for energy harvesting systems

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209350 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 439-446

Author(s):

Gildas Diguet ◽

Gael Sebald ◽

Masami Nakano ◽

Mickaël Lallart ◽

Jean-Yves Cavaillé

Keyword(s):

Magnetic Field ◽

Energy Harvesting ◽

Shear Strain ◽

Magnetic Induction ◽

Magnetic Particles ◽

Homogeneous Magnetic Field ◽

Electrical Signal ◽

Harvesting Systems ◽

Dc Bias ◽

Magneto Rheological

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.

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