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ferrofluid
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An experimental study on the effect of ultrasonication on thermal conductivity of ferrofluid loaded with carbon nanotubes
, Article Thermochimica Acta ; Volume 617 , October , 2015 , Pages 102-110 ; 00406031 (ISSN) ; Salimpour, M. R ; Saghafian, M ; Shafii, M. B ; Sharif University of Technology
Elsevier
2015
Abstract
Nanofluids containing Fe3 O4 and carbon nanotubes nanoparticles emulsified and dispersed using gum arabic (GA) and tetramethylammonium hydroxide (TMAH) were made and characterized for potential use as heat transfer fluids. Due to the interaction between the TMAH and GA molecules, the magnetic nanoparticles and CNTs were physically adsorbed. This paper reports an experimental work on the effect of ultrasonication on thermal conductivity of this aqueous suspension. The characterization and surface morphology of the dried samples were studied by using XRD and TEM measurements. Experiments were conducted in the magnetic nanoparticles mass concentration range 0.494-2.428%,...
Study the effect of ultrasonic irradiation and surfactant/fe ions weight ratio on morphology and particle size of magnetite nanoparticles synthesised by co-precipitation for medical application
, Article World Academy of Science, Engineering and Technology ; Volume 64 , 2010 , Pages 457-460 ; 2010376X (ISSN) ; Pourafshary, P ; Madaah Hosseini, H. R ; Sharif University of Technology
2010
Abstract
A biocompatible ferrofluid have been prepared by coprecipitation of FeCl 2.4H 2O and FeCl 3.6H 2O under ultrasonic irradiation and with NaOH as alkaline agent. Cystein was also used as capping agent in the solution. Magnetic properties of the produced ferrofluid were then determined by VSM test and magnetite nanoparticles were characterized by XRD and TEM techniques. The effect of surfactant to Fe ion weight ratio was also studied during this project by using two different amount of Dextran. Results showed the presence of a biocompatible superparamagnetic ferrofluid including magnetite nanoparticles with particle size ranging under 20 nm. The increase in the surfactant content results in the...
Effect of magnetic field on internal forced convection of ferrofluid flow in porous media
, Article Experimental Heat Transfer ; Volume 29, Issue 1 , 2016 , Pages 1-16 ; 08916152 (ISSN) ; Sehat, A ; Shafii, M. B ; Sharif University of Technology
Taylor and Francis Ltd
Abstract
Enhancement of heat transfer is investigated in an experimental study of ferrofluid flow in a tube subjected to a constant and uniform heat flux on its wall, filled with permeable material under the effect of magnetic field. Effect of ferrofluid volume fraction, Reynolds number, and different frequencies of various magnetic field modes on heat transfer is examined by measuring the temperature on the wall. Using ferrofluid under the effect of magnetic field improves the heat transfer, and porous media makes the temperature distribution more uniform. Volumetric percentage of nano-particles has the greatest effect on the heat transfer
Numerical simulation of magnetic convection ferrofluid flow in a permanent magnet–inserted cavity
, Article Journal of Magnetism and Magnetic Materials ; Volume 442 , 2017 , Pages 270-278 ; 03048853 (ISSN) ; Behshad Shafii, M ; Sharif University of Technology
Abstract
The magnetic convection heat transfer in an obstructed two-dimensional square cavity is investigated numerically. The walls of the cavity are heated with different constant temperatures at two sides, and isolated at two other sides. The cavity is filled with a high Prandtl number ferrofluid. The convective force is induced by a magnetic field gradient of a thermally insulated square permanent magnet located at the center of the cavity. The results are presented in the forms of streamlines, isotherms, and Nusselt number for various values of magnetic Rayleigh numbers and permanent magnet size. Two major circulations are generated in the cavity, clockwise flow in the upper half and...
Visualization and comparative investigations of pulsating ferro-fluid heat pipe
, Article Applied Thermal Engineering ; Volume 116 , 2017 , Pages 56-65 ; 13594311 (ISSN) ; Saidi, M. H ; Shafii, M. B ; Vandadi, M ; Kalan, K ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Pulsating heat pipes (PHPs) are among the best solutions for the electronics cooling due to their low cost, effectiveness and being passive. Experiments to study the effective factors on heat transfer performance have been designed and as a result, improvement of ferrofluid PHP performance has been achieved. Two different heat pipes made of copper and glass were prepared to investigate the behavior of magnetic nanofluids. In order to find the best condition for heat transfer performance, different concentrations of nanofluid with a filling ratio of 50% were tested in 3 different cases of magnetic field. The results indicated that the ferrofluid is more stable in the glass PHP. It also shows...
Numerical investigation on splitting of ferrofluid microdroplets in T-junctions using an asymmetric magnetic field with proposed correlation
, Article Journal of Magnetism and Magnetic Materials ; Volume 447 , February , 2018 , Pages 139-149 ; 03048853 (ISSN) ; Bijarchi, M. A ; Shafii, M. B ; Kazemzadeh Hannani, S ; Sharif University of Technology
Elsevier B.V
2018
Abstract
The studies surrounding the concept of microdroplets have seen a dramatic increase in recent years. Microdroplets have applications in different fields such as chemical synthesis, biology, separation processes and micro-pumps. This study numerically investigates the effect of different parameters such as Capillary number, Length of droplets, and Magnetic Bond number on the splitting process of ferrofluid microdroplets in symmetric T-junctions using an asymmetric magnetic field. The use of said field that is applied asymmetrically to the T-junction center helps us control the splitting of ferrofluid microdroplets. During the process of numerical simulation, a magnetic field with various...
Ferrofluid droplet formation from a nozzle using alternating magnetic field with different magnetic coil positions
, Article Journal of Magnetism and Magnetic Materials ; Volume 498 , 2020 ; Bijarchi, M. A ; Shafii, M. B ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Ferrofluid has been used in many fields, such as microfluidics, droplet formation, and heat transfer, due to its potential to be attracted in the presence of a magnetic field. Droplet formation, itself, has many applications such as emulsions, 3D micro-printers, MEMS, and electro-sprays. In this study, the mechanism of ferrofluid droplet formation from the nozzle in the presence of an alternating magnetic field was investigated. The magnetic coil was fixed at different angles with respect to gravity and the effect of the alternating magnetic field and the angle of the magnetic coil axis with respect to gravity on the produced droplet volume, satellite droplet, and droplet formation frequency...
Heat transfer enhancement of ferrofluid flow within a wavy channel by applying a non-uniform magnetic field
, Article Journal of Thermal Analysis and Calorimetry ; Volume 139, Issue 5 , 2020 , Pages 3331-3343 ; Biglarian, M ; Rabienataj Darzi, A. A ; Farhadi, M ; Hassanzadeh Afrouzi, H ; Toghraie, D ; Sharif University of Technology
Springer Netherlands
2020
Abstract
This paper presents the effects of a non-uniform magnetic field on the hydrodynamic and thermal behavior of ferrofluid flow in a wavy channel by 3D numerical simulation. The wavy surfaces at the top and bottom of the channel are heated by constant heat fluxes. Moreover, the sidewalls are adiabatic. In the wavy section, in the perpendicular direction of the main flow, the magnetic field that linearly varies along the direction of the main flow is applied. The mathematical model that is consistent with the principles of ferrohydrodynamics and magnetohydrodynamics is used for the problem formulation. The results indicate that the wavy wall enhances the heat transfer rate on the bottom of the...
Numerical investigation on the effect of external varying magnetic field on the mixing of ferrofluid with deionized water inside a microchannel for lab-on-chip systems
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; 2020 ; Ghassemi, M ; Shafii, M. B ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
Energy-efficient mixing is vital for chemical and fuel processes. To this end, a flow-focusing configuration is proposed to investigate the effect of a uniform magnetic field on the mixing of a water-based ferrofluid with two streams of deionized water. An external and varying magnetic field is imposed on a straight microchannel, and the mixing between the ferrofluid and deionized waters is qualitatively and quantitatively measured. A commercial code based on the finite-element method is used, and the simulations are validated by two experimental studies in the literature. For a magnetic flux density of 10 mT, a signal frequency of 1 Hz, a duty cycle of 0.3, an inlet velocity of 500 µm/s,...
The effect of non-uniform magnetic field on the efficiency of mixing in droplet-based microfluidics: a numerical investigation
, Article Micromachines ; Volume 13, Issue 10 , 2022 ; 2072666X (ISSN) ; Nouri, M ; Hassani Gangaraj, M ; Shamloo, A ; Nasiri, R ; Sharif University of Technology
MDPI
2022
Abstract
Achieving high efficiency and throughput in droplet-based mixing over a small characteristic length, such as microfluidic channels, is one of the crucial parameters in Lab-on-a-Chip (LOC) applications. One solution to achieve efficient mixing is to use active mixers in which an external power source is utilized to mix two fluids. One of these active methods is magnetic micromixers using ferrofluid. In this technique, magnetic nanoparticles are used to make one phase responsive to magnetic force, and then by applying a magnetic field, two fluid phases, one of which is magneto-responsive, will sufficiently mix. In this study, we investigated the effect of the magnetic field’s characteristics...
Experimental and Numerical Investigation on the Single Drop Liquid-liquid Mass Transfer in the Presence of Magnetic Nano-particles (Ferrofluids) and Magnetic Field
, Ph.D. Dissertation Sharif University of Technology ; Molaie Dehkordi, Asghar (Supervisor) ; Seif Kordi, Ali Akbar (Co-Supervisor)
Abstract
The main objective of the present work was to improve the turbulence in single drops using ferrofluids (magnetic nanoparticles) in the presence of uniform and oscillating magnetic fields. In this regard, magnetite nanoparticles ($\mathrm{Fe_3O_4}$) were synthesized by co-precipitation method, characterized using DLS, FT-IR, XRD, VSM, and TEM, and their stability was checked by UV-Vis. The obtained results indicate the proper synthesis of nanoparticles with a mean diameter of about 20 nm and by coating their surfaces by silane that were well stabilized in the base fluid. In the numerical section, the governing equations of transport phenomena for a single drop containing magnetic fluids were...
Experimental and Numerical Investigation on the Splitting of Microdroplets in Symmetrical and Asymmetrical T Junctions Using Magnetic Fields
, Ph.D. Dissertation Sharif University of Technology ; Shafii, Mohammad Behashad (Supervisor) ; Kazemzadeh Hannani, Siamak (Co-Supervisor)
Abstract
Ferrofluids are used in various fields such as drug delivery systems, heat transfer, biotechnology and separation processes. In this study, the splitting of ferrofluid microdroplets in symmetric and asymmetric T-junctions in the presence of a magnetic field has been investigated numerically and experimentally. These studies have shown that the creation of an asymmetric magnetic field can either affect the phenomenon of ferrofluid microdroplet breakup or the volume of microdroplets that are created after breaking and leaving each branch. Furthermore, more control can be applied to the phenomenon of microdroplet breakup. In the numerical study, the ferrofluid microdroplet breakup at different...
Experimental investigation on laminar forced convection heat transfer of ferrofluids under an alternating magnetic field
, Article Experimental Thermal and Fluid Science ; Volume 49 , 2013 , Pages 193-200 ; 08941777 (ISSN) ; Dibaei, M. H ; Hakim Sima, A ; Shafii, M. B ; Sharif University of Technology
2013
Abstract
This research study presents an experimental investigation on forced convection heat transfer of an aqueous ferrofluid flow passing through a circular copper tube in the presence of an alternating magnetic field. The flow passes through the tube under a uniform heat flux and laminar flow conditions. The primary objective was to intensify the particle migration and disturbance of the boundary layer by utilizing the magnetic field effect on the nanoparticles for more heat transfer enhancement. Complicated convection regimes caused by interactions between magnetic nanoparticles under various conditions were studied. The process of heat transfer was examined with different volume concentrations...
Experimental investigation of an open loop pulsating heat pipe using ferrofluid
, Article ASME 2012 3rd International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2012 ; 2012 , Pages 175-184 ; 9780791854778 (ISBN) ; Taslimifar, M ; Saidi, M. H ; Shafii, M. B ; Afshin, H ; Saimak, K. H ; Sharif University of Technology
Abstract
The present work investigates the thermal performance of a five turn Open Loop Pulsating Heat Pipe (OLPHP). The effects of working fluid namely water and ferrofluid, heat input, ferrofluid concentration, charging ratio, and orientation will be considered. Experimental results show that using ferrofluids can enhance the thermal performance in comparison with the case of distilled water. In addition, applying a magnetic field on the OLPHP charged with ferrofluid reduces its thermal resistance. Variation of the ferrofluid concentration results in different thermal performance of the OLPHP. Best charging ratio for the distilled water and ferrofluid without magnetic field is 60 % in most of the...
Effects of surface coating of nanoparticles on thermal performance of Open Loop Pulsating Heat Pipes
, Article ASME 2012 Heat Transfer Summer Conf. Collocated with the ASME 2012 Fluids Engineering Div. Summer Meeting and the ASME 2012 10th Int. Conf. on Nanochannels, Microchannels and Minichannels, HT 2012, 8 July 2012 through 12 July 2012 ; Volume 2 , 2012 , Pages 593-599 ; 9780791844786 (ISBN) ; Maziar, M ; Ali, A ; Hossein, A ; Mohammad Hassan, S ; Mohammad Behshad, S ; Siamak, K. H ; Sharif University of Technology
2012
Abstract
Homogenous dispersing of nanoparticles in a base fluid is an excellent way to increase the thermal performance of heat transfer devices especially Heat Pipes (HPs). As a wickless, cheap and efficient heat pipe, Pulsating Heat Pipes (PHPs) are important candidates for thermal application considerations. In the present research an Open Loop Pulsating Heat Pipe (OLPHP) is fabricated and tested experimentally. The effects of working fluid namely, water, Silica Coated ferrofluid (SC ferrofluid), and ferrofluid without surface coating of nanoparticles (ferrofluid), charging ratio, heat input, and application of magnetic field on the overall thermal performance of the OLPHPs are investigated....
Experimental investigation into laminar forced convective heat transfer of ferrofluids under constant and oscillating magnetic field with different magnetic field arrangements and oscillation modes
, Article Experimental Thermal and Fluid Science ; Volume 68 , November , 2015 , Pages 601-611 ; 08941777 (ISSN) ; Moazami Goudarzi, H ; Shafii, M. B ; Sharif University of Technology
Elsevier Inc
2015
Abstract
In this study, the effects of ferrofluids on the forced convective heat transfer in a tube with a round cross section under constant heat flux in the laminar flow regime are investigated experimentally. For this purpose, an experimental setup was designed and built. Furthermore, the effects of an external magnetic field on the forced convective heat transfer were examined for various Reynolds numbers and volume concentrations. The parameters of magnetic field strength, magnetic field arrangement, the constancy or oscillation of the magnetic field and also its oscillatory mode were examined. As a result of the experimental studies, in the absence of a magnetic field enhancement in convective...
Thermal Conductivity of Fe2O3 and Fe3O4 Magnetic Nanofluids Under the Influence of Magnetic Field
, Article International Journal of Thermophysics ; Volume 36, Issue 10-11 , September , 2015 , Pages 2720-2739 ; 0195928X (ISSN) ; Goharkhah, M ; Ashjaee, M ; Shafii, M. B ; Sharif University of Technology
Springer New York LLC
2015
Abstract
In this paper, the thermal conductivity of water-based hematite Fe2O3 and magnetite Fe3O4 nanofluids have been investigated in the absence and presence of a uniform magnetic field. The experiments have been performed in the volume concentration range of 0 % to 4.8 % and the temperature range of 20∘C to 60∘C. The effects of the particle volume fraction, temperature, and magnetic field strength on the thermal conductivity have been analyzed. Results show that the thermal conductivity of iron oxide nanofluids has a direct relation with the particle volume fraction and temperature, without the presence of a magnetic field. But surprisingly, when the magnetic field is applied, it is observed that...
Synthesis and analysis of the properties of ferro-fluids
, Article ICONN 2010 - Proceedings of the 2010 International Conference on Nanoscience and Nanotechnology, 22 February 2010 through 26 February 2010, Sydney, NSW ; 2010 , Pages 91-93 ; 9781424452620 (ISBN) ; Ghane Motlagh, B ; Ghane Golmohamadi, F ; Ghane Motlagh, R ; Rouhani, S ; Sharif University of Technology
2010
Abstract
We report the rheological properties of ferro-fluid (FF) containing iron oxide nano-particles. At first, a FF was synthesized by using chemical co-precipitaton[1]. The microstructure study using SEM revealed that the FF contained nano-particles with the mean particle size of 35nm. The XRD study revealed that we have well crystallized structures of magnetite; they appeared to be approximately single crystalline structures. The rheological results proved that the FF has non Newtonian behavior, it is a shear thinning fluid in all magnetic fields, Moreover, the magnetic field increases the viscosity in a definite shear rate due to the nano-particles agglomerations and formation of chain-like...
Effect of magnetic field on thermal conductivity and viscosity of a magnetic nanofluid loaded with carbon nanotubes
, Article Journal of Mechanical Science and Technology ; Volume 30, Issue 2 , 2016 , Pages 809-815 ; 1738494X (ISSN) ; Salim Pour, M. R ; Saghafian, M ; Shafii, M. B ; Sharif University of Technology
Korean Society of Mechanical Engineers
Abstract
The present work examines experimentally the effect of magnetic field on the viscosity and thermal conductivity of a hybrid nanofluid containing tetramethylammonium hydroxide (TMAH) coated Fe3O4 nanoparticles and Gum arabic (GA) coated carbon nanotubes (CNTs). The hybrid nanofluid was prepared by using ultrasonic dispersion method. Magnetic field was created by a pair of spaced apart magnet plates. The effect of temperature on the time variation of thermal conductivity under applied magnetic field was also investigated. According to the results of this study, viscosity of the hybrid nanofluid increases with the strength of magnetic field, while it decreases with the increase of temperature....
Effect of non-uniform magnetic field on heat transfer of swirling ferrofluid flow inside tube with twisted tapes
, Article Chemical Engineering and Processing: Process Intensification ; Volume 117 , 2017 , Pages 70-79 ; 02552701 (ISSN) ; Hariri, S ; Barzegar Gerdroodbary, M ; Yeganeh, R ; Sharif University of Technology
Abstract
In this article, a three-dimensional numerical simulation is performed to investigate the effect of magnetic field on the heat transfer of ferrofluid inside a tube which is equipped with twisted tape. This work comprehensively focused on the flow feature and temperature distribution of ferrofluid in presence of non-uniform magnetic field while ferrofluid swirled inside a tube with twisted tape. In this study, it is assumed that the ferrofluid is single phase and laminar and constant heat flux is applied on the outside of the tube. The magnetic field is established by wire in parallel direction with the axis of the tube. The base fluid is water with 0.86 Vol% Nano particles (Fe3O4). The...