Forced convection of a temperature-sensitive ferrofluid in presence of magnetic field of electrical current-carrying wire: A two-phase approach

Hangi, Morteza; Bahiraei, Mehdi; Rahbari, Alireza

doi:10.1016/j.apt.2018.05.026

Cited by 36 publications

(2 citation statements)

References 34 publications

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“…It should be noted that such an increase is in any case unusual for this class of surfactant stabilized colloids. We can refer to other papers dealing with tetradecane based ferrofluids stabilized by oleic acid, where values of η F F = 6 • 10 −3 Pa.s [70] and η F F = 7 • 10 −3 Pa.s [71] were given. An increase by an order of magnitude of colloid viscosity relative to that of carrier fluid has been observed at Φ = 1.5% in electrostatically aqueous ferrofluids based on hydroxyl-coated NPs with an identified structure of "Sols of clusters" [72].…”

Section: Viscosimetrymentioning

confidence: 99%

Effect of an excess of surfactant on thermophoresis, mass diffusion and viscosity in an oily surfactant-stabilized ferrofluid

et al. 2022

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Section: Viscosimetrymentioning

confidence: 99%

Effect of an excess of surfactant on thermophoresis, mass diffusion and viscosity in an oily surfactant-stabilized ferrofluid

et al. 2022

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“…Using mixture model and the finite volume method, they concluded that the rate of heat transfer increased by increasing the wavy channel amplitude, ferrofluid volume fraction and Reynolds number. Applying two-phase mixture model, Hangi et al (2018) examined the convective heat transfer of a temperature-sensitive ferrofluid flowing in a horizontal tube. Significant heat transfer augmentation of 34.5% was observed in the presence of two wires located at the top and bottom of the tube.…”

Section: Introductionmentioning

confidence: 99%

A comparative analysis on the single-phase and two-phase mixture models for calculation of ferrofluid convective heat transfer in the presence of a magnetic field: a numerical study

Jafari¹,

Goharkhah²,

Nejad³

2021

HFF

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Purpose This paper aims to analyze the accuracy of the single and two-phase numerical methods for calculation of ferrofluid convective heat transfer in the presence of a magnetic field. The findings of current study are compared with previous single-phase numerical results and experimental data. Accordingly, the effect of various parameters including nanoparticles concentration, Reynolds number and magnetic field strength on the performance of the single and two-phase models are evaluated. Design/methodology/approach A two-phase mixture numerical study is carried out to investigate the influence of four U-shaped electromagnets on the hydrodynamic and thermal characteristics of Fe3O4/Water ferrofluid flowing inside a heated channel. Findings It is observed that the applied external magnetic field signifies the convective heat transfer from the channel surface, despite local reduction at a few locations. The maximum heat transfer enhancement is predicted as 23% and 25% using single and two-phase models, respectively. The difference between the results of the two models is mainly attributed to the slip velocity effect which is accounted for in the two-phase model. The magnetic field gradient leads to a significant increase in the slip velocity which in turn causes a slight difference in velocity and temperature profiles obtained by the single and two-phase models in the magnetic field region. According to percentage error calculation, the two-phase method is generally more accurate than the single-phase method. However, the percentage error of both models improves by decreasing either magnetic field intensity or Reynolds number. Originality/value For the first time in the literature, to the best of the authors’ knowledge, the current work analyzes the accuracy of the single and two phase numerical methods for calculation of ferrofluid convective heat transfer in the presence of a magnetic field.

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Hydro - thermal interactions of a ferrofluid in a non - uniform magnetic field

2022

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A numerical study is performed to examine the influence of a non-uniform magnetic field on the thermo-hydraulic behaviour of a ferrofluid. The analysis is done in the context of a differentially heated semi-circular annulus where a magnetic dipole with its distinct location and dipole strength is used to obtain different configurations. The field variables are computed by solving the coupled set of flow equations, energy equations and the Maxwell’s magneto-statics equations. A detailed description is provided on the flow and thermal response after observing different parameters at both global and local scale. Comparison of streamlines and isotherms with a reference case of natural convection concludes that the recirculation zones are responsible for the increased velocity and heat transfer magnitudes. Another key finding of the present work is about the possibility to locally improve the thermal performance of heat exchangers at any desired position along the circumference.

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Forced convection of a temperature-sensitive ferrofluid in presence of magnetic field of electrical current-carrying wire: A two-phase approach

Cited by 36 publications

References 34 publications

Effect of an excess of surfactant on thermophoresis, mass diffusion and viscosity in an oily surfactant-stabilized ferrofluid

Effect of an excess of surfactant on thermophoresis, mass diffusion and viscosity in an oily surfactant-stabilized ferrofluid

A comparative analysis on the single-phase and two-phase mixture models for calculation of ferrofluid convective heat transfer in the presence of a magnetic field: a numerical study

Hydro - thermal interactions of a ferrofluid in a non - uniform magnetic field

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