Application of electromagnets for forced convective heat transfer enhancement of magnetic fluids

Jafari, Hamed; Goharkhah, Mohammad

doi:10.1016/j.ijthermalsci.2020.106495

Cited by 19 publications

(15 citation statements)

References 28 publications

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“…A set of numerical simulations are performed at three different values of ferrofluid volume fraction, (ϕ=1%,1.5%,2%), six values of Reynolds number (Re = 200–1200) and two values of magnetic flux density (B = 300G, 500 G). The obtained mixture model results are compared with the results of the single-phase homogeneous model (Jafari and Goharkhah, 2020) and experimental data (Goharkhah et al , 2015). In the following, the magnetic field distribution and mechanism of the magnetic field influence on the ferrofluid is describes first.…”

Section: Resultsmentioning

confidence: 99%

“…The average heat transfer coefficient calculated by the single (Jafari and Goharkhah, 2020) and two-phase models along with the experimental results (Goharkhah et al , 2015) are summarized in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…Thermal conductivity of the nanofluid in the absence and presence of the magnetic field is obtained from equations 16 and 17, respectively (Jafari and Goharkhah, 2020; Karimi et al , 2016): where the base fluid and nanoparticle are referred by f and p , respectively and φ is the volumetric concentration of the nanoparticles. The thermophysical properties of the ferrofluid depend on those of the nanoparticles and base fluid.…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…The properties of the magnetite nanoparticles are assumed constant while those of the base-fluid (i.e. water) are temperature-dependent (Jafari and Goharkhah, 2020).…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…It acted like an obstacle that disturbed the flow field and the thermal boundary layer. Jafari and Goharkhah studied (Jafari and Goharkhah, 2020) the same problem numerically. They calculated the velocity and temperature distributions in the channel under the effect of different magnetic field intensities.…”

Section: Introductionmentioning

confidence: 99%

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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

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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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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Mathematical Formulationmentioning

confidence: 99%

“…The properties of the magnetite nanoparticles are assumed constant while those of the base-fluid (i.e. water) are temperature-dependent (Jafari and Goharkhah, 2020).…”

Section: Mathematical Formulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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