Mohammad ghoharkhah; Behzad Alizadeh
Volume 13, Issue 4 , December 2020, , Pages 59-69
Abstract
In this numerical study, effect of magnetic field on the convective heat transfer of a magnetic fluid in an enclosure is investigated in the microgravity condition. Two cases of a single magnetic field source under the enclosure and two sources on the top and below the enclosure are considered and the ...
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In this numerical study, effect of magnetic field on the convective heat transfer of a magnetic fluid in an enclosure is investigated in the microgravity condition. Two cases of a single magnetic field source under the enclosure and two sources on the top and below the enclosure are considered and the simulations are carried out for different magnetic field intensities and magnetic source distances from the enclosure. Results indicate that the heat transfer in the microgravity is much lower than that of natural condition due to the lack of the flow vortex. Applying the magnetic field and the induced vortex due to the magnetic body force cause a significant improvement of the heat transfer. Results show that the heat transfer rate in the microgravity condition can be increases up to 6.5 times. Moreover, placing two magnetic field sources improves the main vortex and leads to 19.7 times enhancement of the heat transfer rate compared to the case of single source.
Mohmmad Goharkhah; Mostafa Esmaeili; Mehdi Ashjaee
Volume 11, Issue 2 , September 2018, , Pages 11-19
Abstract
In this paper, the effect of an external non-uniform magnetic field on forced convective heat transfer of magnetite nanofluid (ferrofluid) in a heated channel is studied numerically. The main goal is to emphasize the importance of magnetic field location and investigate the possibility of heat transfer ...
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In this paper, the effect of an external non-uniform magnetic field on forced convective heat transfer of magnetite nanofluid (ferrofluid) in a heated channel is studied numerically. The main goal is to emphasize the importance of magnetic field location and investigate the possibility of heat transfer enhancement by finding the optimum location of magnetic field source.It is observed that the magnetic field results in creation of recirculation zones which affect the thermal boundary layer thickness and Nusselt number. Results show that the effect of magnetic field location on the heat transfer is completely dependent on the thermal boundary condition. It is also shown that the flow and temperature fields can be manipulated by application of multiple magnetic field sources. Using genetic algorithm (GA), an optimum arrangement for locations of eight magnetic field sources is obtainedresulting in a27% heat transfer enhancement compared to the case of no magnetic field.
