Effect of magnetic field and magnetic nanofluid on heat transmission improvement in a curved minichannel

This study presents an analysis of heat transmission and magnetic nanofluid flow in a minichannel with corrugated upper wall and exposed to a magnetic field. Choice of this geometry allows an improvement of heat transfer contrary to that of rectangular shape. This study is developed to complete the existing ones in the literature. In this two-dimensional study, flow is supposed to be laminar, and the chosen fluid is Fe3O4-water magnetic nanofluid which is used as cooling fluid. For this nanofluid, two volume fractions (0.6, 1%) were used. Several simulations were conducted for a series of Reynolds numbers which vary between 150 and 210 and magnetic field strengths which take values ranging from 0 up to 1400 G for two chosen configurations (a source located at 15 mm and two sources located, respectively, at 7.5 and 15 mm). The results obtained show that magnetic nanofluid subjected to a magnetic field seems as an active vortex generator which modifies the flow structure, allowing a good mixing of the fluid and consequently an improvement in heat transmission. For selected values of magnetic field intensities, an improvement in heat transmission was observed followed by a reduction in pressure drop. This is due to the separation of the fluid from the lower wall which reduces the friction effect. Rise in volume fraction does not modify the flow structure, and it allows an enhancement in heat transfer. According to results obtained, we note a maximum of 10.21% enhancement of heat transmission in the case of a source located at 15 mm and a maximum of 27.44% of improvement of heat transmission in in the case of application of two sources for the case where the volume fraction is equal 1%. With this study, we can locate the correct position of the magnets allowing a good heat transfer rate.

Automated summary

This study presents an analysis of heat transmission and magnetic nanofluid flow in a minichannel with corrugated upper wall and exposed to a magnetic field. The results show that magnetic nanofluid subjected to a magnetic field acts as an active vortex generator, improving fluid mixing and heat transmission. Increase in magnetic field strength and volume fraction has a positive effect on flow structure and heat transfer.