Effect of magnetic Field on Natural Convection Heat Transfer in Nanofluids.

Nanofluid samples

The potential of nano-particle suspensions in heat transfer rate alteration is now evident from the research carried out for the past two decades. The enhanced thermal conductivity, non-clogging and non-erosive property of nanofluids have made them an alternative for existing coolants. But, heat transfer in nanofluids can be influenced by the presence of magnetic fields in cooling applications like MRI, Nuclear Power Plant. In order to understand the effect of uniform magnetic field on heat transfer in Natural Convection of nanofluids, experimental investigation has been carried out. Electrically conducting/insulating, magnetic/non-magnetic nano-particles are dispersed in base fluid to study the effect of magnetic field. To study the shape and volume effect; tubular, spherical and flake type nano-particles are used in preparing nanofluids. Multi Wall Carbon Nano Tube( tubular, electrically conducting, non-magnetic particles), Silica(spherical, electrically insulating, non-magnetic), Copper(spherical, electrically conducting, non-magnetic), Graphene (flake, electrically conducting, non-magnetic) nanofluid etc. have been tested. The study includes effect of direction, strength of magnetic field and volume fraction of nanofluid. A depreciation in heat transfer is observed only in the case of electrically conducting nanofluid while, there is no change in the case of electrically non-conducting nanofluid. Therefore, use of electrically conducting nanofluids in an application where it can be influenced by magnetic field will produce detrimental effect on heat transfer.