Experimental study of convective heat transfer in Fe3O4-H2O nanofluids in a grid-shaped micro-channel under magnetic field

Abstract

Experimental study of convective heat transfer with Fe3O4-H2O (1 vol%) nanofluids was examined when the nanofluids flowed through a gridded micro-channel under a perpendicularly oriented magnetic field of 0-700 G strength. The results show that, compared to deionized water, nanofluids reduces chip temperature by 2.11?C and increases the convective heat transfer coefficient by 30.43% when no magnetic field is present. Under magnetic field conditions, the chip temperature was maximally reduced by 3.2?C, while the convective heat transfer coefficient is improved up to 65% in comparison to deionized water. With increasing magnetic field strength, nanofluids pressure drop and flow resistance showed an overall decreasing trend, and the pressure drop at 500 G and 700 G were reduced by 19.3% and 14.51%, respectively, compared to that at 0 G. In terms of overall performance, improved heat transfer in the presence of a magnetic field outper-forms heat transfer in the absence of a magnetic field. The intensive heat transfer factor of nanofluids under magnetic field conditions is greater than one when the Reynolds number exceeds 400. The best overall performance and the highest intensive heat transfer factor are observed at a magnetic field strength of 300 G.