Effects of magnetic field on the pool boiling heat transfer of water-based α-Fe_2O_3 and γ-Fe_2O_3 nanofluids

摘要

Pool boiling experiments of water-based alpha-Fe2O3 and gamma-Fe2O3 nanofluids with different concentrations (0.005-0.100 g/L) were conducted at atmospheric pressure. Two kinds of magnetic field induced by two neodymium magnets were also applied to investigate the effects of magnetic field on the pool boiling of nanofluids. It demonstrated that the magnetic field could change the local concentration of nanofluids and produce an extra pressure on the bubble boundary. The extent of the effects was not only dependent on the intensity and distribution of magnetic field, but also the magnetism and concentration of nanoparticles. For the 0.050 gamma-Fe2O3 nanofluid in the presence of magnetic field induced by two mutually exclusive magnets, an enhancement in boiling heat transfer coefficient up to 28% was obtained. The results of the experiments indicated the feasibility to control the pool boiling performance of magnetic nanofluids by external magnetic field. (C) 2018 Elsevier Ltd. All rights reserved.