Effects of magnetic field on the pool boiling heat transfer of water-based α-Fe2O3 and γ-Fe2O3 nanofluids

Pool boiling experiments of water-based α-Fe2O3 and γ-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 g/L γ-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.