The Preparation and Thermal Conductivities Enhacement of Nanofluids Containing Graphene Oxide Nanosheets

The work presents a method to prepare stable nanofluids containing graphene oxide nanosheets (GO-EG nanofluid). The hydrophilic surfaces let graphene oxide nanosheets have good compatibility with ethylene glycol. The thermal conductivity of the nanofluids was measured by a short hot wire technique, and the result shows that the thermal conductivity of GO-EG nanofluids is almost constant within 7 days, and it reflects the high stability of GO-EG nanofluids. The thermal conductivity enhancement ratios of GO-EG nanofluids were almost constant with tested temperatures vary. GO-EG nanofluids have substantially higher thermal conductivities than the base fluids. When the loading is 5.0 vol.%, the enhancement ratios is up to 61%, much larger than those of metallic oxide. For 1.0 vol.% GO-EG nanofluid, the enhancement ratios is 10.5%, less than those of CNT with the same loading. The reason may be due to the defects, caused by the treatment with strong Oxidants. In our opinion, heat transport in the GO nanosheet is one of the major contributions to the increase of the effective thermal conductivity of nanofluids.