Showing papers by "Huaqing Xie published in 2010"
TL;DR: In this article, carbon nanotubes (CNTs) were treated by mechano-chemical reaction with ball milling the mixture of potassium hydroxide and pristine CNTs.
321 citations
TL;DR: The measurements of thermal conductivity indicate that the stable ethylene-glycol-based nanofluids containing graphene oxide nanosheets have substantially higher thermal conductivities than the base fluid.
Abstract: Stable ethylene-glycol-based nanofluids containing graphene oxide nanosheets have been prepared. The measurements of thermal conductivity indicate that the nanofluids have substantially higher thermal conductivities than the base fluid. The thermal conductivity enhancement depends strongly on the volume fraction of graphene oxide nanosheets and increases with the increasing loading. When the nanosheet loading is 5.0 vol%, the enhancement ratio is up to 61.0%. The thermal conductivity of the fluids remains almost constant for seven days, indicating their high stability. The level of enhancement is independent of temperature in the measured temperature range.
203 citations
TL;DR: In this article, the thermal conductivity enhancement ratio of nanofluids containing graphene oxide nanosheets has been shown to be almost constant with the tested temperature varying, and they are reduced with the increasing thermal conductivities of the base fluids.
Abstract: Nanofluids containing graphene oxide nanosheets have substantially higher thermal conductivities than the base fluids. The thermal conductivity enhancement ratios with the loading 5.0 vol % are up to 30.2%, 62.3%, and 76.8%, when the base fluids are distilled water, propyl glycol and liquid paraffin, respectively. The enhancement ratios of the nanofluids are almost constant with the tested temperature varying, and they are reduced with the increasing thermal conductivity of the base fluids. Heat transport along the graphene oxide plane is proposed to be the major contributions to the increase in the thermal conductivity.
157 citations
TL;DR: In this article, stable ethylene glycol-based copper nanofluids were prepared through a two-step method, using polyvinyl pyrrolidone as dispersant.
143 citations
TL;DR: Homogeneous and stable magnetic nanofluids containing γ-Fe2O3 nanoparticles were prepared using a two-step method, and their thermal transport properties were investigated.
Abstract: Homogeneous and stable magnetic nanofluids containing γ-Fe2O3 nanoparticles were prepared using a two-step method, and their thermal transport properties were investigated. Thermal conductivities of the nanofluids were measured to be higher than that of base fluid, and the enhanced values increase with the volume fraction of the nanoparticles. Viscosity measurements showed that the nanofluids demonstrated Newtonian behavior and the viscosity of the nanofluids depended strongly on the tested temperatures and the nanoparticles loadings. Convective heat transfer coefficients tested in a laminar flow showed that the coefficients increased with the augment of Reynolds number and the volume fraction.
79 citations
TL;DR: In this paper, the authors investigated the convective heat transfer enhancement of nanofluids as coolants in laminar flows inside a circular copper tube with constant wall temperature.
70 citations
TL;DR: In this paper, phase change nanocomposites were prepared by dispersing γ-Al2O3 nanoparticles into melting paraffin wax (PW). Intensive sonication was used to make well dispersed and homogeneous composites.
Abstract: Phase change nanocomposites were prepared by dispersing γ-Al2O3 nanoparticles into melting paraffin wax (PW). Intensive sonication was used to make well dispersed and homogeneous composites. Differential scanning calorimetric (DSC) and transient short-hot-wire (SHW) method were employed to measure the thermal properties of the composites. The composites decreased the latent heat thermal energy storage capacity, L
s, and melting point, T
m, compared with those of the PW. Interestingly, the composites with low mass fraction of the nanoparticles, have higher latent heat capacity than the calculated latent heat capacity value. The thermal conductivity of the nanocomposites was enhanced and increased with the mass fraction of Al2O3 in both liquid state and solid state.
42 citations
01 Jan 2010
TL;DR: In this paper, the thermal conductivity of stable nanofluids containing graphene oxide nanosheets was measured by a short hot wire technique, and the result showed that the thermalconductivity of GO-EG nanophase was almost constant within 7 days.
Abstract: 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.© 2010 ASME
12 citations