Properties of Stable Aqueous Nanofluids Composed of Copper Nanoaggregates for Enhancing Heat Transfer

In this work, a poly(vinyl pyrrolidone) (PVP)/poly(ethylene glycol) (PEG)/copper (Cu) nanocomposite was successfully synthesized using a one-pot method and dispersed in water to prepare aqueous nanofluids. The enhancement of the convective heat transfer coefficient was 20.86%, and the viscosity (0.949 mPa.s) was similar to that of pure water. The PVP and PEG shell effectively improved the thermal cycle stability by isolating the Cu cores from the environment. Particle size, morphology, elemental distribution, thermal stability, valence state, dispersion stability, viscosity, convective heat transfer coefficient, and thermal cycle stability were investigated using a scanning electron microscopy (SEM), zeta-potential analysis, energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), an Ubbelohde viscometer, and an ultraviolet spectrophotometer. The convective heat transfer coefficient of the nanofluids was numerically calculated, and then, the interaction and dispersion mechanism of PVP/PEG/Cu was also discussed.

Automated summary

A PVP/PEG/Cu nanocomposite was successfully synthesized using a one-pot method and dispersed in water to prepare aqueous nanofluids. The nanofluids showed improved convective heat transfer coefficient and similar viscosity to pure water. The PVP and PEG shell enhanced the thermal cycle stability by isolating the Cu cores from the environment. The properties and dispersion mechanism of the nanofluids were investigated using various characterization techniques.