Research on the preparation of urchin-like CuO-H2O nanofluids and its application in heat pipe

In this paper, the urchin-like cupric oxide-water (CuO-H2O) nanofluids has been prepared using two-step method via ultrasonic concussion which the CuO nanoparticles are uniformly dispersed in deionised water (DI water), and the urchin-like CuO nanoparticles has been obtained via hydrothermal method. The structural properties of CuO nanoparticles are characterised via XRD and SEM analysis, indicating that the nanoparticles have uniform size and good dispersibility. The thermal conductivity and the surface tension of the urchin-like CuO-H2O nanofluids have been studied in detail. The thermal conductivity and surface tension of the urchin-like CuO-H2O nanofluids are both higher than the based fluids, and they increased with the mass fraction increasing. The heat transfer performance of heat pipe using urchin-like CuO nanofluids are experimentally measured on the condition of air cooling. The results show that the start-up time of the heat pipes using nanofluids are greatly lower than that of DI water, and reduce with the mass fraction increasing. The start-up temperature rise of heat pipe becomes larger than that of the heat pipe filled with DI water, and increased with the mass fraction increasing. The utilisation of nanofluids as working medium can enhance the heat transfer performance of the heat pipe.