Performance analysis of cylindrical heat pipe using nanofluids - An experimental study

The present work analyzes the thermal performance of a cylindrical copper mesh wick heat pipe using water based CuO nanofluids. The studies are extended further by varying the heat pipe inclination angle and heat input. Thermophysical properties of CuO/DI water nanofluids are also effectively analyzed. The reduction in thermal resistance ratio is about 23.83% and 10.43% respectively for 1.0 and 1.5 wt.% of CuO nanofluid compared with low concentration. Evaporation and condensation heat transfer coefficient ratios are improved by the use of CuO nanofluid and the maximum enhancement obtained is 30.50% and 23.54% respectively for an optimum tilt angle of 60°. Thermal efficiency of heat pipe tends to increase with the heat load and inclination angle and an improvement of 33.34% is observed for 120 W heat load at 60° inclination angle compared with the horizontal heat pipe. After the experimentation, characterizations of mesh wick structures are carried out. It is found that the deposition of CuO nanoparticles creates a thin coating layer on the wick surfaces in evaporator section. This increases the surface wettability and enhances the thermal performance of heat pipe.