Experimental Study of Al₂O₃ Nanofluids on the Thermal Efficiency of Curved Heat Pipe at Different Tilt Angle

This paper represents an experimental study about the effect of curves related to thermosyphons and heat pipes with different active fluids and inclination angle at the thermal efficiency. The nanofluid utilized in this work is an aqueous soluble of Al2O3 nanoparticles with 35 nm diameter in pure water. The test saturation level of nanoparticles is 0%, 1%, and 3%wt. All the experiments were conducted and repeated at inclination angle of 30°, 60°, and 90° (vertical). The article presents the gravity impacts on the heat transfer characteristics in different angles and the effects of working fluids and tilt angle of heat pipe tube by the addition of nanoparticles and weight fractions on the thermal efficiency of heat pipe at different inclination. According to the experimental results, the heat pipe at the tilt angle of 60° generates the superior results. At a particle volume concentration of 1%, the use of Al2O3/water nanofluid gives significantly higher heat transfer.