Numerical study on heat transfer characteristics of thermosyphon heat pipes using nanofluids

• Numerical study of nanofluid heat transfer in thermosyphon heat pipes is performed.
• Effect of nanoparticle concentration and operating temperature are studied.
• Fe2O3–water nanofluid with 5.3% volume concentration shows the best performance.
• Results show the improvement the thermal performances of thermosyphon heat pipe with nanofluids.

In this work, a three-dimensional analysis is used to investigate the heat transfer of thermosyphon heat pipe using water and nanofluids as the working fluid. The study focused mainly on the effects of volume concentrations of nanoparticles and the operating temperature on the heat transfer performance of the thermosyphon heat pipe using the nanofluids. The analysis was performed for water and γ-Fe2O3γ-Fe2O3 nanoparticles, three volume concentrations of nanoparticles (0 vol.%, 2 vol.% and 5.3 vol.%) and four operating temperatures (60, 70, 80 and 90 °C). The numerical results show that the volume concentration of nanoparticles had a significant effect in reducing the temperature difference between the evaporator and condenser. Experimental and numerical results show qualitatively that the thermosyphon heat pipe using the nanofluid has better heat transfer characteristics than the thermosyphon heat pipe using water.