Abstract
Visualization experiments are conducted on horizontal heat pipes to investigate the effects of Al 2 O 3 or Cu nanoparticles laden in mesh-wick evaporator. The weight of both kinds of nanoparticles is 0.01g, with Cu nanoparticles sintered and Al 2 O 3 nanoparticles sedimented in the evaporator. Three different working fluids are tested and compared under similar conditions. According to the present results, the effect of nanoparticles the maximum heat load Q max is insignificant. Boiling is not observed for water with or without nanoparticles. For methanol and acetone, weak boiling occurs without nanoparticles, leading to improved minimum evaporator resistance R e,min . With these nanoparticles, the boiling seemed either slightly enhanced, unaffected, or even suppressed in different cases. Overall, the sedimented nanoparticles provide insignificant effects to the boiling behavior and the performance of a mesh-wick evaporator.