Experiments on thermal performance of heat pipes using nanoparticle layer as the wick

To enhance the usability of heat pipes and vapor chambers as the cooling device for portable electronic systems, necessity of thin wick is rapidly increasing. In the present work, the layer of silica nanoparticles of about 10 mu m in thickness was formed on the copper tube inner wall to explore experimentally if it works as the thin wick. It was demonstrated that in comparison with the ordinary heat pipe using a wire mesh as the wick, the thermal resistance was even improved (0.62 to 0.23 K/W) and the deterioration of the maximum heat transfer rate was not significant (120 to 78 W). This indicated that the present nanoparticle layer can be used as a very thin wick of the heat pipes and vapor chambers. If the mass of nanoparticles deposited on the heat pipe inner wall was sufficient, the thermal performance was not deteriorated even after the maximum heat transfer rate condition was experienced. It was also demonstrated that the maximum heat transfer rate can be enhanced up to 100 W when the nanoparticles were suspended in the working fluid enclosed in the container.