Experimental investigation of nano-particle deposited wick Structure's heat transfer characteristics

Abstract

Recently, nanotechnology attracts more and more attention in heat transfer system. Many studies have shown that using nanofluid as the working fluid can improve the thermal performance of the heat pipe. In this paper, the preliminary effort of applying nano-surface engineering on the heat pipe wick to fabricate the nano-structured wick structure has been carried out. Experimental investigation has been performed to determine the effect of the heat source power, mesh aperture and the wick surface structure on the total thermal resistance of the wick structure. When the heat source power increased from 20 W to 30 W, then to 50 W, the evaporation resistance decreases 25.9% and 13.7% respectively, while the conduction resistance increases 24.8% at first and then decreases 9.5%. The evaporation resistance is less with than without the wick structure, and it increases with the increase of mesh aperture. When the mesh aperture increases from 75 μm to 150 μm, then to 460 μm, the evaporation resistance increases 1.9% and 1.7% respectively. Whereas, the wick structure, as well as the mesh aperture have slight influence on the conduction resistance. The experimental results suggest that the nano structure on the surface can efficiently decrease the evaporation resistance but increase the conduction resistance at the same time. Compared to the wick structure with smooth surface, the evaporation resistance of nano-surface deposited by 0.01% TiO2 and 0.02% TiO2 has decreased 4.3% and 15.5%, respectively. This study provides a reference for the preparation of the heat pipe with greater performance in the future.