Thermal properties of heat pipe using titanium dioxide-water nanofluids modified cationic surfactant

摘要

In this paper investigated the effect of cetyltrimethylammoniumbromide (CTAB) surfactant of heat pipe thermal performance using TiO_2-water nanofluid as the working fluid. TiO_2 nanofluids was prepared using titanium dioxide nanoparticles (TiO_2 NPs) and modified with CTAB as cationic surfactant. The particles size of TiO_2 NPs used in these experiment were 21 nm and density of 130 g/L. The base working fluid was demineralized water. The TiO_2-water nanofluid was prepared using a one step method by mixing method under ultrasonication for 10 minutes, TiO_2 NPs concentration of 8% volumetric loading, demineralized water of 100 mL, pH was adjusted at 8, and CTAB of 0.029 w.%. Thermal resistances of the heat pipe containing the TiO_2 - CTAB surfactant (2.8 W°C~(-1)) was lower than those found in TiO_2 NPs (3.12 W°C~(-1)) and pure deminerilized water as the working fluid (5.71 W°C~(-1)). The TiO_2 nanoparticles and cationic surfactant has an important role to reduce the thermal resistance in the heat pipe (2.9 W°C~(-1)). The TiO_2 system and TiO_2-surfactant nanofluid can be decreased the temperature in the wall of heat pipe until 32 and 36%, respectively. The TiO_2 NPs and CTAB cationic surfactant has an important role to reduce the thermal resistance in the heat pipe. This field of research has a great potential for improvement the thermal conductivity of TiO_2 nanofluid that can be applied as heat transfer in the heat pipe. The addition of cationic surfactant into the nanofluid can be used to minimize nanoparticles aggregation and improve the dispersion behavior of nanofluid.