Effect of temperature and concentration on thermal conductivity and viscosity of ferrofluid loaded with carbon nanotubes

The aim of this paper is to investigate the thermal conductivity and viscosity of a hybrid nanofluid containing tetramethylammonium hydroxide (TMAH) coated Fe 3 O 4 nanoparticles and gum arabic (GA) coated carbon nanotubes (CNTs), experimentally. The magnetic nanoparticles and CNTs are physically attached as the result of interaction between the TMAH and GA molecules. The morphology and structure of the samples are characterized with X-ray diffraction (XRD) and transmission electron microscopy (TEM). The experiments are carried out in the magnetic nanoparticles volume concentration range of 0.1–0.9 %, CNT volume concentration range of 0.05–1.35 % and the temperature range of 25–55 °C. The viscosity of the hybrid nanofluid increases with the increase of volume concentration, while it decreases with the increase of temperature. Besides, results show that hybrid nanofluid behaves as a shear thinning fluid. Furthermore, it is observed that the thermal conductivity of the hybrid nanofluid enhances with temperature and volume concentration.