Investigation on viscosity of Fe3O4 nanofluid under magnetic field

Thermal conductivity enhancement of base fluid by magnetic nano-particle under the magnetic field is a hot topic in science, but fewer studies focus on the viscosity properties which affect the thermal performance of base fluid. This article presents an experimental investigation on the viscosity of water based Fe3O4 nanofluid under different magnetic fields. Adjustable magnetic induction was got by improving the test region of SV-10 viscometer. By this improved viscometer the viscosity of Fe3O4 nanofluid in the magnetic field was tested. The ranges of magnetic induction, volume fraction and temperature are 0–30 mT, 0.5%–5% and 293–333 K. The results show that the viscosity of Fe3O4 nanofluid increases with the increase of magnetic induction and solid volume concentration, and decreases with the increase of temperature. Based on the experimental results, an empirical correlation was developed to predict the viscosity of Fe3O4 nanofluid at various temperatures, volume concentrations and magnetic inductions. The correlation presents an excellent agreement with experimental results. The proposed equation provides a useful engineering tool for analysis and thermal and fluid design applications of ferrofluid.