Abstract
In this paper, an experimental investigaitons were made to analyze the thermal conductivity and viscosity of non-polar magnetic nanofluids with and without influence of magnetic field. Magnetic Fe3O4 nanoparticles were synthesized by chemical coprecipitation method
and stable nanofluids were prepared by dispersing them into vacuum pump oil using sonicator without adding any surfactant. Both thermal conductivity and viscosity experiments were conducted in the volume concentrations from 0.05% to 1.0% and in the temperatures from 20 °C to 60 °C.
Based on the results, without magnetic field, thermal conductivity and viscosity enhancements are 6.20% and 66%, respectively and with magnetic field of 900 G, thermal conductivity enhancement is 69%, with magnetic field of 1300 G, viscosity enhancement is 256% was observed for 1.0% of nanofluid
at a temperature of 20 °C. The viscosity enhancement is more compared to thermal conductivity enhancement at same particle concentration and temperature and magnetic field. The chain-like structure of magnetic nanoparticles aggregates under magnetic field caused the enhancement in both
thermal conductivity and viscosity.