Research on viscosity of magnetic liquids in magnetic field

With the development of research about sensors based on magnetic fluid, the effect which was produced by the viscosity of magnetic liquid on dynamic characteristics of sensor was paid more attention. The changing of viscosity with the external factors become the hot spot. This paper studied magnetoviscous characteristic of magnetic liquid and other affecting factors to influence its viscosity. And the device was designed based on principle of Helmholtz coils, which could produce adjustable uniform magnetic field. The coils are placed outside the rotational viscometer, measured viscosity change of magnetic fluid under a certain magnetic field. And using the vertebral plate viscometer, the viscosity changes with temperature and shearing rate was studied. The results show that the viscosity of magnetic fluid will increases with an increase of magnetic field, and be affected by the angle between the direction of magnetic field and scroll vector of magnetic fluid. The viscosity decreases with the increasing of temperature. The liquid was non-newtonian flow, the apparent viscosity of which reduces with increasing of shearing rate. These results are beneficial to the dynamic characteristics research on sensors.