The study of magnetoviscous effect of the ferrofluids considering magnetic dipole interactions

Ferrofluids are excellent candidates for several engineering research fields including dampers, seals, sensors, energy harvesting, and soft robotics. Ferrofluids exhibiting interesting physiochemical properties (magnetization properties, magnetoviscous effect, magneto-optic effect, etc.) under a magnetic field have been at the forefront of research. The magnetoviscous effect is known to be a critical indicator for describing the physical properties of ferrofluids. Nonetheless, the existing model barely meets the urgency for precisely describing the magnetoviscous effect due to the omission of magnetic dipole interactions. This study aims to modify the Shliomis model to improve its accuracy. Firstly, the magnetic properties of ferrofluids necessitate consideration of the magnetic dipolar interaction between the magnetic nanoparticles dominated by Brownian relaxation. Secondly, the modified Shliomis (MS) model is proposed by considering the magnetic dipole interactions. Lastly, the magnetoviscous effect measurement tests are used to verify the accuracy of the MS model, while also exploring the influences of shear rate and temperature on the MS model’s accuracy. The MS model provides a theoretical basis for guiding the engineering applications of ferrofluids.