Investigating rheological properties of low-content Fe₃O₄ magnetic fluid using capillary rheometer

Abstract

A capillary rheometer operating at prescribed temperature and pressure was set up. The measurement principles of the capillary rheometer were introduced. The equipment constant was obtained using standard liquids (e.g. water with known viscosity), and the rheometer was thus calibrated. The different carrier liquids viscosities of Fe₃O₄ magnetic fluid (MF) were measured at different flow rates. The experimental data were compared with the results of a theoretical equation derived in this study. Finally, the effect of temperature was investigated. Due to the effect of different carrier liquids, xylene-based and silicon oil-based MF show Newton behavior, but the hydroxyethyl-cellulose (HXC)-based MF shows non-Newton behavior of shear thinning. The difference between the experimentally measured viscosity and the theoretical prediction is lower for dilute MF, whereas, the difference is large for highly concentrated MF. The viscosity decreases quickly with the increase of temperature.

Keywords

viscosity / rheometer / magnetic fluid