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Purpose - This study aims to reveal the temperature rise characteristic of magnetorheological (MR) fluid in a multi-disc MR clutch under slip condition, including the temperature distribution regularity and the impact factors. Design/methodology/approach - Three-dimensional transient heat conduction equation for the MR fluid in the working gap was derived based on the heat transfer theory. Then, numerical simulation was conducted to analyze the temperature field of MR fluid. Furthermore, an experimental study was performed to explore the temperature distribution of the MR fluid in radial and circumferential directions, as well as the effects of disc groove, slip power and gap size on temperature rise characteristic of the MR fluid. Findings - The results show that temperature appears to be largest in the center of the working gap and the temperature difference increases with the slip time. However, the temperature field in a circumferential direction is basically the same, but it presents slightly lower in the groove area. The temperature of the MR fluid increases linearly with the slip time and the rise rate increases with the slip power. Moreover, the temperature rise value decreases with the increase of gap size. Originality/value - In this paper, the temperature gradients, both in radial and circumferential directions, are experimentally measured going beyond the estimation by computer simulations. In addition, the factors that influence the temperature rise characteristic of MR fluid were fully analyzed. The results could provide a reliable basis for the development of cooling technology for high-power MR devices. [ABSTRACT FROM AUTHOR]

Material properties of the components of magnetorheological (MR) fluids are critical to their control accuracy and service life. The aim of this study was to reveal the effects of temperature on the material properties of MR fluid components. In this paper, a detailed introduction to the components of MR fluids, including main performance indicators and commonly used materials, was presented at first. Then, theoretical analysis and experimental investigation were performed on the temperature-dependent material properties of MR fluid components. These material properties included the magnetization properties of the magnetic particle, as well as the shear viscosity and thermal expansion of the carrier fluid. Experimental results indicated that both the mass magnetization and coercivity of MR particles decreased as the temperature increased and the phenomenon was particularly obvious at high temperatures. Moreover, an increasing temperature could lead to a severe decrease of the shear viscosity and a relatively large thermal expansion of the carrier fluid. Research results from this study may serve to provide a theoretical and an experimental basis for the preparation of MR fluids with high thermal stability. [ABSTRACT FROM AUTHOR]