Basic Study on the Relationship between Heat Transfer and Fluid Flow of Magnetic Functional Fluid

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Relationship between heat transfer and fluid flow of a magnetic fluid under magnetic field was investigated experimentally. Experiments were performed in both laminar flow and turbulent flow. Uniform or non-uniform magnetic field were applied to magnetic fluid flow with changing magnetic field intensity, magnetic field direction and so on. Moreover, in order to better understand heat transfer phenomena of this research, the velocity distribution of the magnetic fluid flow was measured by the Ultrasonic Velocity Profile (UVP) method. The results show that in the case of laminar flow, heat transfer was locally enhanced by applying magnetic field in the region where the magnetic field exists. This enhancement of heat transfer under the uniform magnetic field is larger than that under the non-uniform magnetic field. According to the results of the velocity distribution measurements, it seems that these heat transfer enhancements were caused by different mechanism between applying uniform magnetic field and applying non-uniform magnetic field. In addition, since flow resistance increases by applying magnetic field, the relationship between heat transfer enhancement and increment of flow resistance was evaluated.