Affiliations: [a] Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi, Japan | [b] Department of Mechanical Engineering, Doshisha University, Kyotanabe, Kyoto, Japan
Correspondence:
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Corresponding author: Yuhiro Iwamoto, Ph.D., Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Room 904, Building #3, Gokiso-cho, Showa-ku, Nagoya, Aichi, 466-8555, Japan. Tel.: +81 52 735 7542; Fax: +81 52 735 5442; E-mail: iwamoto.yuhiro@nitech.ac.jp
Abstract: Mn-Zn ferrite-based magnetic fluid is temperature-sensitive. Because of the low Curie temperature of Mn-Zn ferrite particles, magnetization is dramatically attenuated as the temperature rises. This temperature-dependent magnetization can be used to transport heat by magnetically driving a fluid via the application of a non-uniform magnetic field and heat. A potential application of this scheme is long-distance heat transport without the use of mechanical pumps. In the present work, a miniaturized magnetically-driven heat transport device with an inner diameter of 𝜙1.54 mm and a flow path length of 1,500 to 6,000 mm was fabricated. The influence of flow path length on the flow rate induced by the magnetic body force was investigated experimentally and theoretically. Although the flow rate decreased with increasing flow path length due to friction loss, the driving pressure increased with rising heater temperature because of the temperature-dependent magnetization. The influence of flow path length on the driving pressure is relatively insignificant. An increase in the flow path length leads to effects that both attenuate and enhance the driving pressure. Substantial long-distance (6,000 mm) heat transport was realized by applying a non-uniform magnetic field and heat.
Keywords: Magnetic nanofluid, heat transfer, magnetic fluid, temperature-dependent magnetization, energy conversion
