Power Generation Using Magnetic Nanofluids in Millimeter-Sized Channel With In-Phase Mode of Magnetization

Abstract

Magnetic nanofluids (MNFs) are an interesting energy harvesting source. In this paper, the flow energy harvesting was experimentally and numerically investigated in a millimeter-sized channel using an externally applied permanent magnet to control the magnetizing direction of the magnetic nanoparticles (MNPs). Oil-or water-based MNF includes a certain percentage of magnetized nanoparticles and has unique features that vary with the strength of the external electromagnetic field. When the MNF flows through a cross-sectional area of the coil loop, the electromotive force can be obtained by following Faraday's law, because the MNPs act as permanent magnets. When the MNFs are used for flow energy harvesting, the main issue is the in-phase mode alignment of the MNPs magnetization with the coil loop. Without the in-phase mode, the electric power cannot be generated, because the net magnetization of the MNF is zero. Most of the previous research works, however, have not considered it. Thus, to implement this mode, we proposed an externally applied magnetic field generated by a cylindrically shaped permanent magnet. Short and closed Teflon tubing with a 1.5 mm inner diameter, containing the MNF, was located inside long silicon tubing and moved along the positive and negative directions by a pump. Then, the generated voltages were measured, and exhibited similar results to those obtained analytically. In the same way, we calculated and experimentally tested a chain type of Teflon tubing.