Design and research of ferromagnetic fluid micropump with double rotating magnetic sources.

• Dual-rotating magnetic source positive-displacement ferromagnetic fluid micropump. • Coupling magnetic force of the ferromagnetic fluid plug enhanced. • Influence of magnetic pole direction on magnetic field in microchannel examined. • Various factors such as maximum pumping flow rate and pumping height improved. • Pumping failure due to gradual collapse of ferromagnetic fluid clogging. Despite extensive research on ferromagnetic fluid micropumps as novel microactuators, their low pumping flows and driving forces limit their development. There is an urgent need to improve the performance of ferrofluid pumps from the perspective of structural improvement. Based on the driving and sealing principles of ferrofluids, this study proposed a dual-rotating magnetic source positive-displacement ferromagnetic fluid micropump. The results show that the coupling magnetic force of the ferromagnetic fluid plug was enhanced by the dual rotating magnetic sources. Furthermore, the influence of the magnetic pole direction on the magnetic field in the microchannel and the optimal center declination angle of the double-rotating magnetic source were determined. The maximum pumping flow rate, pumping height, maximum tolerated speed, and pumping stability of the double-rotating magnetic source ferromagnetic fluid micropump were significantly improved. Moreover, the key to the pumping failure of the micropump was the process of foam formation at the tail of the ferromagnetic fluid plug in the microchannel until the entire plug gradually collapsed. Furthermore, the speed of the ferromagnetic fluid plug and strength of the magnetic field were the most critical factors affecting the process. [ABSTRACT FROM AUTHOR]