In this study, a novel rotating permanent magnetic actuator (PMA) system is proposed to manipulate magnetic nanofluids to pump of chemicals inside micro-sized channels with a circular path. The PMA consists of two permanent magnet pairs and a rotor-like structure. A semicircular-shaped microchannel with a square cross-section area is located at the top of the actuator in order to investigate the performance of the PMA. Fe3O4-water magnetic nanofluid is employed as a working fluid for the manipulation inside the microchannel. In the first stage of this work, a numerical survey is conducted to determine the most suitable angular distance between permanent magnets of a pair in terms of generated magnetic field form in the microchannel region and velocity distribution of magnetic nanofluid within the semicircular microchannel when the permanent magnets are stationary. Preliminary experiments are then carried out for the stationary permanent magnets to validate the predicted flow-field results. Performance tests for different PMA speeds (7.5-30 rpm) and particle concentrations (1-3% by vol.) indicate that it is possible to manipulate the magnetic nanofluid inside the semicircular channel within a velocity range of 58.7-940 µm/s, which corresponds to a flow rate range of 0.56-9.02 µL/min. The results confirm that the proposed PMA system provides flow rate requirements in analytical microfluidic applications such as low flow drug delivery (1-10 µL/min), cell sorting (6.1 µL/min), and pathogen detection (3-5.83 µL/min).

中文翻译：

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一种用于具有磁性纳米流体的微型泵浦装置的旋转永磁执行器

在这项研究中，提出了一种新颖的旋转永磁致动器 (PMA) 系统来操纵磁性纳米流体，以将化学物质泵入具有圆形路径的微型通道内。PMA 由两个永磁体对和一个类似转子的结构组成。一个具有方形横截面面积的半圆形微通道位于执行器的顶部，以研究 PMA 的性能。Fe3O4-水磁纳米流体被用作微通道内操作的工作流体。在这项工作的第一阶段，进行数值调查以确定一对永磁体之间的最合适的角距离，即当永磁体静止时，微通道区域中产生的磁场形式和半圆形微通道内磁性纳米流体的速度分布。然后对固定永磁体进行初步实验，以验证预测的流场结果。不同 PMA 速度 (7.5-30 rpm) 和粒子浓度 (1-3% vol.) 的性能测试表明，可以在 58.7-940 µm/s 的速度范围内操纵半圆形通道内的磁性纳米流体，这对应于 0.56-9.02 µL/min 的流速范围。