2022 年 88 巻 906 号 p. 21-00328
In the present study, we have attempted to investigate a feasibility of exhibiting a significant trapping performance by means of multi-pairs of magnetic poles. We here focus on the two representative types of configurations using two pairs of magnetic poles. That is, the first is a vertical configuration of two pairs of magnetic poles, where each pair of magnetic poles is arranged perpendicular to the flow direction, and the second is a parallel configuration, where each pair of magnetic poles is arranged along the wall surface of a circular cylinder. As in the previous study for one pair of magnetic poles, we have here investigated the behavior of magnetic rod-like particles in a Hagen-Poiseuille flow, by means of Brownian dynamics, in the above-mentioned two pairs of magnetic poles, which induce magnetic forces to function to trap magnetic particles around the magnetic poles. In the case of the vertical arrangement of the two pairs of magnetic poles, a largely-packed aggregate is trapped between the first pair of magnetic poles, and this trapping characteristic is reproduced between the second pair of magnetic poles. In this case, these large clusters are mainly formed in the center area of the cylinder perpendicular to the flow direction. In contrast, for the case of the parallel arrangement, a largely-packed cluster is formed between a pair of magnetic poles and located along the wall surface. Different from the previous arrangement of magnetic poles, this largely-packed cluster may sufficiently survive and be trapped between the poles by shifting the position nearer to the wall surface. From these results, we suggest that the parallel arrangement of magnetic poles gives rise to a better trapping performance.
